ASTM D Standard Test Method for Random Vibration Testing of Shipping Containers has been released. It revises and replaces the. This standard is issued under the fixed designation D ; the number immediately 1 This test method is under the jurisdiction of ASTM Committee D10 on. ASTM D Standard Test Method for Random Vibration Testing of Shipping Containers.
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Creating a Random Vibr A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. Such tests may be used to assess the performance of a container with its interior packing and means of closure in terms of its ruggedness and the protection that it provides the contents when subjected to random vibration inputs.
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. Current edition approved Oct. Originally published as D Proposal P Last previous edition approved in as D — For the purposes of this test method, the bandwidth may be considered equivalent to the frequency resolution of a spectrum analysis.
Two PSD levels that have a ratio of 2. Two PSD levels that have a ratio of 0. Power spectral density is the limit of the mean square amplitude in a given rectangular band divided by the bandwidth, as the bandwidth approaches zero. The instantaneous amplitudes of a random vibration are prescribed by a probability distribution function, the integral of which over a given amplitude range will give the probable percentage of time that the amplitude will fall within that Copyright?
Random vibration contains no periodic or quasi-periodic constituent. In the exclusive case of a sine wave, the rms value is 0. For drive clipping at the 3 sigma level, the maximum amplitude will not exceed 3 times the rms value.
The number of DOF is determined by the analysis bandwidth frequency resolution and total time of the sample determined by frequency resolution and number of averages. In terms of a vibration system, it is the ratio of output response to a constant input over a de?
ASTM D Random vibration test_百度文库
Approximating the actual damage, or lack of damage, experienced in real life may require subjecting the container and its contents to random vibration tests. In this way, many product and container resonances are simultaneously excited. Therefore, unrealistic fatigue damage due to resonance buildup is minimized. Refer to Practice D for recommended random vibration tests. See Appendix X1 and Appendix X2 for related aastm. Equivalent tests between sine and random, in a general sense, are difficult to establish due to nonlinearities, damping and product response characteristics.
This test allows analysis of the interaction between these components. However, different test levels may be utilized for each axis depending on the?
The vibration table shall be supported by a mechanism capable of producing single axis vibration inputs at controlled levels of continuously variable amplitude throughout the desired range of frequencies. The controller automatically generates equalized vibration test system drive signals to achieve the desired PSD thus maintaining closed loop control.
The equalized drive signals automatically compensate for specimen and vibration test system characteristics. Typical systems 4d728 an analog to digital converter for conditioning feedback signals, a digital to analog converter to produce drive signals, a digital processor with real time analysis capability, random vibration control software programs, a graphics display terminal, printer, and a data storage unit. NOTE 2—Random vibration systems astj create a drive signal that follows the Gaussian distribution.
Instrumentation may also be desirable for monitoring the response of the test specimen s. Therefore, fences, barricades, and other restraints must have sufficient strength and must be adequately secured.
Stop the test immediately if a dangerous condition should develop. Blemished or rejected products may be used if the defect will not affect test results and if the defect is documented in the report. Dummy test loads are acceptable if testing the actual product might be hazardous or cost prohibitive.
ASTM-D – Medical Package Testing
Axtm a dummy load is used, an assessment must be made, after the test is completed, as to whether or not the actual test item would have passed or failed.
Sensors and transducers should be applied with minimum possible alteration of the test specimen to obtain data on the container or packaged item.
When it is necessary to observe the contents during the test, holes may be cut in noncritical areas of the container. Calibration and Standardization 8. Field measurements must be accurately recorded with equipment having adequate frequency response and dynamic range to prevent attenuation or noise contamination of the acceleration energy levels.
This data must then be reduced to PSD format and equalized for proper control of the vibration system In the absence of speci? Therefore, control analysis based on monitoring table motion rather than actual package response is recommended.
This table feedback signal is generated by an accelerometer mounted directly to the table. Accelerometer mounting location should be next to the d47288 specimen or directly below it on the underside of the table.
Very steep slopes require smaller bandwidths to maintain control to 63 dB. When no conditioning requirements are given, and the container materials are climatically sensitive, a conditioning atmosphere is recommended see Practice D for standard and special conditions.
The specimen center of gravity should be as near as practicable to the center of the table.
Unit loads, stacked columns, or aastm units should be allowed to vibrate freely unless they will actually be securely fastened during shipment, crates on s4728 When the specimen is not secured to the table, restraining devices should be attached to the vibration table to prevent potential movement of the specimen off the vibration table.
Adjust the restraining devices to permit free movement of the specimen of approximately 10 mm 0. This is important since random vibration will produce relatively large, low frequency displacements in an unpredictable sequence. This enables the closed loop control system to complete its equalization at lower test levels and provides the operator adequate opportunity to visually verify that the test specimen and?
D47228 test duration is the time at full test level. Time spent during start up is not included.
Any attempt to do so should be done with caution. For example, if the laboratory test e4728 not produce a realistic level of damage, then adjustments should be made. Precision and Bias Exact situations must be veri? The user of random vibration must verify accuracy and applicability of any data of this type prior to its use.
These sample test pro? They do not purport to accurately describe a speci? This actual data, from Ref 7represents a leaf spring trailer with a 40 lb 18 kg load traveling at 55 mph on a concrete interstate expressway. These samples are from Refs. Forest Product Laboratory, ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
Users of this standard d472 expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are d4278 their own responsibility.
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