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JEIBRAR Y 293 10533 9372
Michigan State
University

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This is to certify that the

thesis entitled

SHAPES OF SHOCKS IN SHOCK ENVIRONMENT
WITH TELEMENTRY SHOCK MEASURING
SYSTEM

presented by

HIROYUKI IWASHIMIZU

has been accepted towards fulfillment
of the requirements for

M.S . . PACKAGING
degree 1n

%Mss wfifl

Major professor

 

 

Date May 15, 1978

 

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SHAPES OF SHOCKS IN SHOCK ENVIRONMENT
WITH TELEMENTRY SHOCK MEASURING

SYSTEM

BY

Hiroyuki Iwashimizu

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

School of Packaging

1978

ABSTRACT

SHAPES OF SHOCKS IN SHOCK ENVIRONMENT
WITH TELEMENTRY SHOCK MEASURING
SYSTEM

BY

Hiroyuki Iwashimizu

The shocks encountered in the package were not
measured sufficiently because of unavailability of
self-contained, compact and accurate instrumentation.
This thesis deals with the shapes of such shocks measured
in the package. A telementry shock measuring system was
designed for this testing. Four aspects of shock
environments in the distribution system were chosen as
simulated shock environments, such as 42" One Man Drop,
One Man Throwing, Dr0p from Stack, and Dr0p onto Other
Packages.

From the testing, triangular, half-sine, parabolic
cusp, complex cusp, two-peak, trapezoidal, and other
complex shapes were obtained.

As a "dummy" product, ll 3/8 lbs. of the
telementry system instrumented wood block was used.
Two-hundred pound test C-flute corrugated paperboard was
used for the container, in which the wood block and

cushion were packaged.

ACKNOWLEDGMENTS

I wish to express my sincere appreciation for the
guidance and support given in this research by Dr. James
W. Goff, professor of School of Packaging at Michigan
State University.

I also wish to extend my appreciation for the help
and support to members of my committee, Dr. Hugh E.
Lockhart, professor of School of Packaging and Dr. George
W. Wagenheim, assistant professor of Marketing at

Michigan State University.

ii

TABLE OF CONTENTS

LIST OF TABLES . . . . . . . . . . . .
LIST OF FIGURES . . . . . . . . . . .
INTRODUCTION . . . . . . . . . . . .
Purpose . . . . . . . . . . . . .
Method . . . . . . . . . . . . .
Background . . . . . . . . . . . .
TELEMETRY SHOCK MEASURING SYSTEM . . . . . .
Total System Description . . . . . . .
Instrumented Package Description . . . .
SHAPE OF SHOCK . . . . . . . . . . . .
Effect of Shock Shape . . . . . . . .
Typical Shock Shape and Average Acceleration
SIMULATED ENVIRONMENT DESCRIPTION . . . . .
42" One Man Drop . . . . . . . . . .
One Man Throwing . . . . . . . . . .
Drop from Stack . . . . . . . . . .
Drop onto Other Packages . . . . . . .
SHOCK ENVIRONMENT TEST PROCEDURE . . . . .
42" One Man Dr0p . . . . . . . . . .

One Man Throwing . . . . . . . . . .

iii

vi

IH P' F4 id

10
IO
12
14
14
16
16
16
16
l7

l7

Drop from Stack . . . . . . . . . .

Drop onto Other Packages . . . . . . .

RESULTS AND DISCUSSION . . . . . . . . .

42" One Man Drop . . . . . . . . . .

One Man Throwing . . . . . . . . . .

Dr0p from Stack . . . . . . . . . .

Drop onto Other Packages . . . . . . .

Summary . . . . . . . . . . . . .

CONCLUS IONS O O O O O O O O O O O O O

APPENDICES . . . . . . . . . . . . .

A.

B.

C.

D.

Telemetry System Calibration . . . .

Procedure for Determining Damage
Boundaries . . . . . . . . . .

Pulse Weighing Method for Velocity Change

Mathematical Expression of Shock Pulses .

LIST OF EFEMNCES O O O O C O O O O 0

GENERAL REFERENCES . . . . . . . . . .

iv

33
34

35

45
47
48
49

52

Table

LIST OF TABLES

Readings of Shocks in Figure 10 .
Typical Shocks from Test Environment
Calibration of Telemetry Wood Block

Discriminator Output for Different
Frequency Input . . . . . .

Total System Calibration of Channel
Total System Calibration of Channel

Total System Calibration of Channel

38

4O
42
43
44

Figure

10

11
12

13

14

15

LIST OF FIGURES

Total View of Telemetry Shock Measuring
System with Instrumented Package . . .

Telemetry Shock Measuring System Diagram .

Three Components of the Telemetry
Instrument Package . . . . . . . .

Telemetry Instrumented Wood Block . . .

Shock Pulses from Side 2, End 2 and Side 3
on Scope Screen . . . . . . . . .

Damage Boundary Curve . . . . . . .
Typical Shock Shapes and Their Average
Acceleration Ratios (Fractions of their
Peak Accelerations) . . . . . . .
Test Shock Enviroments . . . . . . .
Top View of Boxes for Drop onto Other
Packages Test with DrOp Position of
Test Package (broken lines) . . . . .

Typical Shock Pulses from 42" One Man Drop
Test and Input Directions . . . . .

Triangular Pulse from 42" One Man DrOp Test

Parabolic Cusp and Half-Sine Pulse from One
Man Throwing Test . . . . . . . .

Triangular and Complex Pulse from One Man
Throwing Test . . . . . . . . .

Complex Cusp Pulses and Half-Sine Pulse
from One Man Throwing Test with Wall . .

Complex Cusp Pulse from One Man Throwing
Test 0 O O O O O O O O O O 0

vi

11

13
15
19

20
22

24
24
25

25

Figure
16

17

18

19
20

21

22

23

24

25

26

27
28

Pulses with Two-Peaks from One Man

Throwing Test . . . .

Triangular Pulses from Drop from Stack Test

Triangular and Complex Pulses from Drop

from Stack Test . . .

Triangular Pulse from Drop from Stack Test
Half-Sine Pulse from Drop from Stack Test

Parabolic Cusp Pulse from Drop from Stack

Test C O I C O C .

Trapezoidal Pulse with 32.5 ms Duration from

Drop on a Box . . . .

Trapezoidal Pulse with 5.0 mx Peak Duration

from Drop on Four Boxes .

Half—Sine Pulses from Drop on Other Packages

Test 0 O O O O O 0

Complex and Two-Peak Pulse from Drop on

Other Packages Test . .

Calibration of Telemetry Wood Block on Shock

Machine with Gas Programmer
Brief Structure of Coupler

Damage Boundary Determination

vii

26

26

27
27

27

28

29

29

30

30

37
42

46

INTRODUCTION

Pur EC 86

The purpose of this paper is to measure the
shocks which a product would encounter in the package in
the simulated shock environment by the telementry shock
measuring system and to examine the shocks and their

shapes.

Method

The telemetry system was built in a wood block in
which three accelerometers were mounted triaxially. It
was packaged in a corrugated paperboard container with a
cushion and dropped in the simulated shock environments.
The shocks were recorded on oscilloscopes and pictures
were taken. The shapes of the shocks were observed, and
the average accelerations were calculated from the
durations and velocity changes of the shocks for

reference.

Background

 

For the design of more SOphisticated protective

packages, the distribution environment, the performance

characteristics of cushioning materials and the determi-
nation of product fragility are studied in the field of
packaging.

The distribution environment has two aspects,
i.e., the in-transit environment and the handling environ-
ment. The in-transit environment includes those motions
resulting from movement on transport vehicles (trucks,
railroads and aircraft). The handling environment
includes those motions resulting from operations such as
physical handling, loading and unloading, and movement
within storage or warehouse areas (1) The in-transit
environment was well studied compared to the handling
environment. Ostrem (2) presented the frequency spectra
measurements and the probability occurrence of acceler-
ations from in-transit environments. Sharpe, Kusza and
Goff (3) analyzed the vibration environment in common
carrier trucks for the vibration testing of packages and
indicated that the accelerations of shocks from the
environment were not nearly as high as would be
experienced in a drop test. Ostrem and Rumerman
presented comprehensive literature surveys and searches
for the in-transit environment (4) in 1965, and the
handling environment (1) in 1967. In the latter survey
the handling environment was described in dr0p heights,

number of drops during the shipment of packages and so on.

This distribution environment data has been reflected in
package shock and vibration testing programs.

The performance characteristics of cushions have
been studied since the time of Mindlin's research (5).
The static stress versus peak acceleration characteristics
was employed and standardized package cushioniong (6).
In determination of the shock fragility of products,
the characteristics of shocks imposed on the products are
important. With different shapes of pulses, shocks and
the effects of shocks on product fragility were investi-
gated, and the impact sensitivity curve (7) and the
damage boundary curve (8) were introduced theoretically.

Nevertheless, the shocks experienced by products
in packages in the distribution environment have not been
measured due to the unavailability of an accurate
self-contained instrumentation capable of measuring the
shocks. This thesis deals with the shapes of the shocks
of this sort, transmitted through a cushion and a con-
tainer from simulated shock environments. To c0pe with
the instrumentation problem, a telemetry shock measuring
system was developed by Goff and Pierce (9). Based on
the telemetry system, a new one was designed and built in

a wood block as a “dummy" product for this testing.

TELEMETRY SHOCK MEASURING SYSTEM

Total System Description

 

The FM/FM telemetry shock measuring system had a
frequency response from 1 to 2100 Hz and a shock response
from 10 to 95 g's. The calibration procedure is shown in
Appendix A.

The total View of the system is shown in Figure l.
The package contains the instrumented wood block or test
product. The system is comprised of three, single
channels. Three receivers are shown on the right-hand
side of Figure 1. Each channel consists of an acceler-
ometer, a coupler, an attenuator, a voltage controlled
oscillator (VCO), a transmitter, a receiver, a discrimi-
nator and a recording device as shown in Figure 2 (8).
The operation of a single channel is briefly described
here, and the other channels operate in the same manner.

The shock received by the test product in the
package is measured by an accelerometer in voltage as a
shock pulse. This is once amplified by a coupler and
attenuated to fit the input voltage for a VCO. The VCO
changes a voltage signal to a frequency signal. The
frequency signal is sent on a radio frequency carrier

from a transmitter to a remote receiver. The receiver

4

 

 

Figure 1. Total View of Telemetry Shock Measuring System
with Instrumented Package

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retrieves the original frequency from the radio frequency.
The discriminator converts the frequency signal to the
initial voltage signal, the shock pulse. The pulse is

monitored on a recording device.

Instrumented Package Description

 

The instrumented package consists of three
components; the telemetry wood block, the cushion and the

container as shown in Figure 3.

 

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Figure 3. Three Components of the Telemetry
Instrumented Package

The telemetry wood block is instrumented with the
telemetry shock measuring system in its wood body. The
shocks received by this wood block in the package were
sent to remote receivers and recorded. This wood block
is divided into two parts. One is the inner block, in

which the telemetry system is directly housed and the

other is the outer block, in which the inner block was
enclosed from top and bottom (see Figure 4). Honduras
mahogany wood was used for the body of the block, and its
outer dimensions were 8 x 8 x 8 inches. The size of the
inner block was 5 1/4 x 4 5/8 x 2 1/8 inches. To give
orientation to the telemetry wood block, its two ends and
four sides were numbered. Referring to the bottom block
in Figure 4, the end shown in contact with the floor is
designated as end 2, and the opposite end is designated as
end 1. Side 1 is the front side of the block, and side 2
is the right-hand side of the block. Side 3 is opposite
side 1, and side 4 is opposite side 2. End 2, side 3

and side 2 are the bottom sides of the three accelero-
meters. If a shock is sensed from those ends or sides,
_the corresponding pulses appear as positive pulses on an

oscilloscope screen as shown in Figure 5.

 

 

Figure 4. Telemetry Instrumented Wood Block

 

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Figure 5. Shock Pulses from Side 2, End 2
and Side 3 on Sc0pe Screen

For the cushion, Ethafoam* with density of 2.2
pounds per cubic feet was used. In terms of thickness,
3/4 inches was chosen to protect the wood block and the
accelerometers of which the maximum input limits was
250 9'3. The cushion was slipped in every corner and
side of the block in the container.

The container was made of 200 pound test C-flute
corrugated paperboard with the inside dimensions of
9 1/2 x 9 l/2 x 9 l/2 inches. Also, its type was a
regular slotted box. For the manufacturer's joint and
the tOp and bottom seals, Scotch brand tape, No. 351-2

was employed.

 

*Trademark of the Dow Chemical Company

SHAPE OF SHOCK

Effect of Shock Shape

 

A shock is specified by three characteristics,
such as its duration, acceleration and shape. These
characteristics can be described by the shock pulse,
which is the acceleration time history of the shock.

With their pulses, shocks have been studied in their
severity on shock sensitive products or spring-mass
system models.

Kornhauser showed experimentally that no damage
occurs until both a critical value of acceleration and a
critical value of \relocity change are exceeded (7). The
same idea was introduced by Newton (8) as the damage
boundary concept, that is, a product is subject to damage
under any shock in the shaded area of its damage boundary
curve as shown in Figure 6. The damage boundary curve is
determined by a shock machine drop test (see the procedure
in Appendix B).

The vertical line of the damage boundary curve is
independent of the shape of the shock, however, the
horizontal line is a function of the shape of the shock.
Consequently, the type of shocks measured in this testing

concern the horizontal line area. The pulses on the

10

ll

horizontal line have a long duration, and a short
duration on the vertical line. Also, the average
acceleration is important in the horizontal area, since

this concerns the minimum acceleration required to cause

/// W
”/2

VELOCITY CHANGE

damage.

ACCELERATION

 

 

 

Figure 6. Damage Boundary Curve

The average accelerations of the shocks in the
testing were calculated from the velocity change (AV),
which was determined by the pulse weighing method (see
Appendix C). With the AV and Duration, the Ave.-g is
calculated as follows:

Ave.-g = AV
D x 386:4

where Ave.-g = the Average Acceleration (in/secz),
AV = the Velocity Change (in/sec),

the Duration (sec).

and D

12

Typical Shock Shapes and Average
Acceleration

 

 

Typical shock shapes and their average
accelerations are shown in Figure 7. The average values
are the fractions of their peak accelerations. The
calculations were made based on the mathematical
expressions of the pulses (11) shown in Appendix D.

The rectangular pulse only has an average
acceleration equal to its peak acceleration. In
practical shock machine testing, trapezoidal pulses
are used as rectangular pulses because of mechanical
limitations. The half-sine pulse has 64% of the peak
acceleration for the average acceleration. The average
acceleration of the haversine pulse is 50% of its peak.
Different shapes of triangles have equal average
acceleration if the duration and peak acceleration are
equal. However, it should be noticed that even if the
accelerations are the same, the differences in shape
will affect the vertical line (7) of the damage
boundary curve shown in Figure 6. The parabolic cusp
has the lowest average acceleration; 33% of the peak
acceleration. Usually, the cusp is produced from
bottoming of the cushioning materials or from the
impact of rigid bodies.

With the average acceleration, the pulse
shapes are sorted for the results. The half-sine pulse

and haversine pulse were regarded as a half-sine pulse.

l3

 

 

 

 

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(a) Rectangular

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(c) Harversine

 

 

 

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(e) Parabolic Cusp

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(b) Half-sine

 

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(d) Triangular

 

Figure 7. Typical Shock Shapes and Their Average
Acceleration Ratios (Fractions of Their
Peak Accelerations)

SIMULATED ENVIRONMENT DESCRIPTION

Four shock environments in distribution were
chosen as the test environment, as shown in Figure 8

and explained below.

42" One Man Drop

 

This is a basic aspect of the handling environ-
ment. The test package was held by a man at 42 inches
from a concrete floor and is dropped freely. This height
was chosen because of the total weight of 12 1/2 lbs.
according to the Recommended Drop Height (1). (This is
about the distance from the floor to the elbows of a man

of average height.)

One Man Throwing

 

This is chosen as another aspect of physical
handling by a man, assuming the situation that small and
light packages are thrown to the floor during loading or
unloading. The package was held at the height of 30
inches and thrown horizontally, approximately seven feet

ahead.

14

15

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1 4. .
30'
777/777”)? 77/ /7t"7—7:Z§’77x

(a) 42” One Man Drop (b) One Man Throwing
T .0»
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(c) Drop from Stack (d) Drop onto Other Packages

Figure 8. Test Shock Environments

l6

Drgp From Stack

 

The package was dropped from the top of a stack
of packages. The five boxes under the test package were
stacked 60 inches high. These are the boxes used in the
one man drop test and the one man throwing test. By
using the used boxes, the stack fell simply by pushing
the package with a finger. This is used in the situation
where the top package falls off due to an inferior (i.e.,

damaged packages on the bottom) stack.

Drop Onto Other Packages

 

The package was dropped flat onto empty corru-
gated boxes from 60 inches above. This situation, where
a package dropped onto other packages, occurs in the
handling environment. In the in-transit environment it
does happen when a package falls onto other packages from

the top of a stack of packages due to vehicle vibration.

SHOCK ENVIRONMENT TEST PROCEDURE

42" One Man Drop Test

 

The package was held at a height of 42" from the
concrete floor with end 2 of the test product facing down
toward the floor and side 3 facing the man. It was
released gently and it dropped freely. A reflex photo-
electric relay and a retro-reflector were set so that when
the package interrupted the light beam between them, the
sweep of an oscilloscope would be triggered. A Tektronix
Model 5643 storage oscillosc0pe was used. The shock
pulses from the test product were recorded on the
oscilloscope and pictures were taken by a Textronix

oscillOSCOpe camer C-12.

One Man Throwing

 

The package was held by a man at a height of 30
inches from the floor with end 2 facing the floor and side
3 facing the direction of throwing. It was intended for
the package to be thrown so that the package wouldn't
rotate more than 90 degrees, or at least, so that end 2
would face the floor at the first impact. The reflex
photoelectric relay and the reflector were set at 1 1/2

inches from the floor and 7 feet from the man. The

17

18

package was sensed by the light beam and the shocks were
recorded on the Tektronix Model 564B storage oscillosc0pe
and pictures were taken by the Tektronix camera C-12. A
Tektronix oscillosc0pe Model 17623 was used supplemen-
tarily. Also, a Honeywell Model 1508 VISICORDER was used
to observe the shocks after the first impact. The
container and cushion were replaced by new ones after six

or seven throws.

Drop From Stack

 

The package was placed on top of five empty boxes
at a height of 60 inches from the concrete floor. Two
used boxes were set on the bottom of the stack so that
the stack would fall down when a small amount of force
was applied to the package. The other three boxes were
the same as the test container. From the initial
observations of the manner in which the stack fell, the
package was found to rotate forward approximately 90
degrees. Therefore, end 2 and side 3 of the package were
set to face forward and downward reSpectively on the
stack so that end 2 hit the floor and side 3 faced
forward at the first impact. This "falling-orientation"
in terms of the first impact was the same as in the One
Man Throwing test.

The photoelectric relay and the reflector were

set to catch the drop of the package. The shock pulses

19

were recorded on the Tektronix 564B storage oscillosc0pe

and pictures were taken by the oscilloscope camera.

Drop Onto Other Packages

The package was held at 60 inches above the top
of empty boxes and drOpped freely onto them. The shock
pulses were monitored by a Tektronix 564B storage
oscilloscope and pictures were taken by an oscilloscope
camera.

Two box configurations are shown in Figure 9. One
is a single box, and the other is a set of four boxes.
These boxes were made of 200 pound test C-flute corru-

gated paperboard.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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- I I : I
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(a) One Box (Height = 9”) (b) A Set of Four Boxes (Height = IO”)

Figure 9. Top View of Boxes for Drop onto Other
Packages Test with DrOp POsition of
Test Package (broken lines)

RESULTS AND DISCUSSION

42" One Man Drop

Shown in Figure 10 are typical pulses resulting
from a 42" one man drop test and their input directions
to the test product, indicated by side- and end- numbers.
This numbering is held constant throughout this thesis
unless indicated. An example interpretation of the

result follows.

Triangular I

“k. fl\‘;n/c‘?}im
/
‘ /

 

Figure 10. Typical Shock Pulses from 42" One
Man Drop Test and Input Directions.

In the middle of Figure 10, a triangular pulse,
numbered I, is recognized, implying that the shock at the
first impact was mostly input to end 2 since the deflec-

tion of the sweep for end 2 is larger than any other
20

21

pulses in the figure. The damped vibration on the bottom
was began at the same time as the other triangular pulse
II on side 1. This vibration means that the test product
was excited by the shocks from side 1 and side 3 alter-
nately. In other words, the package was dropped flat and
end 2 hit the floor first, but, at the same time, side

3 hit it slightly. As a result, the test product inside
the package started fluctuating between side 1 and side

3 while the main force was imposed on end 2. Little
shock was recorded on side 2 and side 4. Channel 3 for
these directions showed malfunctions, therefore, it was
neglected thereafter. The package did not turn over after
the first impact. In Table l, readings of shocks in

Figure 10 are shown.

Table l. Readings of Shocks in Figure 10

 

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Peak-g 42 g's peakég 20 g's
Duration 9.0 ms Duration 6.5 ms
AV 81 in/sec AV 26 in/sec
Ave.-g 23 g's Ave.-g 10 g's
Ave.-g/Peak-g .55 -- Ave.*g/Peak-g .50 --

 

The peak-g (peak acceleration in g's) and duration
of the triangular pulse I can be read as 42 g's and 9.0 ms

respectively. Its velocity change (AV) and average-g

22

(average acceleration in g's) were calculated as 81 in/sec
and 23 g's respectively. The duration of a pulse is the
duration at the 10% level of its peak acceleration. The
ratio of the average-g over the peak-g, expressed here as
Ave.-g/Peak—g, was .55. This pulse is classified as a
triangular pulse due to its shape, even though it has a
high value of Ave.-g/Peak-g for a triangular pulse. The
triangular pule II has 20 g's of a peakeg, 6.5 ms of a
duration, 26 in/sec of a velocity change, and 10 g's of
an average acceleration. The ave.-g/Peak-g value was .50.
In Figure 11, another result from the 42" One Man
Drop Test is shown. The shape is designated as a
triangle due to its ratio of Ave.—g/Peak-g. The average
acceleration was 27 g's, while the peak acceleration was

54 g's.

 

Figure 11. Triangular Pulse from 42" One
Man Drop Test.

23

One Man Throwing

 

More complicated shock shapes and a variety of
shock shapes were obtained from the One Man Throwing
Test because of itsrough motion or rotation of the
package on the concrete floor.

A parabolic cusp pulse and a half-sine pulse are
shown in Figure 12. This parabolic cusp pulse is a
typical cusp and has a very high peak acceleration and a
low average acceleration. The Ave.-g/Peak-g was .23.
The half—sine pulse has the same velocity change of
44 in/sec as the parabolic cusp pulse and a lower peak
acceleration, however, it has a higher average acceler-
ation because of the shape. This half-sine pulse was the
second impact from the rotation of the package on the
floor.

In Figure 13, a triangular pulse and a complex
pulse are shown. The triangular pulse has a higher peak
acceleration than that of the complex pulse, although it
has a lower average acceleration. This complex pulse
could be classified as a half-sine pulse, considering
the value of Ave.-g/Peak-g.

A comparison is made between a complex cusp pulse
on side 1 and a half-sine pulse on side 3 in Figure 14.
The pulse on end 2 is also a complex cusp pulse at the
impact on the floor. It should be noted that the half-

sinie pulse on side 3 was caused when the package was

24

thrown and hit the wall of the steel table unintention-
ally. It was the first throwing after renewing the
cushion and container. The same type of cusp pulse was
obtained on end 2 in other throws with a used package as

shown in Figure 15.

mflf-EUE

36 g's

 

Figure 12. Parabolic Cusp and Half—sine Pulse from One
Man Throwing Test

Trimxnflar Cbmpha:

32 g's 28 g‘s
10 us 9.5 ms

64 in/sa: 65 hykmc
17 g's 18 g's
.52 - .63 -

 

Figure 13. Triangular and Complex Pulse from One Man
Throwing Test

 

 

25

amphac mflf—sfiw

24 g's
17. us
101 in/sec

.64 -

 

Figure 14. Complex Cusp Pulses and Half-sine Pulse from
One Man Throwing Test with Wall

 

Figure 15. Complex Cusp Pulse from One Man Throwing Test

In Figure 16, the pulses with two peaks are shown.
Complex motion of the test product is indicated by the

presence of two peaks.

Drop From Stack

The pulses with relatively low accelerations were

obtained from the drop test from a stack of packages,

26

notwithstanding the 60“ height of the stack underneath the
test package.

In Figure 17, two triangular pulses are shown.
They were classified as triangles because of their shapes
and becasue the values of Ave.-g/Peak-g were close to .50.
Another triangular pulse and a complex pulse are shown in
Figure 18. The complex pulse as a .67 value,
Ave.-g/Peak-g. Other pulses are shown from Figure 19 to

Figure 21.

Peflrg's 20 g's 20 g's
10 g's l4 g's

Dnnfifion 11 RB 12 us

AV 49 Jrvsec 54 jn/sec

Awerg 11 g's 12 g's

Awe.1y¢%akrg .57

 

Figure 16. Pulses with Two Peaks from One Man Throwing
Test

 

Figure 17. Triangular Pulses from Drop from Stack Test

27

hvsec
I

 

Figure 18. Triangular and Complex Pulses from Drop From
Stack Test

 

Figure 19. Triangular Pulse from Drop from Stack Test

 

Figure 20. Half—sine Pulse from Drop from Stack Test

28

 

Figure 21. Parabolic Cusp Pulse from Drop from Stack Test

Drgp on Other Packages

 

Shock pulses with a long duration and a flat top
were obtained from the drop test on other boxes.

The duration was recorded as 32.5 ms for the
relatively trapezoidal pulse in Figure 22. The peak
acceleration was 14 g's and 8 g's for the average
acceleration. The package was dropped on the empty box.
Another trapezoidal pulse was recorded in Figure 23.

This drop was made on the center of four empty boxes.
The duration was 18.5 ms and the peak acceleration lasted
for a period of 5 ms at 24 g's.

Half-sine pulses and other complex pulses are

shown in Figure 24 and Figure 25. These pulses also have

a long duration.

29

fhxmezoflkd

14 g's
32.5 ms
101 in/ax

8 's
.58 -

 

Figure 22. Trapezoidal Pulse with 32.5 ms Duration from
Drop on a Box

 

Figure 23. Trapezoidal Pulse with 5.0 ms Peak Duration
from Drop on Four Boxes

30

Half-sine I Half-sine II

16 g's 24 g's
19.0 ms 20.0 ns

77 in/sec 106 in/sec

10 g's 14 g's
.65 - .57 -

 

Figure 24. Half-sine Pulses from Drop onto Other Packages
Test

g's 24 g‘s
ms 18.0 ns
in/sec 92 in/sec
.g's l4 g's

- .55 —

 

Figure 25. Complex and Two-Peak Pulse from Drop on Other
Packages Test

Summary

To summarize the four simulated shock environment
tests, each test is characterized in terms of the shape,
the peak-g, the duration, and the ratio, Ave.-g/Peak-g of
the shock. The typical shock pulses are chosen and shown

in Table 2.

31

 

 

 

Table 2. Typical Shocks from Test Environments
Ave.-g/ From
Shape Peak-g Duration Peak-g Figure
42" One Man Drop
Triangular I 42 g's 9.0 ms .55 10
Triangular 54 g's 8.5 ms .50 11
One Man Throwing
Parabolic Cusp 70 g's 7.0 ms .23 12
Complex Cusp 56 g's 10.0 ms .29 15
Triangular 32 g's 10.0 ms .52 13
Drop From Stack
Triangular II 24 g's 12.5 ms .49 1?
Complex 18 g's 14.5 ms .67 18
Half-sine 58 g's 8.0 ms '.55 20
Drop Onto Other
Packages
Trapezoidal l4 g's 32.5 ms .58 22
Trapezoidal 24 g's 18.5 ms .57 23

 

32

The 42" One Man Drop is characterized by its two
simple triangular pulses. The One Man Throwing is
characterized by sharp peak pulses, such as a parabolic
cusp pulse, a complex cusp pulse, and a triangular pulse.
These pulses have relatively small values of
Ave.-g/Peak-g. The Drop From Stack is characterized by
a variety of shock shapes. The complex pulse has a .67
Ave.-g/Peak-g value. The long duration and high
Ave.-g/Peak-g value characterize the Drop Onto Other
Boxes.

For the 42" One Man Drop, only the triangular
pulses were obtained since the thickness of the cushion
was made as low as possible for the telemetry system

response.

 

CONCLUSIONS

Various shock shapes were obtained from the
simulated test environments with the telemetry shock
measuring system. The shapes obtained were half-sine,
triangular, parabolic cusp, complex cusp, two-peak,
trapezoidal, and other complex shapes.

The durations of the main pulses at the first
impact of each drop ranged from 7.0 ms to 32.5 ms. The
shortest one was from the parabolic cusp pulse from the
One Man Throwing Test and the longest one was from the
trapezoidal pulse from the Drop Onto Other Packages
Test. The accelerations of the pulses were70 g's and

14 g's respectively.

33

APPENDICES

34

APPENDIX A

TELEMETRY SYSTEM CALIBRATION

The components and the total system of the
telemetry measuring system were calibrated. The procedure
followed the Development of the Telemetry Shock Measuring

System (8).

Telemetry Wood Block

 

The shock'transmission of the wood block was
tested. The block was mounted directly on the shock
machine table with a fixture as shown in Figure 26. The
two ends and four sides of the block were tested. Each
test accelerometer in the block was connected to the
oscilloscope through a coupler. Its reading was compared
with the signal from a control accelerometer on the same
scope screen. The control accelerometer was connected
through a coupler. Half-sine pulses were used as
controlled pulses, generated by the shock machine with
the gas programmer or plastic programmers with felt on
them. Pictures of the pulses were taken. The results
are shown in Table 3, indicating no effect on the shock
transmission by the wood block intself and the whole

assembly. The equipment used was a MTS gas programmable

35

36

shock machine, a Kistler 808 accelerometer for control,
three Kistler 818 accelerometers for test, Kistler 5483
couplers for the test accelerometers, a Kistler 587D

coupler for the control accelerometer, a Tektronix 7023

oscilloscope, and Textronix oscillosc0pe camera C-l2.

37

 

 

Figure 26. Calibration of Telemetry Wood Block
on Shock Machine with Gas Programmer

38

Table 3. Calibration of Telemetry Wood Block

 

 

Control Accelerometer Test Accelerometer

Deceleration Duration Deceleration Duration

 

(in g's) (in ms) (in g's) (in ms)

End 1 28 7.6 28 7.6
68 5.5 68 5.5

125 4.0 125 4.0

220 3.6 220 3.6

End 2 28 7.6 28 7.6
70 5.3 70 5.3

125 3.8 125 3.8

220 3.6 220 3.6

Side 2 24 7.6 24 7.6
70 5.4 70 5.4

125 3.8 125 3.8

200 3.5 178. 4.0

Side 4 24 7.6 24 7.6
68 5.6 68 5.6

125 3.8 125 3.8

200 3.5 200 3.5

Side 1 27 8.0 27 8.0
68 5.5 68 5.5

115 3.8 125 3.5

175 4.0 190 3.7

Side 3 28 7.4 27 7.6
68 5.8 68 5.5

125 3.8 125 3.8

175 4.0 175 4.0

 

39

Attenuators

 

The attenuators were designed to reduce the
voltage from the couplers to the voltage controlled
oscillators for their input sensitivity limit. A
combination of SOkQ and lkO registers of 5% tolerance
were used as a voltage divider to provide an attenuation
factor of 50.

A voltage from 0 to 2.5 volts was applied to an
attenuator with a frequency from 0 to 5 KHz. Ths input
voltage and output voltage of the attenuators were read
on the same oscillosc0pe.

As a result, the attenuators had an attenuation
factor of 50 and would not be affected by the frequency
range from 0 to 5 KHz.

The equipment used was; a Hewlett Packard 202C
Low Frequency Oscillator, a Hewlett Packard 5381A 80
Mitz Frequency Counter, and a Tektronix 564 B Storage
Oscilloscope.

VCO, Transmitter, Receiver
Discriminator

 

The VCO, transmitter, receiver and discriminator
were tested together to see the effect of the frequency
on voltage ouput from the discriminator.

A sinusoidal input of 50 millivolts was input to
the VCO and monitored on an oscilloscope. The output

from the discrminator was monitored on the same scope and

40

a voltmeter. The frequency of input was varied from 1 to

2100 Hz. The results are shown in Table 4.

Table 4. Discriminator Output for Different Frequency

 

 

 

Input
Channel 1 Channel 2 Channel 3

Frequency Output Output Output
Input (Hz) (volts) (volts) (volts)

1 2.5 2.5 2.0

50 2.5 2.5 2.0

100 2.5 2.5 2.0

150 2.5 2.5 2.0
200 2.46 2.44 1.96
250 2.44 2.42 1.94
300 2.42 2.38 1.92
350 2.38 2.34 1.90
400 2.38 2.30 1.86
450 2.34 2.26 1.84
500 2.32 2.20 1.78
600 2.24 2.12 1.68
700 2.16 2.00 1.64
800 2.08 1.86 1.64
900 1.98 1.76 1.56
1000 1.92 1.66 1.48
1100 1.84 1.56 1.40
1200 1.74 1.46 1.34
1300 1.66 1.34 1.24
1400 1.56 1.26 1.18
1500 1.48 1.16 1.12
1600 1.40 1.06 1.04
1700 1.30 .98 .98
1800 1.24 .90 .92
1900 1.16 .84 .86
2000 1.08 .78 .80
2100 1.02 .72 .76

 

Channel 3 did not have the correct VCO center

frequency so that the discriminator did not have enough

41

gain. It was set at the maximum 2.0 volts. Bsides that,
each channel had a flat frequency response up to 150 Hz.
The equipment used was; a Hewlett Packard 202C Low
Frequency Oscillator, a Tektronix 564 B Storage Oscillo-
scope, a Hewlett Packard 5381A 80 MHz Frequency Counter,

and a Hewlett Packard 3403C RMS Voltometer.

Total System

 

The telemetry instrumented block (the test
product) was assembled and mounted on a shock machine.
All the ends and sides were tested and with half-sine
pulses from a gas programmer or a plastic programmer with
durations from 3.5 to 7.6 milliseconds.

The shocks were compared with the ones from a
control accelerometer directly mounted on the table of
the shock machine.

Results were shown in Table 5, 6 and 7 for
Channel 1, 2 and 3 respectively and the total system was
calibrated. Channel 1 in Table 5 was calibrated and
capable of measuring up to 170 g's and 95 g's for side
1 and side 3. This was found to be caused by the system
of a battery and a spring of the coupler, since the
direction of the battery and the spring was the same as
the drop directions, side 1 and side 3 as shown in Figure

27.

42

Table 5. Total System Calibration of Channel 1

 

 

Control Accelerometer Test Accelerometer
Deceleration Deceleration
(in g's) (in 9'5)

 

Positive Direction (Side 3)

50 48
90 88
130 128
170 168
190 *

Negative Direction (Side 1)

16 16
52 54
95 98
125 *

 

*Pulses were not obtained.

Coupler Body Spring

 

 

 

 

Figure 27. Brief Structure of Coupler

43

Table 6. Total System Calibration of Channel 2

 

 

Control Accelerometer Test Accelerometer
Deceleration Deceleration
(in g'S) (in 9'3)

 

Positive Direction (End 2)

16 18
4O 4O
72 72
100 100
125 128
150 152
180 180
210 210
230 240

Negative Direction (End 1)

16 17
4O 4O
7O 70
100 96
125 120
150 144
170 170
200 190

230 200

 

44

Table 7. Total System Calibration of Channel 3

 

 

Control Accelerometer Test Accelerometer
Deceleration Deceleration
(in g's) (in 9'5)

 

Positive Direction (Side 2)

10 10
15 15
50 50
9O 90
130 131
160 171

Negative Direction (Side 4)

15 15
50 50
9O 92
125 127
160 162
200 200

230 231

 

APPENDIX B

PROCEDURE FOR DETERMINING DAMAGE BOUNDARES

This procedure to determine damage boundaries (10)

was developed by Goff and Pierce and shown here briefly.

 

Procedure:

1. A test item is fixed on the table of shock machine.

2. A series of rectangular pulses of constant velocity
change and increasing peak acceleration is applied
to the item until damage occurs (see Figure 28).

3. The vertical line is determined by the level, one
drop before the damage, the fourth drop in this
example.

4. A series of half-sine pulses, beginning with a peak
acceleration of two to three times, caused the damage
at step 3 with a small velocity change, is input to a
new item until the damage occurs.

5. The horizontal line is determined by the level, one

drOp before the damge, the tenth drop in this
example.

45

ACCELERATION

 

 

46

////

DAMAGE

// /

" 4
X ’ ® = Damage
$3.

$1

    
 

x = No damage

 

Figure 28.

VELOCITY CHANGE

Damage Boundary Determination

APPENDIX C

PULSE WEIGHING METHOD FOR VELOCITY CHANGE

This is a method to determine the velocity change
by using a photographic copy from an oscilloscope screen,
and this method is effective when the pulse shape is
complicated and other pulses or noises are around the
pulse concerned.

The velocity change will be calculated as follows:

M x D x 386.4

AV = C X W = UA x SD X W

 

C = Conversion factor in (in/sec)/grams,
where W,= the weight of the measured pulse in grams,
M = Magnitude per unit div. in g's,
D = Duration per unit div. in sec.,
UA = the unit area of a section on the copy in
inz.
SD = the Sheet Density of the copy paper in'
and grams/inz.

47

APPENDIX D

MATHEMATICAL EXPRESSION OF SHOCK PULSES

Rectangular;

a = A 0 s t s
Half-sine;

a = A sin (2% 0 s t s
Haversine;

a = %-A [l — cos (3%E)] 0 s t s
Triangular;

a=2A(l-§'-) Osts

a=2A(l-%) —[2-)-<ts
Parabolic Cusp;

a=4A<11;-)2 Osts

a=4A(1—%)2 g<ts

where a amplitude at time t (a = 0 for t > D),
A = maximum amplitude,

and D

pulse duration at zero line.

48

D:

D:

has

U

sac

LIST OF REFERENCES

49

LIST OF REFERENCES

Ostrem, F. E. and Rumerman, M. L., 1967. Transporta-
tion and Handling Shock and Vibration Design
Criteria Manual (NASA MR 1262-2), Marshall Space
Flight Center, Huntsville, Ala.

Ostrem, F. E., 1972. "A Survey of Transportation
Shock and Vibration Input to Cargo." Shock and
Vibration Bulletin, Vol. 42, part 1, pp. 137-151.

Sharpe, W. N., Kusza, T. J. and Goff, J. W., 1973.
Preliminary Measurement and Analysis of the
Vibration Environment of Common Motor Carriers,
Technical Report No. 22, School of Packaging,
Michigan State University.

Ostrem, F. E. and Rumerman, M. L., 1965. Transpor-
tation Shock and Vibration Design Criteria
Manual (NASA MR 1262), Marshall Space Flight
Center, Huntsville, Ala.

Mindlin, R. D., 1945. "Dynamics of Package
Cushioning.” Bell System Technical Journal, vol.
24, pp. 353-461.

Stern, R. K., 1965. "Military Standardization
Handbook - Package Cushioning Design." MIL-HDBK—
304, Department of Defense, Washington, D. C.

Kornhauser, M., 1964. “Inertia Loading." Structural
Effects of Impact. pp. 61-120, Baltimore:
Spartan Books.

Newton, R. E., 1968. Fragility Assessment Theory and
Test Procedure, Monterey Research Laboratory,
Monterey, California.

Goff, J. W. and Pierce, 8. R., 1973. Development of
Telemetry Shock Measuring System. Technical
Report No. 14, School of Packaging, Michigan
State University.

50

10.

ll.

51

Goff, J. W. and Pierce, S. R., 1969. "A Procedure
for determining Damage Boundaries." Shock and
Vibration Bulletin, vol. 40, part 6, pp. 127-131.

Brooks, R. 0., 1966. "Shock Springs and Pulse
Shaping on Impact Shock Machines." Shock and
Vibration Bulletin, vol. 35, part 6, pp. 23-40.

GENERAL REFERENCES

52

GENERAL REFERENCES

Enke, C. G., and Crouch, S. R., 1974. Optimization of
Electronic Measurements, Module 4. California:
W. A. Benjamin Inc.

Foley, J. T., 1969. "Fragility." Panel Discussion.
Shock and Vibration Bulleting, Vol. 40, part 6,
pp. 53-159.

Gruenberg, E. L., 1967. Handbook of Telemetry and Remote
Control, Chap. 6, New York: McGraw-Hill Book Co.

Harris, C. M. and Crede, C. E., ed., 1976. Shock and
Vibration Handbook, 2d ed, New York: McGraw-Hill
Book Co.

Rountree, R. C. and Safford, F. B., 1970. "Fragility."
Shock and Vibration Bulletin, Vol. 41, part 5,
pp. 111-128.

U.S. Department of Commerce (NBS), 1974. Deve10pment of
Performance Standards or Parce Post Packages,
Project No. 4-35711, also Michigan State
University Project No. 3108.

Vigness, Irwin, 1966. "Specification of Acceleration

Pulses for Shock Tests." Shock and Vibration
Bulletin, Vol. 35, part 6, pp. 173-183.

53

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