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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It may also be used to improve product ruggedness.
As more product samples become available, the test results should be re? Since they are relatively easy d33332 control, shock pulses having a half sine shock waveform are normally used. A number in parentheses indicates the year of last reapproval. As you learned earlier, the determination of fragility is the first step in cushion design; without this information, you can’t determine the cushion thickness that will adequately protect your product.
Other items may have more or less variability.
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. This procedure is less accurate than that described in A4. The betweenlaboratory or reproducibility standard deviation was 5. Instead of designing the cushioning to transmit no more than the critical acceleration Ac, design the cushioning such that it transmits a shock pulse with an SRS of less than Sc lies below Sc at every frequency on the SRS plot.
The peak acceleration of this shock pulse will often exceed Ac. Be certain that the velocity change of subsequent shock pulses is maintained at or above the level determined in 9. Pulse durations as short as 0. Common practice is to de? Current edition approved April 10, To avoid inconclusive test results, the critical acceleration test is conducted at velocity changes at least two times the critical velocity change of the product.
ASTM D Standard for Mechanical_百度文库
This may be a device that integrates the area electronically under the shock pulse waveform. Two test methods are outlined, as follows: For example, an increment of 5 g may be appropriate for most products but unacceptable for high-value products. Examples of unpackaged product handling are movement of the?
The accelerometer shall be attached rigidly to the base structure of the product or to the? Shock pulses having values outside the shaded area will not damage the product. Method C is used for relatively rugged low fragility products that f3332 not need cushioning.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. 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 Ac.
ASTM D | Rycobel
For a given product, the interrelation of these three parameters is shown by damage boundary, as plotted in Fig. Complete details and descriptions of SRS may be found in the literature NOTE 1—The points at which the?
If none occurs, the machine is reset for a higher maximum acceleration and the test is repeated at the same drop height. On the basis of much testing experience, it has been determined that rise and fall times see Fig.
A 2 ms duration pulse can be used on a component with a natural frequency up to 83 Hz. In other frequency regions the cushion SRS may exceed Sc.
Two test methods are outlined, as follows:. Damage can render the product unacceptable because it becomes inoperable or fails to meet performance speci? It will fail only when it is subjected to even higher level shocks. Quality Foam can fabricate our foams to your exact specifications, whether working from our own in-house design or customer-supplied drawings.
If zero damping is speci?
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. ASTM D outlines three test methods A-C for determining the fragility of products to be packaged for shipment in the distribution environment.
Zero damping, however, is not possible for real products and systems, although in most actual situations damping is low. Each trapezoidal shock pulse had a faired acceleration level incrementally higher than the previous shock pulse. This is required to avoid the rounded intersection of the critical velocity change and critical acceleration lines. The maximum acceleration at which product damage first occurs is the fragility of the product in the direction tested. None will be more severe than those produced by the trapezoidal shock pulse.
The test data will have to be corrected if signi? Method B is used when drop heights are known with great certainty. The test area should be cleared prior to each impact.