ASTM D3332-99
(Test Method)Standard Test Methods for Mechanical-Shock Fragility of Products, Using Shock Machines
Standard Test Methods for Mechanical-Shock Fragility of Products, Using Shock Machines
SCOPE
1.1 These test methods cover determination of the shock fragility of products. This fragility information may be used in designing shipping containers for transporting the products. It may also be used to improve product ruggedness. Unit or consumer packages, which are transported within an outer container, are considered to be the product for the purposes of these test methods. Two test methods are outlined, as follows:
1.1.1 Test Method A is used first, to determine the product's critical velocity.
1.1.2 Test Method B is used second, to determine the product's critical acceleration.
1.2 The values stated in either inch-pound or SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 6.
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Designation: D 3332 – 99
Standard Test Methods for
Mechanical-Shock Fragility of Products, Using Shock
Machines
This standard is issued under the fixed designation D 3332; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Measure of Quality for a Lot or Process
E 680 Test Method for Drop Weight Impact Sensitivity of
1.1 These test methods cover determination of the shock
Solid-Phase Hazardous Materials
fragility of products. This fragility information may be used in
designing shipping containers for transporting the products. It
3. Terminology
may also be used to improve product ruggedness. Unit or
3.1 Definitions—General definitions for packing and distri-
consumer packages, which are transported within an outer
bution are found in Terminology D 996.
container, are considered to be the product for the purposes of
3.2 Definitions of Terms Specific to This Standard:
these test methods. Two test methods are outlined, as follows:
2 2
3.2.1 acceleration of gravity (g)—386.1 in./s (9.806 m/s ).
1.1.1 Test Method A is used first, to determine the product’s
3.2.2 critical acceleration (A )—the maximum-faired accel-
c
critical velocity change.
eration level for a minimum velocity change of 1.57 DV (see
c
1.1.2 Test Method B is used second, to determine the
9.3), above which product failure (or damage) occurs. A
product’s critical acceleration.
product usually has a different critical acceleration for each
1.2 The values stated in either inch-pound or SI units are to
direction in which it is tested.
be regarded as the standard. The values given in parentheses
3.2.3 critical velocity change (V )—the velocity change (see
c
are for information only.
9.2) below which product failure is unaffected by shock-pulse
1.3 This standard does not purport to address all of the
maximum-faired acceleration or waveform. A product usually
safety concerns, if any, associated with its use. It is the
has a different critical velocity change for each direction in
responsibility of the user of this standard to establish appro-
which it is tested.
priate safety and health practices and determine the applica-
3.2.4 damage—product failure that occurs during a shock
bility of regulatory limitations prior to use. For specific
test. Damage can render the product unacceptable because it
precautionary statements, see Section 6.
becomes inoperable or fails to meet performance specifications
2. Referenced Documents when its appearance is unacceptably altered, or some combi-
nation of these failure modes occurs.
2.1 ASTM Standards:
3.2.5 damage boundary—See Annex A3.
D 996 Terminology of Packaging and Distribution Environ-
2 3.2.6 fairing—The graphical smoothing of the amplitude of
ments
a recorded pulse still containing high frequency components
D 2463 Test Method for Drop Impact Resistance of Blow-
3 even though electronic filtering may have been performed.
Molded Thermoplastic Containers
This amplitude is used to evaluate the basic recorded pulse
D 3580 Test Method for Vibration (Vertical Sinusoidal Mo-
2 features with respect to the specified pulse. (see Figs. A1.1 and
tion) Test of Products
A2.1)
D 4332 Practice for Conditioning Containers, Packages, or
2 3.2.7 shock pulse programmer—a device used to control the
Package Components for Testing
parameters of the acceleration versus time shock pulse gener-
D 5112 Test Method for Vibration (Horizontal Linear Mo-
ated by a shock test machine.
tion) Test of Products
3.2.8 shock test machine drop height—the distance through
E 122 Practice for Choice of Sample Size to Estimate a
which the carriage of the shock test machine falls before
striking the shock pulse programmer.
1 4. Significance and Use
These test methods are under the jurisdiction of ASTM Committee D-10 on
Packaging and are the direct responsibility of Subcommittee D10.15 on Fragility
4.1 These test methods are intended to provide the user with
Assessment.
data on product shock fragility that can be used in choosing
Current edition approved April 10, 1999. Published June 1999. Originally
published as D 3332 – 88. Last previous edition D 3332 – 98.
Annual Book of ASTM Standards, Vol 15.09.
3 4
Annual Book of ASTM Standards, Vol 08.02. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3332–99
optimum-cushioning materials for shipping containers or for 7. Sampling
product design modification.
7.1 Sampling procedures and the number of test specimens
depend on the specific purposes and needs of the testing.
5. Apparatus
Sample size determination based on Practice E 122 or other
established statistical procedures is recommended.
5.1 Shock Test Machine:
5.1.1 The machine shall consist of a flat horizontal test
8. Conditioning
surface (carriage) of sufficient strength and rigidity to remain
flat and horizontal under the stresses developed during the test. 8.1 If temperature and humidity conditioning is required for
The test surface shall be guided to fall vertically without the product being tested, refer to Practice D 4332 for standard
rotation or translation in other directions.
conditioning procedures. Unless otherwise specified, conduct
5.1.2 The machine shall incorporate sufficient carriage drop all tests with the same conditions prevailing.
height to produce the shock pulses given in 9.2 and 9.3. Drop
9. Procedure
height control shall be provided to permit reproducibility
within 60.25 in. (66 mm).
9.1 Mount the product to be tested on the carriage of the
5.1.3 The machine shall be equipped to produce shock
shock test machine. The product should be supported by a
pulses at the carriage as specified in 9.2 and 9.3.
fixture similar in shape and configuration to the cushion that
5.1.4 Means shall be provided to arrest the motion of the
will support the product in its shipping container. The fixture
carriage after impact to prevent secondary shock.
should be as rigid as possible so as not to distort the shock
5.2 Instrumentation: pulse imparted to the product. Fasten the fixture and product
5.2.1 Acceleration— An accelerometer, signal conditioner,
securely to the carriage so that it will not leave the surface of
and data storage apparatus are required to record acceleration- the carriage during the shock test.
time histories. The accelerometer shall be attached rigidly to
NOTE 1—The points at which the fixture supports the product are very
the base structure of the product or to the fixture, at or near a
important because the dynamic response of the product is influenced
point at which the fixture is fastened to the carriage. If the
strongly by the location of these support points
fixture is sufficiently rigid to not distort the shock pulse
NOTE 2—If the orientation of the product can change during handling
imparted to the product, the accelerometer may be mounted on impacts, a test may be required for each of the directions in which the
input shock can occur. Multidirectional tests are recommended since most
the carriage. In some cases, when a product contains heavy
products have different fragilities in different orientations.
resiliently supported masses that will distort the shock pulses
severely, it may be necessary to precalibrate the shock ma-
9.2 Test Method A—Critical Velocity Change Shock Test:
chine. The accelerometer is fastened to the carriage in this case, 9.2.1 Scope—This test method is used to determine the
and a rigid mass weighing the same as the product is subjected
critical velocity change ( V ) portion of the damage boundary
c
to a series of shock pulses. The instrumentation system shall plot of a product.
have sufficient response to permit measurements in the follow- 9.2.1.1 To ensure that the components of a product only
ing ranges. respond to the velocity change of the pulse, a shock pulse
having any waveform and a duration (T ) not longer than 3 ms
5.2.1.1 Test Method A— 5 Hz or less to at least 1000 Hz.
p
5.2.1.2 Test Method B— 1 Hz or less to at least 330 Hz. should be used to perform this test. Pulse durations as short as
0.5 ms may be required when testing small, very rigid products
5.2.1.3 Accuracy—Reading to be within 65 % of the actual
value. (see Note 3). Shock pulse waveform is not limited since the
critical velocity portion of the damage boundary is unaffected
5.2.1.4 Cross-Axis Sensitivity—Less than 5 % of the actual
by shock pulse shape. Since they are relatively easy to control,
value.
shock pulses having a half sine shock waveform are normally
5.2.2 Velocity—Instrumentation to measure the velocity
used.
change of the shock table is required. This may be a device that
integrates the area electronically under the shock pulse wave-
NOTE 3—In general: T # 167 / f
p c
form. Alternatively, it can be measured by photodiode-type
where:
devices that measure shock table impact and rebound velocity.
T = maximum shock test machine pulse duration in ms, and
p
Calculation that assumes the shock pulse to be a perfect
f = component natural frequency in Hz.
c
geometric figure is usually grossly inaccurate and should not be
For example, a component of a product with a natural frequency below
used.
56 Hz can be effectively tested on a shock machine witha3ms duration
pulse. If the component natural frequency is higher, the pulse duration
6. Precautions
must be shorter. A 2 ms duration pulse can be used on a component with
a natural frequency up to 83 Hz.
6.1 These test methods may produce severe mechanical
responses in the test specimen. Operating personnel must 9.2.2 Procedure:
therefore remain alert to potential hazards and take necessary 9.2.2.1 Set the shock test machine so that the shock pulse
safety precautions. The test area should be cleared prior to each produced has a velocity change below the anticipated critical
impact. The testing of hazardous material or products may velocity change of the product.
require special precautions that must be observed. Safety 9.2.2.2 Perform one shock test.
equipment may be required, and its use must be understood 9.2.2.3 Examine or functionally test the product, or do both,
before starting the test. to determine whether damage due to shock has occurred.
D3332–99
9.2.2.4 If no damage has occurred, set the shock test able increment size is influenced strongly by the product being
machine for a higher velocity change and repeat the shock test. tested. For example, an increment of 5 g may be appropriate for
Acceptable increment size is influenced strongly by the product most products but unacceptable for high-value products.
being tested. For example, an increment of 5 in./s (0.13 m/s)
NOTE 4—See shock machine manufacturer recommendations for set-
may be appropriate for most products but unacceptable for
ting acceleration levels because this procedure is specific to the type of
high-value products.
programmer.
9.2.2.5 Repeat 9.2.2.2-9.2.2.4, with incrementally increas-
9.3.2.6 Repeat 9.3.2.2-9.3.2.5, with incrementally increas-
ing velocity change, until product damage occurs. This point is
ing maximum-faired acceleration, until product damage oc-
shown as Test No. 7 in Fig. A3.1.
curs. This point is shown as Test No. 14 in Fig. A3.1. Common
9.2.2.6 Common practice is to define the critical velocity
practice is to define the critical acceleration (A)asthe
c
change (V ) as the midpoint between the last successful test and
c
midpoint between the last successful test and the test that
the test that produced failure. Depending on the purpose of the
produced failure. Depending on the purpose of the test, use of
test, use of the last successful test point before failure may be
the last successful test point before failure may be considered
considered as a more conservative estimate of (V ).
c
as a more conservative estimate of (A ).
c
9.3 Test Method B—Critical Acceleration Shock Test:
9.3.1 Scope—This test method is used to determine the
10. Report
critical acceleration ( A ) portion of the damage boundary plot
c
10.1 Report the following information:
of a product.
10.1.1 Reference to these test methods, noting any devia-
9.3.1.1 When the critical acceleration of a product is known,
tions from the test method.
package cushioning materials can be chosen to protect it.
10.1.2 Complete identification of the product being tested,
9.3.1.2 If no cushioning materials are to be used in the
including type, manufacturer’s code numbers, general descrip-
package, it may be unnecessary to perform this test. Only the
tion of configuration, and its pretest condition.
critical velocity change test may suffice in this case.
10.1.3 Method of mounting the product on the carriage of
9.3.1.3 Trapezoidal shock pulses are normally used to
the shock test machine.
perform this test. Although a true square wave shock pulse is
10.1.4 Type of instrumentation used and critical settings
most desirable in theory, it is not possible to obtain infinitely
thereof.
short rise and fall times. On the basis of much testing
10.1.5 Recordings of the shock pulses that caused product
experience, it has been determined that rise and fall times (see
damage.
Fig. A2.1) of 1.8 ms, or less, are required. Longer rise and fall
10.1.6 Record of shock test machine drop height for each
times cause the critical acceleration line of the damage
shock pulse that caused product damage.
boundary curve to deviate from the horizontal, introducing
10.1.7 Record of damage, including a photograph of prod-
errors into the test results. For the same reason, waveforms
uct damage, if visible.
having faired shapes that are not trapezoidal should not be used
10.1.8 Record of waveform, maximum-faired acceleration,
for this test. Their use would cause the critical acceleration line
pulse duration, and velocity change of the shock pulses.
of the damage boundary curve to vary widely as a function of
10.1.9 Record of conditioning used.
velocity change. For example, if a half sine shock pulse
10.1.10 Plots of damage boundaries of the product.
waveform is used, a deeply scalloped critical acceleration line
10.1.11 If multiple products are used, record of the sampling
is produced and the test data become meaningless.
methods, average or median test levels, and standard devia-
9.3.2 Procedure:
tions.
9.3.2.1 Set the shock test machine so that it will produce a
trapezoidal shock pulse having a velocity change of at least
11. Precision and Bias
1.57 times as great as the critical velocity change determined in
11.1 Precision—The within-laboratory or repeatabi
...
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