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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Quality Foam can fabricate our foams to your exact specifications, whether working from our own in-house design or customer-supplied drawings. Tp 5 maximum shock test machine pulse duration in ms, and f c 5 component natural frequency in Hz.
When possible, analyze the data for normality reasonable conformance with Gaussian probability distribution.
Acceptable increment size is in? Under all three methods, the test product is fastened to the carriage of a shock test machine.
For the same reason, waveforms having faired shapes that are not trapezoidal should not be used for this test. In addition, Test Methods D and E also describe this procedure.
It is important to keep damping values the same throughout all portions of the procedures described below. This is sufficient to characterize and indicate the signi? Government Printing Office,pp.
ASTM D Standard for Mechanical_百度文库
A superscript epsilon e indicates an editorial change since the last revision or reapproval. This is required to avoid the rounded intersection of the critical velocity change and critical acceleration lines.
D Terminology of Packaging and Distribution Environments. Unit or consumer packages, which are transported within an outer container, are considered to be the product for the purposes of these test methods.
Such a factor will vary widely for different types of products. Two test methods are outlined, as follows: Failure occurred in the seventh test, establishing the vertical critical velocity change line midway between the sixth and seventh test levels see 9. A 2 ms duration pulse can be used on a component with a natural frequency up to 83 Hz. The shock input for each test is thus determined by the previous test result. That is, it may be possible to design the cushion to transmit a somewhat higher acceleration yet still not cause damage to the product.
The damage boundary of a trapezoidal-shock pulse envelops damage boundaries produced by other waveforms. Unit or consumer packages, which are transported within an outer container, are considered to be the product for the purposes of these test methods.
Shock pulses having values outside the shaded area will not damage the product. Drop height control shall be provided to permit reproducibility within 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.
Site design by Softnet. Method B is used when drop heights are known with great certainty. Shock pulse waveform is not limited since the critical velocity portion of the damage boundary is unaffected by shock pulse shape.
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 procedure of A4. The machine is set to attain a velocity change which exceeds the minimum required to damage the product, but at a very low acceleration level.
For a given product, the interrelation of these three parameters is shown by damage boundary, as plotted in Fig.
Two test methods are outlined, as follows:. A product usually has a different critical acceleration for each direction in which it is tested.
On the basis of much testing experience, it has been determined that rise and fall times see Fig. Even though the product may be a prototype, additional sub-elements are frequently available to replace the one that was damaged. Historical Version s – view previous versions of standard. If the component natural frequency is higher, the pulse duration must be shorter. For a product d3332 this type, it is important to determine the probable number of shocks that it will be subjected to in shipment.
Calculation that assumes the shock pulse to be a perfect geometric? Damage can render the product unacceptable because it becomes inoperable or 3d332 to meet performance speci? An SRS plot is a graph of the absolute value of the maximum response accelerations of each spring-mass system, plotted at their various natural frequencies. D332 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. Then, when the carriage is dropped, the product is examined for product damage. A factor of 2 or more is normally used for an added safety margin. Although a true square wave shock pulse is most desirable in theory, it is not possible to obtain in? The SRS of the shock pulse transmitted by the cushioning need only lie below Sc in a frequency range of approximately 1?
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. Multiple samples of such a product are usually tested.