This standard is issued under the fixed designation D ; the 1 These test methods are under the jurisdiction of ASTM Committee D on. ASTM D Standard Test Methods for Mechanical-Shock Fragility of Products , Using Shock Machines. Shock Machine Testing. Shock testing was performed on a shock machine that is in compliance with the following standard: ASTM D −
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ASTM D Standard for Mechanical_百度文库
The betweenlaboratory or reproducibility standard deviation was 5. Zero damping, however, is not possible for s3332 products and systems, although in most actual situations damping is low.
Alternatively, it can be measured by photodiode-type devices that measure shock table impact and rebound velocity. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This is sufficient to characterize and indicate the signi?
Depending on the purpose of the test, use of the last successful test point before failure may be considered as a more conservative estimate of Vc. Failure occurred in the seventh test, establishing the asm critical velocity change line midway between the sixth and seventh test levels see 9.
Government Printing Office,pp.
ASTM D3332 Foam Test Methods
Accept3 able increment size is in? Maximum-faired acceleration level of the? The maximum acceleration at which product damage first occurs is the fragility of the product in the direction tested.
Instead of designing the cushioning to transmit no more than the critical acceleration Ac, design the cushioning adtm that it transmits a shock pulse with an SRS of less than Sc lies below Sc at every frequency on the SRS plot. Each trapezoidal shock pulse had a velocity change of more than two times the critical velocity change Dd3332 determined previously.
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.
Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm.
Since d333 are relatively easy to control, shock pulses having a half sine shock waveform are normally used. If it fails at that shock level, the next specimen is tested at a level that is a? If the product is complex, usually asgm sub-element of the product will fail?
Multidirectional tests are recommended since most products have different fragilities in different orientations. Shock pulse waveform is not limited since the atsm velocity portion of the damage boundary is unaffected by shock pulse shape.
This point is shown as Test No. It will fail only when it is subjected to even higher level shocks. This procedure is repeated for each orientation and each part of the damaged boundary V c and Ac that is of interest. That is, it may be possible to design the cushion to transmit a somewhat higher acceleration yet still not cause asm to the product.
This is because of the differences in pulse shape and characteristics between the fragility test and actual package cushion performance. In addition, Test Methods D and E also describe this procedure. The test surface shall be guided to fall vertically without rotation or translation in other directions.
Therefore, the test in accordance with Test Method B 9. The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. The product should be supported by a? If it passes, the specimen is tested at a shock level that is incrementally higher. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
The values given in parentheses asttm mathematical conversions to SI units axtm are provided d332 information only and are not considered standard. It is important to keep damping values the same throughout all portions of the procedures described below.
ASTM D Foam Test Methods
The instrumentation system shall have sufficient response to permit measurements in the following ranges. Precision and Bias This is required to avoid the rounded intersection of the critical velocity change and critical acceleration lines.
For this reason, shocks transmitted by some cushion materials will be less severe than those produced by the trapezoidal-shock pulse test. For example, a component of a product with a natural frequency below 56 Hz can be effectively tested on a shock machine with a 3 ms duration pulse.
This may be a device that integrates the area electronically under the shock pulse waveform. In some cases, when a product contains heavy resiliently supported masses that will distort the shock pulses severely, it may be necessary to precalibrate the shock machine. A research report5 describes an interlaboratory test program of three types of items in packages for a critical velocity change shock test.
If the component natural frequency is higher, the pulse duration must be shorter. This amplitude is used to evaluate the basic recorded pulse features with respect to the speci? For specific precautionary statements, see Section 6. Even though the product may be a prototype, additional sub-elements are frequently available to replace the one that was damaged. Longer rise and fall times cause the critical acceleration line of the damage boundary curve to deviate from the horizontal, introducing errors into the test results.
A sample of the product was subjected to half-sine shock pulses in accordance with Test Method A. It is the responsibility of the aetm of this standard to establish appropriate safety and health practices d3332 determine the applicability of regulatory ast prior to use. A number in parentheses indicates the year of last reapproval. The repeatability standard deviations were 6. NOTE 4—See shock machine manufacturer recommendations for setting acceleration levels because this procedure is speci?
The values given in parentheses are for information only. Most products are not affected by this multiplicity of tests. Unit or consumer packages, which are transported within an outer container, are considered to be the product for the purposes of these test methods. A 2 ms duration pulse can be used on a component with a natural frequency up to 83 Hz.