AN INVESTIGATION OF THE IMPACT—ABSORBING QUALITIES OF VARIOUS FOOTBALL HELMETS by WAYNE FLOYD CASE AN ABSTRACT Submitted to the College of Education of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF ARTS Department of Health, Physical Education, and Recreaticn 1957 AppI‘O V€d= Alfi W: 4 C// Iknz:;7%:jyfintoye(:7dviser :1 si 2 WAYNE FLOYD CASE ABSTRACT It was the purpose of this study to measure the characteristics of football helmets as regards the deceler- ations of a moving object on impact. This was done by inflicting blows of varying speeds to specific positions on the helmet with a pendulum type mass of .16 slug. Nine different helmets were examined. Their code names were as follows: MH612, MEolO, MH620, RK-TKB, RK—RKA, 83122, S3131, WFBOIO, and WFQOOO. They were mounted on a wooden head which was suspended from the ceiling. Each helmet was tested at the following velocities: six, nine, twelve, fifteen, eighteen,and twenty—one feet per second. Four positions, front, back, right side, and top were used. Five blows were averaged at each velocity for the individual helmets in the four respective positions. An accelerometer measured the deceleration of the .16 slug at impact with the helmets. This was recorded by an oscilloscope which was photographed with a sixteen milli— meter camera, hand cranked in order to take the pictures frame by frame. Conclusions 1. For the helmets investigated, the plastic shell was superior to the leather shell. 2. For the best protection in terms of decelerating a moving object in the front position, helmets should have 3 WAYNE FLOYD CASE ABSTRACT a hard plastic shell with a canvas suspension fitting snugly to the head. 3. If at all possible, helmets should be free from rivets. If rivets are used, they must be adequately covered and have as much distance between them and the head as possible. A. If a canvas suspension is used, it should be constructed in such a way that the suspension firmly fits the head. 5. The review of the literature indicates that con- cussion is most likely to concur on the flatest portion of the skull. The sides of the head, therefore, must be ade— quately protected. This can be accomplished by raising the outbend on the sides to allow more room for the ears and leaving more space between the suspension and the shell. 6. The top needs the most protection due to the relative greater mass of the head and body to be moved when struck in this position, This is best accomplished by a plastic shell with a strong suspension and a distance of at least one-inch between the shell and the suspension. 7. An "all-purpose" helmet needs a hard plastic shell with a strong canvas suspension in which the head is firmly fitted, not only on top but around the sides above the ears. AN INVESTIGATION OF THE IMPACT—ABSORBING QUALITIES OF VARIOUS FOOTBALL HELMETS by WAYNE FLOYD CASE A THESIS Submitted to the College of Education of Michigan State University of Agriculture and Applied ‘ Science in partial fulfillment of the requirements for the degree of MASTER OF ARTS Department of Health, Physical Education, and Recreation 1957 ACKNOWLEDGMENT The writer wishes to express his sincere thanks to Dr. Henry J. Montoye who assisted in the general lay out of the experiment and whose constructive criticism was of the utmost value. Acknowledgment also goes to Dr. Wayne VanHuss who assisted in performing the experiment, to Kurt E. Utley who was in charge of all the electrical work, and Everett N. Huby, the photographer, who took all the pictures. W.F.C. TABLE OF CONTENTS CHAPTER I. THE PRWBLEM. Statement of the problem Importance of the study. Limitations of the problem. II. REVIEW OF THE LITERATURE Medical literature Aviation literature Literature in the field of athletics and physical education III. METHODS OF PROCEDURE. The equipment used Experimental design IV. RESULTS V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS. Summary Conclusions. Recommendations BIBLIOGRAPHY . . . APPENDIX A--Recordings on Oscilloscope 27 27 36 41 58 58 59 60 61 64 TABLE I. LIST OF TABLES Direct Fatalities: Injuries. Specific Locations of LIST OF FIGURES FIGURE PAGE 1. Percentage Comparisons——Football, Head and Spinal Injuries Direct Fatalities, l9A7-l956 . 5 Percentage Comparisons——Football, Adominal and Internal Injuries, Direct Fatalities, 19A7- CL} 1956. 6 3. Relationship Between Pressure-Time and Degree of Cerebral Concussion. . . . . . . . . 12 A. Pendulum Type Apparatus to Provide Dynamic Load Test. . . . . . . . . . . . . . . l9 5. Helmet on Wooden Head with Pendulum in Position . 28 6. Close-Up of Oscilloscope. . . . . . . ’. . 28 7. Pendulum In Starting Position . . . . . . . 31 8. Pendulum in Motion. . . . . . . . . . . 31 9. Camera, Release Switch, Oscilloscope, and Recorder in Position . . . . . . . . . 35 10. Helmet Outline Showing Impact Points. . . . . 37 ll. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet ME6lO (Second Run) . . A5 12. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet WF20lO . . . . . . A6 13. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet RK—TK5 (M.S.U. Helmet). A7 1A. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet MH612 . . . . . . A8 15. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet RK-RK—A. . . . . . A9 16. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet S3131 . . . . . . 5O TABLE 17. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet MH620. 18. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet S3122. l9. Deceleration of .16 Slug at Various Velocities Upon Impact with Helmet WF2000 (Second Run) 20. Comparisons of Helmets in Deceleration of .16 Slug Moving at Various Velocities for Front Position. . 21. Comparisons of Helmets in Deceleration of .16 Slug Moving at Various Velocities for Back Position. 2:. Comparisons of Helmets in Deceleration of .16 Slug Moving at Various Velocities for Right Side Position 23. Comparisons of Helmets in Deceleration of .16 Slug Moving at Various Velocities for Top Position. V 1 PAGE 51 \fi \JJ 55 57 CHAPTER I THE PROBLEM There are various types of football helmets in exis— tance today. The most popular have leather shells with a canvas suspension covered by foam rubber and a thin foam rubber padding around the inside of the shell; in others the canvas suspension is not covered, Some have plastic shells with a strong canvas suspension which fits snugly on the head; in others the suspensions vary in regard to covering, e.g. foam rubber, absorblo, and many other new impactabsorbing materials. It is surprising how little actual research has been done to determine the comparative protective qualities of these many helmets being manufac— tured today. Statement of the Problem It was the purpose of this study to measure the characteristics of football helmets as regards the deceler- ations of a moving object on impact. This was done by inflicting blows of varying speeds to specific positions on the helmet. Importance of the Study There are various factors that should be considered in building a well-constructed protective football helmet. 2 It was but one of these factors, that of deceleration, which was investigated in this study. The importance of a low deceleration may be demonstrated with a hypothetical example. A man wearing a wool glove hits a brick wall With his hand. The possibility of him injuring his hand is much greater than it is for another man who hits the same wall with the same force wearing a heavily padded boxing glove. In this example the hand in the wool glove had a high deceleration and the hand in the boxing glove a low deceleration. During the past twenty-three years, half of the A09 direct gridiron fatalities have resulted from head injuries. Furthermore, the Cornell tests show that the helmets of today are inadequate to withstand a concussion-causing blow.l Research which might in any way help to reduce the number of gridiron fatalities resulting from head injuries must be considered of great importance. In the 2Ath Annual Survey of Football Fatalities (1931-1955), it was brought out that fatalities directly due to football have averaged seventeen and one-half per year.2 1William H. White, "Armor That Does As Much Harm As Sports Illustrated, October 31, 1955, pp. A6-A7. Good,"I fiCommittee on Injuries and Fatalities, American Foot— ball Coaches Association, Dr. Floyd R. Eastwood, Chairman, Twenty-Fourth Annual Survey of Football Fatalities, January, 1956, p. 2. 3——__7 .___r-— —.3——' ' 7— v- 3 A further tabulation since 19A7 of the specific location of fatal injuries showed that: ”The head and face area accounted for 59.56 per cent of all fatalities, the spine for 20.59 per cent, and abdominal-internal for 19.85 per cent."3 An analysis of the data by specific location of the blow revealed that both spine and head and face injuries were procured by blows to the top of the head. Combining these two results showed that 80.15 per cent of all injuries were due to traumatic blows to the head.)4 a. Blows to the front and side of the head incurred 23.5A per cent of all injuries. b. Blows to the top of the head (resulting in spinal injuries) incurred 20.59 per cent of all injuries. c. Internal injuries ranked third with 19.85 per cent of all injuries. d. 13.95 per cent of all injuries were acquired by traumatic blows to the back of the head. This means that the most hazardous areas of the body are ranked: (1) both sides and front of the head, (2) top of the head, (3) internal organs, and (A) back of the head. It is obvious to see that the head area requires the best possible protection. It might also be noted that more changes have taken place in the manufacture of headgear than in any other piece of equipment. Still the percentage 31bid., p. 3. “Ibig., p. 3. of total fatal head and spinal injuries has risen steadily since 1931 and four per cent since 19A7. [See Figure 1.] In internal-abdominal injuries, where far less attention has been given in design of protective pads for hips and back, there has been a steady decrease.5 [See Figure 2.] Lombard, _t g1, indicate in their research the need for more precise thinking, in engineering terms, of the mechanical factors involved in the field of head injury, the correlation of the mechanical factors with the biologi- cal factors and findings, and further investigation of the general subject. Limitations of the Problem It must be realized that a low deceleration rate does not necessarily mean there will be fewer head injuries. There are many other circumstances to be considered such as duration of impact, type of impact, and position of im- pact. Some types of helmets may lose part of their durabi- lity with each blow or series of blows. The temperature 5Committee on Injuries and Fatalities, American Foot- ball Coaches Association, Dr. Floyd R. Eastwood, Chairman, Twenty-Fifth Annual Survey of Football Fatalities, January 7, 1957, pp. 21-22. 6Charles F. Lombard, Ames Smith, Herman P. Roth, and Sheldon Rosenfeld, "Voluntary Tolerance of the Human to Im— pact Accelerations of the Head," The Journal of Aviation Medicine, 22:2:109. W]. m MADISON“ w and Splul Injuriu Direct Paulina PROM 1947 - 1956 7311— , — I - L. H 1 ‘ F F ! f 3 721, r Lf / --:l - i . ' 1 , 1 ' i F a , ; i .I r/” ' ; ' l / 1 711 T I i 5 ,/ v /’ 702.. /j 331' e w - - -- rung-1937 1943 1949 1950 1951 1952 1953 1953 1955 1953 53.031 33.927. 39.331 70.197. 7145271.”; 71.53: 72.12: 72.ozz7z.osz MntIVC Ava-ago. - Band on :11 33331131.. reported you-1y .1.an 1931. m; - W8 momma Abdominal and lntarnal Injurlaa Intact Patalltlaa 1947 - 1956 PM! 1...“-.. -4 291 271 i\ i I 261 .7 I x‘ . \ tut-1947 19138 1949 1950 1951 1952 1953 19510 1955 1956 28.661 28.00% 27.621. 27.022 26.151253” 25.901 25A” 25.“! 25.177. Mann Auras“ - Baud on all fatalitiaa raportad yaarly aloea 1931. 7 may be an important factor: some types of plastic may be- come harder in cold weather and softer in warm weather. Results based on this study were made on nine different helmets. It would have been far better to investigate more than one helmet of a given type but lack of funds prohibited this. The impacts were limited to one location at each position. A cluster of impacts around each position would give a more valid representation of the blows received in football. It was assumed that the most expensive helmets were of better quality. It would have strengthened the study to investigate all football helmets manufactured by various companies. No direct conclusions as to the best type of plastic or leather shell, suspension, or foam rubber padding could be drawn until all known types are examined. This could be achieved only with financial help from some large manu— facturer. Only the right side of the helmets were tested, thus the assumption was drawn that both sides were identical. It would have improved the study to test both sides. CHAPTER II REVIEW OF THE LITERATURE The soure of literature in relation to this problem was divided into three categories or fields of work., The first, in the medical field experimenting with concussive effects on the skull; the second, in the field of aviation on new type head gear; and the third, in the field of athletics and physical education. Medical Literature Gurdjian, et a1,1 thought it more accurate to measure the acceleration of the skull rather than the object striking the blow as in most previous studies. The accelero— meter was attached to the skull on the opposite side to where the blow was struck, due to the fact that the skull deforms markedly under impact. Ball peen hammers of various weights were used on dogs of different weights. The head was free to move at impact, being supported by the left hand while the right hand was used for the hammer. An attempt was made to produce a concussive effect with the first blow, but in some cases two, three, or even more blows 1E. s. Gudjian, H. R. Lissner, F. R. Latimer, B. F. Haddad, J. E. Webster, "Quantitative Determination of Accel- eration and Intercranial Pressure in Experimental Head Injury," Neurology, 3:6:A17, June, 1953. were required to obtain this effect. In each case minimal or moderate concussive effects were obtained with acceler- ations ranging from 250 to over 500 Gs. There were disadvantages of mounting the accelero— meter on the skull. The skull was sometimes subject to a slight twisting or turning at impact and the linear accelero- meter was thus unable to measure the true value in Gs. As a result of this preliminary study with twenty- four experiments, no pattern of relationship between sever— ity of concussion and magnitude of acceleration could be determined. A study of the intracranial pressure change at the time of impact suggests that the time duration of the pressure increase is more significant than the maximum levels obtained. It was also brought out that: The increase in intracranial pressure at the time of the impact, in a head that is permitted to move, is produced by two separate causes: the first being due to deformation of the skull and the second being due to acceleration or the sudden setting of the head to motion. It must be remembered though that the skull on the opposite side of the blow may have a pressure which decreases to zero or below. Gurdjian and Webster3 bring out the fact that in a direct blow, the head alone is most subject to injury but 2E. S. Gurdjian and J. E. Webster, "Recent Advances in the Knowledge of the Mechanism, Diagnosis, and Treatment of Head Injury," American Journal of the Medical Sciences, 226:215, August, 1953- 3Ibid., p. A22. 10 in an indirect blow, other parts of the body are also sub— ject to injury. DeHavenu suggests that the majority of severe in- juries occur because the victim is thrown about following the initial impact and not just because of the initial im— pact. Certain measures providing a slow deceleration of the body will make it possible for the human to withstand a large number of Gs without fatality. More research directed at counteracting the effects of impact is needed to help put a stop to the many head injuries imposed by football. Gurdjian, gt al,5 showed in a later study that accel— eration, deceleration, and compression may cause the fol- lowing physical defects on the head and its contents: (1) Deformation of the skull, producing compression of the contents due to decrease in volume. (2) A sudden increase in intracranial pressure at the time of impact. (3) Mass movements of the intracranial contents. (A) Distortion of the skull and dural septa. 8(5) Shearing off of a portion of the head and contents without necessarily producing an increase in intra- cranial pressure at the time of impact. AH. DeHaven, "Injuries," War Medicine, 2:586,Aug.,195A. " 5E. S. Gurdjian, J. E. Webster, and H. R. Lissner, Observations on the Mechanism of Brain Concussion, Con- tusion, and Laceration," Surgery, Gynecology, and Obstetrics 101:682, December, 1955. ll (6) Shearing and tearing with high levels of increased intracranial pressure such as occur in bullet and shell fragment wounds. Combinations of such ef- fects may occur in certain types of injuries. Damage to neural tissues in head injuries takes place by pushing the tissues together or compression, such as the scalp being compressed or mashed under the point of a blow; by tension or tearing apart of the tissues because of tension produced as the brain rotates with respect to the skull; and by shearing or twisting because of cavitation and pressure gradients. Experiments on seventy—two mongrel dogs verified earlier findings that the longer the duration of the pres— sure exerted upon the brain, the 1ower the pressure required for a severe concussion. The shorter the duration, the higher is the pressure required for a severe concussion.6 Figure 3 shows the relationship between pressure, time, and degree of cerebral concussion.7 Line C shows the slope with most of the severe concussions above the line; line B, the slope with most of the moderate concussions above it; line A, the slope with most of the threshold concussions above. If the head is relatively fixed, a direct blow upon the head results in an increase in intracranial pressure. 6E. S. Gurdjian, H. R. Lissner, J. E. WebSter, F. R. Latimer, and B. F. Haddad, Studies on Experimental Concus— sion, from the Wayne University Neurosurgical Service, March, 195A, p. 678. 7Ibiq., p. 680. 388m 5 BE. . 1.- . -.....r. i . _ fi . . 1.+--+... +1: T- :-a-.T-.- I+L+. . .+....-.-+)...+ 3 c.' n 8 u '31 ’33 1m '93-: 33353333 on 2.25“ n . cacao—8: o + Ea . r , x .V 8 Bowmago 3:0 he an s g an: EA gonad n so: 13 This lasts for a longer period of time than if the head were free to move at impact with a similar blow. Under the later circumstances higher velocities with effective masses are needed in order to cause a concussion. When the head is fixed, the impact tends to act for a longer period of time upon the cranium and its contents. In relation to football helmets, it should be men- tioned that since the head is less likely to move when struck on the top position, more protection is needed in this area. Following impact by a direct blow there is always an area of inbending immediately beneath and around the point of the blow. If the time duration is long enough or the velocity is sufficiently high, the area of inbending may fail, resulting in a depressed fracture. If the inbending at the boundary of the inbended area is not severe enough to cause a fracture, the skull rebounds. The outbending may be so severe that a linear fracture results. Thus the fracture line extends both toward the point of impact and in the opposite direction. Linear skull fractures occur at right angles to the maximum tensile stress produced by outbending of the skull at a distance from the point of impact.8 8E. S. Gurdjian, J. E. Webster, and H. R. Lissner, ”Observations on Prediction of Fracture Site in Head Injury," Radiology, 60:2:226, February, 1953. Generally it might be said that the greater the velocity, the more localized the deformation at the area of impact. The shape of the object must also be considered as responsible for the type of fracture obtained. Tests were conducted on one hundred randomly selected adult skulls. Each skull was divided into twelve parts and a stresscoat applied. The skulls were given a deceleration blow in each area with special care that each area was struck many times. It was shown that if the area of impact is known, a fairly accurate prediction of the location of a linear fracture may be made. By the same way, if the posi- tion of the linear fracture is known, the point of impact may be determined.9 1,10 Lissner, gt substantiated and added to their earlier work by experiments showing that imbending was always indicated directly under the point of impact. In severe blows, cracks radiated out from the point of impact. The cracks were always greatest along the flatest portions of the skull. The sides of the skull are relatively flat. Relating this to football helmets, the supposition could be made that the higher the outbend of the helmet _‘ 9Gurdjian, Webster, and Lissner, "Observations on the Mechanism of Brain Concussion, Contusion, and Laceration," op. cit. 10H. R. Lissner, E. S. Gurdjian, J. E. Webster, "Mechan— ics of Skull Fracture,".Experimental Stress Analysis (Report from Wayne University and Grace Hospital), May, 1950, p. 62. 15 for ear placement, the better the design in relation to skull fractures along the sides of the head. Tests were made on fifty-five completely intact human cadaver heads to find out what effects if any, hair, scalp,- and skull contents had on fractures. It was rather surprising to note that after enough energy had been absorbed to produce a single line fracture, very little more was required for multiple fractures or even complete destruction of the skull. The least energy re— quired for fracture was in the neighborhood of four hundred inch pounds. Above that there were differences due to thickness of scalp, thickness of skull, shape of skull, and a slight change in the position of the blow. In some cases a fracture was not produced even after a force of one thousand inch pounds was administered. Gurdjian, gt gt,ll divided fractures of the skull into three categories where they might occur. The area of primary stress level is the weakest region in the skull and it is here a fracture may start. The area of secondary stress level is the region where a second fracture line may be initiated with additional energy. The area of tertiary stress level is the region where further fracture lines will be caused by more energy, usually resulting in a stellate 11E. S. Gurdjian, J. E. Webster, and H. R. Lissner, '"The Mechanism of Skull Fracture," Radiology, 5A:3:338, March,l950. 16 pattern. It should be remembered that the area of primary stress level varies in different skulls. Aviation Literature ID Lombard, gt gt,l conducted a study on the voluntary tolerance of the human to impact accelerations of the head. Two different weight pendulums were used, one of thirteen pounds and the other 9.AA pounds. Each was used on seven different football helmets. A strain gauge type accelero- meter capable of measuring in excess of five hundred Gs was mounted in the steel head of the pendulum. A thirty-five millometer camera with a film speed of approximately sixteen inches per second was used for recording the characteristics of the pattern. The results of this study showed that the upper limit of linear accelerations which a human can vol- untarily tolerate due to impact blows to the head had not been reached. It was shown that: Always the effect of the locally applied force causing brusing, tension loads on the ligaments or ligamental attachments of the neck muscles, or sharp burning pains in the joints of the cervical vertebre caused the subjects to voluntarily and/or subjectively limit exposure to no higher energy impacts.1 The primary reason for limiting the blows to the top of the head was a generally uncomfortable jolt and local 12Lombard, Ames, Roth, and Rosenfeld, loc. cit. 13Ibid., pp. 111-112. l7 bruising. For the front blow, it was local bruising, neck pains in either vertebrae or ligaments, and sometimes a generally uncomfortable jolt. For the side blows, it was mostly local bruising and an uncomfortable jolt with slight pain in the ligaments. Back blows were limited to local bruising. The Gs tolerated were,for the respective sites: top blows, thirty—four maximum, average twenty—three; front blows, thirty-eight maximum, average twenty-two; side blows, twenty-five maximum, average twenty; back blows, thirty- five maximum, average eighteen.la Motion pictures showed a considerable movement for all sling suspension helmets before the head started to move. A considerable distortion of the face was observed with the bony structure of the head being accelerated away from the softer portions, e.g., the cheeks, nose, eyes. The helmet shells having the most resistance to compression and having a sling suspension were the ones which vibrated upon impact. It is believed from the experience of the authors that psychological factors played the most important part in the limitation of the upper limit of only thirty-eight Gs. Most of the subjects probably have experienced harder blows to their heads in sports and accidents during their youth. This was brought out by Hugh DeHaven who calculated survival Ibid., pp. 111-112. 1A 18 from falls in the order of two hundred Gs. Of course, the body landed in a supine position giving the head an equal deceleration.15 The Air Force upon investigation found it important not only to provide maximum energy absorption but also to limit the acceleration of the head to further help reduce brain injury. It was also found that the greatest disadvan- tage of using a resilient material between the shell and the head for energy absorption was that during deflection it stored rather than dissipated energy. As it deflected,an increasing restoring force was created which reached a maximum at the point of maximum deflection and the energy was returned in the form of a rebound of the helmet from t.16 It was suggested that the space between the the objec helmet and the head be filled by a non-resilient, energy— absorbing material. The apparatus shown in Figure A was developed to provide a dynamic load test. The most successful material tested was cellular cellulose acetate with criss-cross saw cuts into which the foam rubber was molded. The foam rubber was also molded over the surface of the material. It was shown that: By selection of the proper spacing and shape of the cuts, characteristics of the foam rubber used and 15lbid., pp. 115—116. 16"New Helmet Protection Theory Advanced," Aviation Week, 50:A:18, January 2A, 19A9. l9 II} e.g.." 05 would: Illv \ u t \ E: 8... ‘ g .3253 llll. HI I ‘ i u g a a fig.— . . _ .M u . OH was "E laugh #05 03 .3933 . a sh hon-gala: I. :96 11..) dual-m anon. a M 03.80 on . , a: o n.a««.umsé pal-o V» , T5168.” \ a cam 23.... a 90.3.3! . \I\ Ugandunz P\ OH. .3 20 thickness of the rubber in relation to that of the cellular material, a resulting product can be form- ulated having energy-absorbing characteristics which are controllable throughout a fairly wide range.17 Lombard showed that if one considers the effects of a very brief application of a large force to the head, two experimental observations are confronted: a) Accelerations of 100 to 200 Gs cause concussion. b) The absorption of 200 in-lbs. of energy in a short periog of time may cause fatal damage to the brain.1 In these observations, however, one only approximates since, (a) the force acted for approximately 0.25 inch, yet may have caused the acceleration of 0.01 inch while, (b) the absorption of two hundred inch pounds of energy may have occurred in either a fraction or a multiple of a milli- second. In experiments by the Air Force using an aluminum head, the center of gravity was near that of the human head. The accelerometer was mounted near the center of gravity of the brain. It was also shown that since the blow was not delivered on a line with the center of gravity, a cer- tain amount of angular acceleration exists and the accelero— meter will only measure the linear acceleration present. The pendulum mass was of the same order of magnitude as that l7lbid., p. 20. 18Charles F. Lombard, "How Much Force Can Body Withstand," Aviation Week, 50:3:2A, January 17, l9A9. 21 of the head, weighing about twelve pounds and moving on an eight foot radius. This allowed practical energy range up to sixty foot-pounds; An accelerometer was also placed in the center of the pendulum. The pendulum was designed to allow various impact-shapes to be used varying from a flat 19 plate to a one-half diameter hemisphere. The two helmets tested were the U.S.A.F. P-1 and the Protection Incorporation Toptex. Three impact—shapes were used at two impact velocities. Four different positions on each helmet were tested. The acceleration of the head and the deceleration of the impact producing pendulum were measured and recorded.20 In summarizing it was stated: In evaluating this test certain assumptions must be made as to which characteristics are desirable because no explicit criteria for head protection exist. Non-penetration of helmet, minimum movement of head, minimum peak acceleration, maximum energy absorption, minimum tendency to "bottom-out" against heat, uniform protection over entire head and minimum tendency for peak acceleration to become larger with increasing area of contact on helmet, are considered to be desirable. The relative importance of these characteristics is not shown. The Protection, Inc. helmet is better with respect to motion of the head during the blow. The average peak accelerations were lower for the P-l helmet. The energy absorbing qualities were found to be the same. The design characteristic of the Protection, Inc. helmet which minimized the tendency to "bottom- out" particularly with small impact-shapes which would penetrate both helmets, is a deciding advantage. 19O. T. Strand, "Protective Helmet 1m act Testing Equipment," Air Force Technical Report No. 5 20, May, 19A9 p. l. 20Oliver T. Strand, "Impact Effect on Two Types of Protective Helmets," Air Force Technical Report No. 6020, May, 1950, Index iii. 22 On the point of uniform protection over the entire head, the Protection, Inc. helmet was considered better. The tendency for the peak acceleration to become larger with increasing contact area of the impact-shape is a distinct disadvantage of the Protection, Inc. helmet. If contact is made over a large enough area, damaging deceleration to the head might occur without crushing any of the cellular cellulose acetate absorbing material. Poor distri— bution of the blow caused by lack of stiffness in the shell is implied by these data. The distribution obtained by the P-l helmet is, of course,2Eonstant and determined by the suspension pattern. Hendler and Wurzel22 stated that evaluation methods developed in the various laboratories have often been in- genious, but can be improved in two respects. First, the velocity change used in applying blows to the tested helmets should be increased, and second, pressure distributions over the head surface during a blow should be measured. To judge if a helmet is adequate one must have knowl- edge of: (l) the magnitude of the maximum acceleration that the cushioning permits the head to reach; (2) the form of the acceleration-time relation; and (3) the strength, natural frequencies of vibration, and damping of the structural elements of the head.23 21lbid., p. 17. —-——-—— 22Edwin Hendler and Commander Edward Wurzel, "The Design and Evaluation of Aviation Protective Helmets," The Journal of Aviation Medicine, 27:1:6A-65, February, 1956? 2 31bid. It must be remembered that this third factor is undetermined so that any analysis regarding the effects of applied dynamic loads to the head wearing a helmet must necessarily be limited. Literature in the Field of Athletics and Physical Education Hawk,224 commenting on "Brain and Skull Injuries," stated that the one hundred seventy-nine injuries for 3,A8O athletes is not as serious as it appears. The Athletic Ttgiggt classifies any dizziness, partial vision, or head- ache as a "Brain Concussion." Many of these symptoms turn out to be disorders other than brain concussions, as is shown by the fact that the average disability for each in- dividual was only four and three—tenths days. A better helmet, however, will eliminate many of these disorders classified as "other than concussions." It was shown that 16.7 per cent of all football in- juries occurred to the head and neck. This ranks second with the sections of anatomy injured, but is one-tenth of one per cent from being last as for the rate of "days disabled.” This year's survey [Table I] classifies direct fatali- ties as to the specific location of injuries. It is shown 2A‘LG. Kenneth Hawk, Football Injuries Survey for 1952 Season (Houghton, Michigan: Michigan College of Mining and Technology, 1953), p. 3. m4 Aammaaommo ecov .xomc esp mo mflommo> vocab esp mo mpdpadh wcfimsmo mmoc ob 30am 6fime5mpB** 2 sama ca empaapm ceapaaapae* .smma .aaaacam .mpapaaapam Haappoom we am>aam aascca :paamuspcpae qcofipwfioomm/a wagomoo Hapnpoom cmoHLmE< oz“ mo mmapfiampmm paw mmfiLchH co moppHEEoo "meadow oo.ooa ama H OH Hm ma mm mqaeoe ow.m a o o m m o paaaaomam poz ma.ma mm a a ma m s Hacampmm mm. a o o a o o pmaaaoaam poz cps-cpo ma.ma mm o m . 6H s m :pm-:pa amoaaamo mcamm a©.qw mm o a ma m NH umaaaomam 662 mp. a o o o o a **pamm a mmoz am.ma ma 0 H ma 0 m 6ama a6 xaam mo.m 3H 0 a m m m pgmaa-opam aa.m ma 0 0 SA a a papa-ppam mm.a m o o m o H pzmap-pcoam om.m m o o a o m pamH1pcoam me. a o o o o a madame woga wmmm owmpcmopmm kuoe .mp0 mwmaaoo Hoogom opmuHEmm po cm a o 0 ppm Haam.pm swam a 6am He m p m a m *mmmaanmallmmHmbwzH m0 ZOHB :1 -~ ~‘s. .» ~ .-~ lr'va r.'>-(‘-‘ « . a .— o.--- 5. F- ‘ ,1 . ,‘J ‘u‘ -.».4 '”" 391‘». “" Ao«.-L ' - o)!“ >1 V '. “‘ '--.~- g I ‘ P-~ !, w \ . ...-t, -..d 3.: r»; "'11-...” ‘1 ‘-~ .— p“ I ""‘~ v“ ‘r.‘ 2 ‘ .. ._ 1‘ 14..- ‘ -3. f '"""-.-9-_ .4._-‘,‘. H r 1 ~-._ C 1 1 -r “"‘-t_“ 38 with two pieces of tape on the head used as points of meas— urement. Each helmet was tested at three positions: front, badt, and right side. At the end, the head was turned horizontally and each helmet tested at the top position. Three individuals were required to perform this experdxnent. One person checked the helmet to make sure it was stueaight and placed the pendulum in the release box after teach impact. Upon completingtflUjstm3called,'"Ready:" The ptmatographer, operating the camera, upon the signal "Read;”' and when the pip was near center, pulled the rubber cap frwom the open shutter. As the cap left the open shutter, the ttiird person switched the button to release the pendulum. This iiadividual also kept the records of the millivolts per centitneter used at the different impacts and changed the dial <)n_the oscilloscope. Calibration was initially made by noting the differ- ence :ln.levels between the signals when the L.V.D.T. (mOUIIted on pendulum) was rotated from a neutral position “Mlvalale core horizontal) to one in which the sensitive axis (sf the L.V.D.T. was parallel to the force of gravity (fPOrlt part of pendulum perpendicular to ground). In dis— plaCiJig the core, the force of gravity (one G) was repre- Sentexi by the change in single level on the scope, thus allovwing the scope to be calibrated in Gsper centimeter of SCORE? deflection. 39 As a final check, the L.V.D T. was also calibrated in the following manner: 6y———-—--——-—-—w—-——v-——————~——-—.¢—-o --._ \ \ Signal to oscilloscope \ I \ / / \ / _, __ i , x : / (:2 : I —_ E -- M‘- T ---—‘ fl‘f‘f‘rfiw’cfih-(x‘ 47". LVDT The L.V.D.T. and attached mass swung and the maximum deflecrtion of the spring was recorded, as well as the ampli— tude <>f the decelerationpulse on the oscilloscope. The etquations: [F-—force [m--mass in slugs of L.V.D.T. F = ma [ and pendulum bob where [a--deceleration of L.V.D.T. [K--spring constant in pounds F = Kx [ of inch deflection [x--deflection in inches It vmas easily shown again that a = 5%. Since K, x, and m WGPG ‘known, a could be accurately determined from this fornuila. The signal on the scope in centimeters of deflec- 'tior1 represented this deceleration, and another calibration was rnade in terms okasper centimeter of deflection. The initial calibration and this check calibration agreed well Witttin the limits of observational error. A third calibration used mainly to correlate with Lomixard's findings was to check the voluntary tolerance lGVESI. In his experiment he obtained one maximum of thirty- eigyft Gs in the front position. For the two subjects tested in tliis experiment a maximum of thirty-five Gs were recorded. A0 After all the helmets were tested and the film devel- oped, the recordings were measured on a viewert The heights of the pips were recorded, the averages were taken on each helmet at each velocity, and were transferred to G. [See AppendhtA.] The results were shown by graphs. The deceleration r111:e (G) was plotted against velocity in feet per seconds. TTaea experimental design in this experiment is similar to tile? one shown in Figure A which was developed to provide a d;yiaamic load test, and the Air Force experiment by O. T. S t rand, Jr. As stated before in the letter from Protection, In- cc>:rporated, helmets should be tested for:1 1. Protection against repeated low energy impacts. 2. Protection against single high energy impacts. 3. Protection against blows on the sides, back, front, and top of the head. The design of this experiment included all this, I 131.Lis repeated high energy impacts and the so—called "average' b€Plrvmen the low and high energy impacts. 1' 1 Correspondence from Protection, Inc., op. cit. CHAPTER IV RESULTS Upon developing the film, there were no recordings IYDr*either helmet ME610 or helmet WF2000. The shutter on 1:}1e camera had been closed and as a result only blank film cieaveloped. Recordings were taken again and as indicated on 1:}aee graphs the second run was recorded. For helmet MH612 it was impossible to adequately niee:asure the height of the pip in the front and right side tDCD sitions, so these were not included in the graphs. This Flee lmet had been used in the sample run and at the high treeLlocities the intensity had not been turned up. There were nine graphs comparing each helmet with 1.1:53e1f in the four pisitions, [Figures 11 through 19], and iFC>14r graphs [Figures 20 through 23] which compared each IiEalmet with every other helmet in the four positions. As shown in Figure 20, the lowest deceleration re- C3C>Ifided in the front position at twenty-one feet per second ‘NEiES from helmet RK-TKS. It reached a peak of 181.5 Gs at ‘theuity-one feet per second which was 128 Gs below the next 10West recording. It was interesting\to note that the three 1C>Mkest recordings were from the same type helmets, plastic SheElls with canvas suspensions that fit snugly on the head. 7: "$715) 17 ‘3... n . T.r"'.l kafim 99-1—9. A2 The two helmets with the highest deceleration were MH620 and 83131, both exceeding AAO Gs at twenty-one feet per second. In examining the front of helmet S3131 it was discovered that there were two large rivets covered by a three—quarter inch foam rubber strip. The high velocity blows had forced the rivets partially through the foam rubber. Helmet MH620 had an exceedingly weak suspension and ‘tlae? inside mounting, which covered one inch above the holes 17c>rz the ears, was covered by a foam rubber strip about one- C1L151rter of an inch thick. In the tack position, the lowest deceleration at t:vJ€2nty-one feet per second was from helmet ME610 (second ‘FLLI1) from which 156.5 Gs were recorded. The highest re- cc>Ifiding was a leather helmet MH620 from which A86.9Gs were re>crorded; the highest recording from all the helmets in a1.J. positions. However, in its defense,it must be mentioned ttlalfi another leather helmet, MH612, had the second lowest 963(2631eration. The lowest recording for the right side position was 72 - 06 GS recorded from helmet RK—TK5. Two other helmets, SE33.222 and MH610 (second run) also recorded under 100 Gs. TW‘E? highest recording was again from helmet MH620 which IVEEiCi A60.9 Gs. This was 187 Gs above the next highest helrnet. The only protection helmet MH620 provided in this pOEilition was a one-quarter inch foam rubber padding which ‘NELS jpushed against the leather shell by the head. A3 The lowest recording for the top position was 67.9 Gs recorded from the WF2000 (second run). This was the lowest recording from any position at twenty-one feet per second. lhlmets ME610 (second run) and RK-TK5 recorded under 100 Gs. The highest was AO5.2 Gs recorded from helmet WF2010. It was interesting to note the contrast between helmets WF2000 {swecond run) which recorded 67.9 Gs and WF20lO which re- [- W c2c>rvded A05.2 Gs. Helmet WF2000 (second run) has a canvas 8' satisspension covered with a thick foam rubber, of about one- 1131]_i‘inch length. Helmet WF2010 has a foam rubber padding wi1:i_ch fits loosely to the shell. The shells are almost iCicexltical. The lowest average in regard to position, was re- cx3:r’ded on the right side, while the highest average was in true? front position. The review of literature indicated a gr“€?21t deal of protection is needed in the top position be- (NilJJse the head is less likely to move when struck at this pC>ESJ_tion. The results of this study show that the majority Of‘ lielmets give this added protection. The two lowest over-all recordings for the four PC>ESJ.tions were from helmets RK-TK5 and ME610 (second run). TI1E? highest recordings by far, were from helmet MH620. A CC>mparlsoh must be taken to see why helmets RK—TK5 and NugéSlI) had the lowest recordings. The only difference ob- Sel"‘Jed between helmet RK-TK5 and helmet RK-RKA was the SIN3151. The shell in helmet RK—RKA was of softer plastic. H631~mets ME610 and RK-TK5 had very strong shells. AA Helmets RK-TK5 and ME610 both had a very strong canvas suspension, although helmet ME610 had a new type absorblo on the canvas. These suspensions fit around the head above the ears. A look at the graphs shows that at various velocities the curves accelerataialmost straight upward. This seemed to indicate the velocity at which the wooden head made 9 LI? ILA-Oat: I' 1"; (:CDrltact with the shell. 113me Inc 160., 120—— 45 new: 11 mummy or .16 51.09 A1- VARIOUS mums UPON IMPACT um mm H! 610 (snow mm) mm - 2" Front -—- Back - _ Rt. 313. ”W -.-___ Ion --- _, , ,/ °/ // X x/ O ' X . -924." . . .r i — ‘ ”' , ’ o , ~10 z/ I _ _ / a l,,,/"/ 0,1 . (/-{ rift '7/ g: I t” ‘ 1 l I I 2 15 18 21 vnmcm m run run smom 1150 400- 350 m 25‘ N 0 2H 2°HH(§BQ 1i «.- DMLEMIOI I” 450] A6 ms 12 03021331103 or .16 sun A: muons mourns upon mac: mm mm m! 2010 . mm 6, “00—1“ Front—F-__ .. y F‘" E l mk—x_x__. / i i at o . SidW— -- 9*“ - ' X 350.; Top”... .4. / . i ;. 4 x / 1 .~ , E ’ 300 -3— . ’7 1 x O 250 “t‘ / f 4r. [’7' / / ’ / 200 -"' x_/ {I “v /' /" 5 I *L ,/ "I ‘1 . , / / / 150 4.— , , i / [5 j/ J A, // 11/ / ,’ loo—+— p/ I/ Z, / /, .» ' / / / so /,. /. /c’/ o 1 6 ' L 1r + _ mm In rm rm smom A7 Ill 1 0 2 1L 4. I. . . / .a. a . I 21 J l 18 ....1... I 15. 1 I 12 WIHMPIISM LIoD AV .1334 )i‘lTiit +.:ui-+-l-)-+.)+Il||l.lo m 3: 35539 X: 0114,1111! m) E R mmm mam I m monm .. x O .2 m w l _ .. mum . .r. .w 0 o. s . _. MN“ .5 k C D m m o mmm mama. 1 .... T - i l [+111 * 4+ 411+. m m m m m m > w m o . 0' . m “W111“ “617. K! “3‘1 an! M 250 T) l. ‘1‘ L 1369“ x/X/ 200 ‘. ”,- 1, To? A l “- i“ 150 fir a \- 1-2- \ 151 t A ‘1 E \ p 100 7\ \ \ , \\ ,. ,/ Ar 69.! 50 \ x): / - // ’ \ ... / — A / ’t’777731 1.x ‘ 1 ’1 l x l i ] 3 l / -~/’ //Il ,/* +r”f/7*1 l/Hfi/u . z *1 1135’Mlp AA‘A~ ammo- In a noun 15 - momma O? .16 am A! var-1003 vamcnns m mm “1!! mm n—m . mm trout *-+-'——+—- , . Bach ——x——-ae——— ' r Rt. Sid. —'9‘_'0'—" I rap “...—J... / / f, O 1 l 1 , J 1 l 6 T 1%. 1% 13 21 300* . * a ‘ m.” N av IH [Our-Ega- 150—~ 100.. nun-mum I! 6 3° 1 pl 8 .. 1-..- 1 _-_-4___.._.+_-_._+__- - § 8 )- FIGURB 16 - DECELERAIION 0F .16 SLUG AI VARIOUS VELOCITIES UPON IMPACT WITH HELMET S3131 3 Prone 4' Back —-—*——«L—~ Rt. 513. —-e>—-~o- -- 17/ / / // ,6 6, .r' ,/ /,,x.. f/ I .0 I /x/ -1, J’ / . ' ' /." e r ‘/ (I 4’” ..‘r‘ 9- ’7' " / "' ‘l'op ~4- - 4. 4a» artsy-mm " . ' l ' 1 wwwml IN FIGURE 17 DECEMTIOU OF .16 sun A! VARIWS VELOCITIBS UPON IMPACT "11'! M 3620 LHZEND /, .....- ...._.._- // Back ———x----x-w ;/ Rt. Side ——~0———o // 'rop '2' ~ g”? / * f/ / / -' / .' -/‘ x g , / . I "I l / ' / , o O .,/l/ / / O / x 4 / . / / ,. / . / 1”“ . ”I / V’/ l/’ ..- /' / _ -’/ 3.. + — ——+-————--- l -..m. J. 4 _- --—| 6 9 12 15 2 18 21 “room Ill rm Pm SIGOID 51 320* 280- AU IO M l. nu. IN ION-Hagan- 120 DWWTIOR In a FIGURE 18 woman 0? .16 $11!: 400 A! VARIOUS vmocmzs UPON IMPACT . WITH HELMET S3122 “ + 360 -— 6x i 1.1mm I I 320 1‘- Front - - . . Back ———x———K———-- 1. kt. Sldo ——o——-—o——» '. Top -——v-——-¢——-- 280 {~— ; x 240 #7- 200 "" I)" I , ,1 . 160 f- ." i x' A ll / p 120 a» / ! . /A_ I / . m 'T" o O O - / . . +- , A /- // Q " | ,/// /—'/' I 40 ~— ,. / 1...--2’ I //l/. :j.--_’,. 0 «L714».- ..- L i- 4 . 4 0 6 9 - 12 15 18 21 VELOCITY IN 3331' mm SECOND 3607 320+ 280‘ w 2 m W 0 IN END-.38“ 12 ”emu. II c FIG“! 19 DEMO! Ol' .16 sun ' A! VARIOUS WIS urea MAC! m M wnooo (maul) Front 3? Fr Daub ——-x-‘—x—-- Rt. 81.60% Top—*+“ .4».- 1 . 12 15 W Ill ran an small: 53 ..flT'T'f—‘f- m."a--- naturals)":- . ‘ . F 5A ,. I a ... q r! 33.. 5.51.5... . ... .. . .1- %. \ _ 0.x \ . £65865 0 _\ LL38 28: [mafia 858. ESE 8» «358.! 6.824» H4 88: P. §o~.88§8nnu§8u§g§.8§ . 8: on homo 55 . gag-”HERVE an nu 3 N.— o 0 on" a.- nu N.— a o o a 3 3 fl a a o r L p _ _ _ > r P . _ p . L NF L! f p _ p F _ k fl a g _ a _ Y fl . % 4 q q _\ fl 1 a _ _ . «V c 4r LT 2 4 4T H 11 9: .. + H Lr an H + 8~ \ 4| 1| can x. lo... «.5! __ ii 938 Santa \ IT 38.5 I4! «38 ll 53 H L: 4. one \ + .8332 no: 8. manhood.» 88.2» a “ E8 .. a an I 03 3 cu. ho 5383 IH as ho 9 [1 ”LIME r. . < 7.1.1.1..‘zars‘afiw 808% an E 8H Eg a 3 2 2 a o .o a 2 3 2 a . m o a 7%.. .T;1i+1-j\_ Ti; ;_ . +2.5 _. -4 X if IIX . . .4! *\\N\\ .41. K\ 11 \ ll 0\I-w\\ 1 #T ,. \ .M. \ gr. \ Lr \ . t 4. \ I r \ + + L + r! Lr +3.58%»: 11 I 1.1938 39.: IT 285 4 {~33 1.158 \\ .\ BE»...— 25 Eu: 8.. 3E3» «824.» .2 REE: 3.6 3. .8 Egan 5 a5 3 usages”. .. «a BB: 70.: F3” rowu 9 n1 mlma ‘ loan-nan?! HO". “OH WIHHHUOE mgHab .H‘ “Ha—H; 8.: 0!. IO 30:385- IH hurl-HE IO EQHI‘EOU I ”N an»: 57 gflmflugfisg o a 3 2 «a a o \H _ V +3588»: . \ I795 33: I II 38.: I II .38. I96 Inna» \ I3...“ II 885 IT 1| 1T 1 II [F LEG » I Bag E E mg; «Swab 94 Hg 3 on. Bananasgmaaggu Hugo: 9 II nonvma CHAPTER V SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS Summary It was the purpose of this study to measure the characteristics of helmets as regards the decelerations of a moving object on impact. This was done by inflicting blows of varying speeds to specific positions on the helmet with a pendulum type mass of .16 slug. Nine different helmets were examined. Their code names were as follows: MH612, ME610, MH620, RK—TKS, FK—FKM, 83l22, SBlBl, WF20lO, and WF2000. They were mounted on a wooden head which was suspended from the ceiling. Each helmet was tested at the following velocities: six, nine, twelve, fifteen, eighteen, and twenty-one feet per second. Four positions, front, back, right side, and top were used. Five blows were averaged at each velocity for the individual helmets in the four respective positions. An accelerometer measured the deceleration of the .16 slug at impact with the helmets and this was recorded by an oscilloscope which was photographed with a sixteen millimeter camera, hand cranked in order to take the pictures frame by frame. The results were clearly shown with nine IBZZQ'VTIITMD- . - - 4 i‘ 61‘ 59 gmqfim plotting each helmet against itself for the four positions and four graphs plotting each helmet against every other helmet in each position. Conclusions 1. For the helmets investigated, the plastic shell was superior to the leather shell. 2. For the best protection in terms of decelerating a moving object in the front position, helmets should have hard plastic shell with a canvas suspension that fits snugly on the head. 3. If at all possible, helmets should be free from rivets. If rivets are used, they must be adequately covered and have as much distance between them and the head as possible. A. If a canvas suspension is used, it should be constructed in such a way that the suspension firmly fits the head. 5. The review of the literature indicates that con- cussion is most likely to concure on the flatest portion of the skull. The sides of the head, therefore, must be ade- quately protected. This can be accomplished by raising the outbend on the sides to allow more room for the ears and leaving more space between the suspension and the shell. 6. The top position needs the greatest protection due to the relatively greater mass of the head and body to be moved when struck in this position. This is best .4. ”m A WWW” IW- > 5.x. ( 4 : '. 32w ‘m. 60 accomplished by a plastic shell with a strong suspension and a distance of at least one-inch between the shell and the suspension. 7. An "all purpose" helmet needs a hard plastic shell with a strong canvas suspension in which the head is firmly fitted, not only on top but around the sides above the ears. Recommendations The following problems are recommended as a result of this study: 1. Pressure gauges on the four positions inside the head as well as on the pendulum might be used; thus recording the difference in Gs that is transmitted through to the head. 2. The fatigue factor should be studied by con- tinued impacts on the helmets with high velocity blows until they "break down." 3. The various comfort factors such as weight, shape, and stability might be investigated. A. The effect of temperature on the different type plastic helmets should be studied. 5. The weapon angle should be examined, e.g., the effect of the shape and padding on the outside of the helmet in relation to injuries. 6. The time-ratio factor should be studied, e.g., the duration of the blow in relation to the extent of the injury. BIBL IOGRAPHY - .. 34-3.3-3.au-‘17 {‘r ”raw: " ” u. u IIF‘ Iv-‘yfl a“? ... ‘ ‘.J~...-.-.. .I" ‘ Arvin 3.3-1 Jw.u.-» J flung-.V j-‘~I: 1‘ . ' I...~.4 BIBLIOGRAPHY Committee on Injuries and Fatalities, American Football Coaches Association. Dr. Floyd R. Eastwood, Chair- man. Twenty-Fourth Annual Survey of Football Fatalities. January, 1956. Committee on Injuries and Fatalities, American Football Coaches Association. Dr. Floyd R. Eastwood, Chair- man. Twenty-Fifth Annual Survey of Football Fatalities. January, 1957. DeHaven, H. "Injuries," War Medicine, 2:582-588,Aug.,l95A. Gurdjian, E. S., 33 31. "Quantitative Determination of Acceleration and lntercranial Pressure in Experimental Head Injury," Neurology, 3:6:Al7-A23, June, 1953. Gurdjian, E. S. and J. E. Webster. "Recent Advances in the Knowledge of the Mechanism, Diagnosis, and Treatment of Head Injury," American Journal of the Medical Sciences, 226:214-20, August, 1953. Gurdjian, E. S., J. E. Webster, and H. R. Lissner. "Obser- vations on the Mechanism of Brain Concussion, Con- tusion, and Laceration," Surgery, Gynecology, and Obstetrics, 101:680-90, December, 1955. Gurdjian, E. S., g: 31. Studies on Experimental Concussion. Wayne University Neurosurgical Service, March, 195A. Gurdjian, E. S., J. E. Webster, and H. R. Lissner. "Obser- vations on Prediction of Fracture Site In Head Injury," Radiology, 60:2:226-35, February, 1953. Gurdjian, E. S., J. E. Webster, and H. R. Lissner. "The Mechanism of Skull Fracture," Radiology, 5A:3:313-39, March, 1950. ”Hendler, Edwin and Commander Edward Wurzel. "The Design and Evaluation of Aviation Protective Helmets,” The Journal of Aviation Medicine, 27:1:6A—70, Feb— ruary, 1956. ‘Hawk, G. Kenneth. Football Injuries Survey for 1952 Season. Houghton, Michigan: Michigan College of Mining and Technology, March, 1953. 63 Hawk, G. Kenneth. Football Injuries for 1953 Season. Houghton, Michigan: Michigan College of Mining and Technology, March, 195A. Lissner, H. R., E. S. Gurdjian, and J. E. Webster. "Mechan- ics of Skull Fracture," Experimental Stress Analysis. Report from Wayne University and Grace Hospital, May,1950. Lombard, Charles F. "How Much Force Can Body Withstand,” Aviation Week, 50:3:20-28, January 17, l9A9. Lombard, Charles F., e: 31. "Voluntary Tolerance of the Human to Impact Accelerations of the Head," The Journal of Aviation Medicine, 22:2:109-16, April, 1951. "New Helmet Protection Theory Advanced," Aviation Week, 50:A:18-20, January 2A, 19A9. Protection, Incorporation, 6521 West Blvd., Inglewood 3, California. Personal correspondence dated June 1, 1956. Strand, 0. T. "Protective Helmet Impact Testing Equipment," Air Force Technical Report No. 5820, May, 1949, p.179. Strand, 0. T. "Impact Effect on Two Types of Protective Helmets," Air Force Technical Report No. 6020, May, 1950, Index iii. White, William H. "Armor That Does As Much Harm As Good," Sports Illustrated, October 31, 1955, pp. A6-A7. "‘ p0 w"-a I I F m firs-53:2: '- a .1 u. “Fl. LLIQ‘II Erwin“ rwém5wK1 h ...;E a" I APPENDIX 65 MH620 Calibration l mil/CM = .23 Position G's Cal and Setting Readings Average at 1 Velocity mil/CM Front 6 PF7§Eb 2 mil/CM 3.5 3.1 3.3 3.8 3.9 3.52 30.6 9 5 3.6 4.4 5.2 5.2 4.6 100.0 12 10 2.5 3.4 2.6 3.6 4.2 3.26 141.7 15 20 3.4 2.9 3.3 3.1 1 7 3.08 267.8 18 20 3.8 .6 4.5 4.6 - 4.375 380.4 21 20 3.8 5.4 5.4 5.1 5.6 5.06 440 Back 6 ft/Sec 2 mil/CM 3.4 3.4 3.7 3.3 3.1 3.38 29.4 9 5 1.9 1.9 1.8 2.0 1.9 1.9 41.3 12 5 351 2.6 3J2 3.6 3g3 3.16 68:7 15 5 lst off 3.6 4.0 4.0 2.8 3.6 156 5 10 rest 18 20 ' 4.0 4.2 4.3 4.4 4.4 4.26 370.4 21 20 1st -- 2.4 2.1 2.0 2.4/ 2.24 486.9 .05 volt/CM 2.3 Right Side 6 ft/Sec 2 mil/CM 3.5 3.6 3.7 3.0 3.8 3.52 30.6 9 5 2.6 2.7 2 8 2.7 2 6 2.68 71.3 12 5 3.4 5.6 -— 5.9 -- 4.97 108. 15 10 lsttwo 5.0 5.6 2.8 2.8 2.7/ 5.3/' 224.3 20 rest 2.0 2.58 18 20 3.6 3.9 4.1 4.0 4.4 4.0 ' 347.8 21 05 volt/CM 2.1 2.1 2.0 2.2 2.2 2.12 460.9 292 » 6 ft/sec 2 mil/CM 2.3 2.2 2.4 2.6 2.8 2.46 21.4 9 2 3.9 3.7 4.0 3.6 3.8 3.8 33.0 :12 2 1st 4.7 2.3 1.9 2.1 2.1/ 2.08 45.2 5 rest _ 2.0 15 5 3.1 3.0 3.0 3.0 3.5 3.12 67.8 :18 5 lst off 3.3 3.7 3.8 3.3- 3.525 153.3 10 rest 21 20 3.2 3.8 3.2 3.7 3.4 3.46 300.9 In...‘ ‘u.._ . I. ' q . am... v. ... ...... m. 4 .a t. C: ... . .... ... «4... .. . r; "NU r. . I . . x- n. n .d I. . . 43 . . I 2 ..J .i frv by pH. : {rad . a z ., fry 9 .C [C On: «.7. ... a 4.0 5. IL Cd; ,. .. .1/5 . .1 .11 . l .I. HE D; 4 a .. «\d ..H. u I . .. . I a a . . rhu nUJ 2:1nfiu w L awari 1i 11*er 66 S3131 Calibration 1 mil/CM = .23 Position G's Cal and ' Setting Readings Average at 1 Velocity mil/CM 31:92.: 6 ft/sec 2 mil/CM 3.6 3.7 4.6 3.5 3 7 3.82 33.2 9 5 2.4 2.8 2 4 2 3 -- 2.475 53.8 12 5 4.4 4.2 -- -- 4.8 4.47 97.2 15 10 3.3 4.1 4.6 4.8 5.4 4.44 193.0 18 20 3.4 3.3 3.4 4.2 3.8/ 3.7 321.7 4.1 21 .05 volt/CM2.2 2.1 2.0 2.1 1.8 2.04 443.5 1.3.221: 6 ft/sec 2 mil/CM 4.1 3.9 4.6 4.6 4.2 4.28 37.2 9 5 2.4 2.5 2.5 2.7 —- 2.525 54.9 12 5 3.1 3.0 3.2 3.1 3.2 3.12 67.8 15 10 1.9 2.0 2.2 1.9 2.0 2.0 87. 18 10 2.3 2.9 3.5 3.2 2.4 2.86 124.3 21 10 lst off 3.8 1.3 3.9 3.7/ 3.18 276.5 20 3.2 Right Side 6 ft/Sec 2 mil/CM 3.1 3.4 3.5 3.3 3.5 3.36 29.2 9 5 2.0 2.0 2.2 2.2 2.2 2 12 46.1 12 5 3.0 3.2 2.9 2.9 2.7 2 94 63.9 12 10 1.8 2.0 1.8 1.8 1.9 1.86 80.9 18 10 2.3 2.4 2.3 2.2 2.3 2.3 100.0 21 10 3.4 3.4 3.4 3.8 4.0 3 6 156.5 222 6 ft/Sec 2 mil/CM 2.3 2.1 2.0 2.0 2.4 2.16 18.8 9 5 1.5 1.4 1.3 1.5 1.4 1.42 30.9 :12 5 1.8 1.5 1.5 1.4 1.7 1.58 34.3 15 5 159 230 2A) 1.9 2x1 1.96 42.6 18 5 2A) 2.9 2L3 333 2.9 2.72 59.1 21 10 for 4 1.4 2.0 5.1 5.4 2.0/ 3.475/ 161.2 20 rest 1.3 1.97 " 2. ' . a . g 3.5'11'56 .{F'j—Jv-Lm I; . a a . . .. s . .. . x . . .'- km . t. 5'. _' I l " 67 RK-RKA Calibration 1 mil/CM = .23 Position . G's Cal and Setting Readings Average at 1 Velocity mil/CM Front 6 ft/sec 2 mil/CM 3.5 3.0 3.1 3.2 3.1 3.18 27.7 9 5 2.6 3.0 2.8 2.7 2.8 2.78 60.4 12 5 4.4 4.0 4.1 4.6 3.7 4.16 90.4 15 10 2.9 2.4 3.0 2.2 2.4 2.58 112.2 18 10 1st 5 2.0 1.7 2.2 1.5/ 1.93 167.8 20 rest 1.7/ 2.5 21 20 3.8 3.5 3.9 3.4 3.2 3.56 309.6 Back 6 ft/sec 2 lst 4.9 1.7 1.9 1.8 2.0/' 1.84 40 5 rest 1.8 . 9 5 2.8 2.9 2.6 2.9 2 8 2.8 60.9 12 5 3.6 4.0 3.7 3.6 -- 3.725 80.98 15 5 4.3 4.7 4.4 4.8 4.4 4.52 98.3 18 10 ' 2.8 2.9 2.5 2.6 2.7 2.70 117.4 21 10 for 3 4.1 o f off 3.7 4.6/ 4.375 380.4 20 rest 5.1 Right Side 6 ft/sec 2 mil/CM 2.4 2.4 3.5 2.5 2 9 2.74 23.8 9 2 4.9 4.8 4.5 5.3 -- 4.875 42.4 12 5 2x7 2L5 2.6 2L7 2J4 2.58 56.1 15 5 2.8 2.9 3.0 3.1 2.9 2.94 63.9 18 5 3.2 3.2 3.2 3.2 2.9 3.14 68.3 21 5 lst 4.0 5.0 off 0 r 4.7/ 4.6 200.0 10 rest 3.4/ 5.9 29.2 6 ft/sec 2 mil/CM 3.9 3.9 3.6 3.8 3.2 3.68 32.0 9 5 2.3 2.2 2.3 2.2 1.9 2.18 47.4 12 55 2.8 2L9 2&3 2x7 2.6 2.76 60A) 15 10 1.8 1.7 1.7 1.7 1.7 1.72 74.8 :18 10 1.7 1.9 1.9 1.9 1.9 1.86 80.9 21 10 2.2 2.5 3.0 3.3 3.3 2.86 124.3 Wit-1'. . 68 Dfli6l2 Calibration 1 mil/CM = .23 Position G's Cal and Setting Readings Average at 1 ‘Velocity mil/CM Front 6 ft/sec 5 mil/CM 1.4 1.6 1.4 1.6 1.6 1.52 32.6 9 10 .8 .9 1.0 1.2 1.0 .98 42.6 12 20 15 20 Inability to accurately 1.8 20 measure pip 21 20 Back 6 ft7sec 5 mil/CM 1.0 1.0 1.0 1.0 .8 .96 20.9 9 , 5 1.6 1.8 1.7 1.8 1.9 1.76 38.3 12 10 -— 1.6 1.1 1.4 1.5 1.4 60.9 15 20 Inability to accurately 18 20 measure pip 21 .05volts CM - 1.2 .9 .9 1.1 1.025 222.8 Right Side 6 ft/Sec 5 mil/CM .7 .7 .7 .6 .7 .68 14.8 9 5 1.1 1.2 1.2 1.1 1.2 1.16 25.2 12 5 15 5 Inability to accurately 18 5 measure pip 21 10 Top 6 ft7sec 2 mil/CM 2.8 2.5 2.7 2.5 3.0 2.7 23.5 9 2 4.3 3.6 3.8 3.4 3.775 32.8 12 5 1.9 1.8 1.9 2.0 2.0 1.92 41.7 15 5 2.6 2.3 2.4 2.4 2.5 2.44 53.0 18 5 4.0 4.3 5.3 4.6 4.55 98.9 21 5 1st off off 2.8 2.8 2.3/ 2.725 236.96 10 2nd 3.0 20 rest 69 .23 Calibration 1 mil/CM mu 8 m 1 e H n“ Qo mm m . m l a C1 St I a G e 00 a “1 e V A S g n .l d a e R Go n .1 t t e S n O .l td in 3a 0 P mil/CM Velocity 16 5935 17 5311“ 20) 5798 5 23 7 47 KO.I4.11 21 2324. // .4 7784 51 48 r0328 21 2324 536 7 21 o o ‘0 21 2.24 78 54.0.0. 21 .2324. 31 08.4.0.an 25 232...?) M” C / t 1Pt S .10 S e mfl r. 22 55500 11 C e S / t f 69 2581 111 a Back 3 6821 7 0 9429 5 3 35/01 9 1 2 331221314 .4 74.8/fl 3 3 1223 4 5 0.r0.0.2 5 53 2.232 3 2 7.8800. 7 3 1222 1 26 Rianmu .4 3 1230 3 M“ C / t 1 .CS .1 SE m 1? 2 5r325500 12 C e S / t n1 6 9258 1 111 2 Right Side ...... ...... ...... 4.2 R/3JIQJ o/R/ ron4RX8 2L4 510717. .41 4487 3.2 2111 40 5.481 32 2112 51 7786 32 2111 31 7680 35 2112 M” C / t Its .189 m1r. 2255000 111 C e S 01/ 0t Tf 69 2581 1112 7O wF2010 Calibration 1 mil/CM =.23 Position G's Cal and Setting Readings Average at l Velocity mil/CM Front / A 6 8 8 o ft7sec 2 mil CM 1.9 2.0 2. 2.5 2.0 2.1 l . 9 2 1.1 1.4 1.2 4.2 5.0 u.38 38.1 12 5 3.2 3.2 3.0 2.7 3.3 3.08 66.95 15 10 2.7 3.5 3.0 3.u 3.6 3.24 1uo.9 18 20 3.0 3.1 3.3 2.9 2.8 3.02 262.6 21 20 1.0 u.2 u.3 u.1 u.0 4. 2 358.3 2225 6 ft/sec 2 mil/CM 2.5 2.3 2.0 2.4 2.3 2.3 20.0 9 2 3.7 3J4 u-8 313 1.4 b.02 3u.96 12 5 lst -- 2.8 2.1 2.2 2.u 2.375 103.3 10 rest 15 20 1.5 2.3 2.u 2.6 2.6 2.28 198.2u 18 20 3.7 3.7 3.9 3.7 3.6 3.72 323.5 21 20 0.2 u.0 4.3 u.6 1.5 u.32 375.7 Right Side 6 ft/sec 2 mil/CM 2.3 2.1 1.7 2.0 2.3 2.08 18.1 9 5 1.3 1.2 1.4 1.3 1.1 1.32 28.7 12 5 1.5 1.u 1.5 1.6 1.4 1.48 32.2 15 5 21. 2.0 213 2J2 2.2 2.16 u6.96 18 5 lst -- 3.0 2.6 2.7 3.u/ 3.08 133.9 10 rest 3.7 21 20 3.1 3.0 3.3 -- 3.2 3.15 273.9 222 6 ft/éec 2 mil/CM 2.0 2.6 2.0 2.0 2.0 2.12 18.u 9 2 3.4 3.u 3.2 3.2 3.3 3.3 28.7 12 5 2.1 2.0 2.0 2.1 2.0 2.0a uu.3 15 5 u.1 3.8 4.0 u.5 ,u.2 u.12 89.6 18 10 lst 5.6+ 3.4 3.4 3.8 3.5/ 3.54 307.8 20 rest 3.6 21 20 u.6 u.7 5.0 4.5 1.5 u.66 u05.2 71 S3122 Calibration 1 mil/CM = .23 Position G's Cal and Setting Readings Average at 1 Velocity - mil/CM Front 6 ft/sec 2 mil/CM 2.3+ 2.2 2.3 2.1 2.3 2.24 19.5 9 2 3.8 3 0 3.5 3.5 3.2 3.4 29.6 12 5 4.4 —- 2.7 4.2 3.6/ 3.84 83.5 .3 . 15 10 3.2 3.8 1.1 1.2 2.2 2.3 100.0 18 10 4.7 3.1 3.3 4.1 4.1 3.86 167.8 21 20 3.6 3.7 3.9 3.6 4.0 3.76 326.96 Back 6 ft/sec 2 mil/CM 2.4 2.8 2.3 2.7 2.5 2.54 22.1 9 2 3.7 4.0 -- 3.8 3.5 3.75 32.6 12 5 1.8 2.0 1.7 1.7 1.8 1.8 39.1 15 5 lst -- 3.4 3.5 3.5 3.0 3.35 145.7 10 rest 18 20 2.8 3.1 3.0 3.1 3.0 260.9 21 20 4.0 4.1 4.2 4.3 4.3 4.18 363.5 Right Side 6 ft/sec 2 mil/CM 2.1 2.3 2.2 2.1 1.7 2.08 18.1 9 2 3.2 3.0 3.7 3.1 3.6 3.32 28.9 12 5 2.0 2.0 1.9+ 2.1 2.0 2.0 43.5 15 5 2.7 2.5 2.6 2.6 2.5 2.58 56.1 18 10 1.8 1.7 1.7 1.7 1.7 1.72 74.8 21 10 1.8 1.7 1.7 1.9 1.6 1.76 76.5 $212 6 ft/sec 2 mil/CM 2.0 1.8 2.1 2.0 2.0 1.98 17.2 9 2 3.0 3.1 3.2 3.4 3.0 3.14 27.3 12 5 1:7 118 113 1.8 137 1.76 38.3 15 5 2.3 2.6 2.4 2.4 2.0 2.34 50.9 18 5 lst off 3.4 4.2 4.0 4.%/ 4.06 176.5 10 rest 4. . 21 10 1st off 4.5 4.0 4.3 4.6/ 4.38 380.9 20 rest 4.5 72 .23 G's Cal at 1 mil/CM Average Calibration 1 mil/CM -_— Readings 1. 3. 4. M Setting 20 for 2 .05 volts/C Back And Velocity ME610 [Second Run] Position 8 4 9073 5 20311 /0 23469 5 l 5 8.284 21122 93 212222 8 002 m2 . 232 211022h4 35 M C 2 / 1 t .l S m 1 25552500 11 C e S // t n1 6 Right Side 331212 74 0 5500 Top 24 4.4832 892212757 224422211 3534322211 60930 2557 233422211 775022857. 224422211 892533867 334422211 dtdtdt nSHSHS 212121 / 1M .1 mC 00 2 2 5 511 C e S / t f 6 9 2 5001 1 112 . 4: .23 G's Cal at 1 mil/CM Average Calibration 1 mil/CM = Readings mil/CM 2.6 4. Setting 2 lst 5 rest 2 Front 6 ft/sec 9 and Velocity WF2000 [Second Run] Position ..... M C / t 1 S 1 1 m BFJOO .2 11 C .K % C/ a t B oi KOO/258 111 238.3 2.74 2.8 ...... 3.1 2.2 2.7 20 rest 20 Top 6 ff7§ec 21 Right Side 2. 02 2 555 21 x. .... \5 I1 :4 F ..p . . . Dy, . 1. .fi 5 v A IHK. 1v. 4. .....u, mum... ,R30M9fl3fi3&NLY Demco-293