IEC 60068-2-64 Vibration Testing
IEC 60068-2-64 Vibration testing
The IEC 60068 test standard demonstrates that specimens subjected to specified random vibration test requirements are adequately resistant to dynamic loads without unacceptable degradation of their functional and/or structural integrity. Wide-band random vibration can be used to identify cumulative stress effects and the resulting mechanical weaknesses and degradation of specified properties. Used to assess the acceptability of samples, this standard applies to samples that may be subjected to vibrations of a random nature caused by transport or operating environments, such as in aircraft, space vehicles and land vehicles.Why perform IEC 60068 Vibration Testing
All products may experience some vibration during their service life due to transportation and transportation. Therefore, a certain degree of vibration testing is valuable.
- IEC 60068-2-6 and IEC 60068-2-64 can be used to evaluate the reliability and performance of products exposed to vibration environments.
- They can be used to evaluate the durability and performance of connectors exposed to harsh conditions such as military, automotive and space environments. During vibration, the connector is monitored intermittently by electrical contact with the special equipment supplied by JOEO.
- Manufacturers can verify the structural integrity of items and identify possible degradation under different vibration conditions.
- Automotive and aerospace suppliers can assess the reliability, durability and performance of their components that withstand strong vibrations during their service life.
- IEC 60068-2-6 and IEC 60068-2-64 can be used to study the structural dynamics of items used in spacecraft projects.
- Testing against these standards simulates the stresses that occur during the life cycle of a product, increasing confidence in its performance and service life.
- The product can function throughout its life cycle and withstand the vibrations it encounters.
- Companies can evaluate the durability and performance of components, equipment and items during transportation and use of vibration.
Equipment test requirements
The required characteristics are applicable to complete vibration test equipment, including power amplifiers, vibrators, test fixtures, specimens and control systems for loading tests.Standardized test methods include the following sequence of tests, usually performed on each axis perpendicular to each other:
An initial vibration response investigation. with low level sinusoidal excitation.l or low level random excitation
The random excitation as the mechanical load or stress test.
Final vibration response investigation to compare the results with the initial one and to detect possible mechanical failures due to a change of the dynamic behaviour
If the dynamic behavior is known and is not considered relevant or sufficient data can be collected at the full level of testing, the relevant specification may not require a new and post-test vibration response investigation.
Transverse motion
If required by the relevant specification, the horizontal axis movement should be checked, sinusoidal or random investigations should be carried out at the level specified by the relevant specification, or tests should be carried out during the test using additional monitoring channels on both vertical axes. The checkpoint ASD value of each frequency on two axes perpendicular to the specified axis shall not exceed the specified ASD value above 500hz and shall not exceed -3 dB of the specified ASD value below 500hz. The total root-mean-square value of the acceleration on two axes perpendicular to the specified axis must not exceed 50% of the root-mean-square value of the specified axisMeasuring systems
The characteristics of the measuring svstem shall be such that it can be determined whetherl the true value of the vibration as measured in the intended axis at the reference point is within the tolerance required for the test. The frequency response of the overall measuring system, which includes the transducer, thel signal conditioner and the data acquisition and processing device, has a significant effect onl the accuracy of the measurements. The freguency range of the measuring system shalll extend from at least 0,5 times the lowest frequency (f) to 2,0 times the highest frequency (fo)l of the test frequency range (see Figure 1). The frequency response of the measuring system shall be flat within ±5 % of the test frequency range. Outside of this range any further deviation shall be stated in the test report.Vibration tolerances
ASD and r.m.s. value
The indicated acceleration spectral density in the required axis at the reference point betweenlf, and f in Fiqure 1 shall be within t3 dB, allowing for the instrument and random error,lreferred to the specified acceleration spectral density.The r.m.s. value of acceleration, computed or measured between f1, and f2, shall not deviatemore than 10 % from the r.m.s. value associated with the specified acceleration spectralldensity. These values are valid for both the reference point and fictitious reference point.At some frequencies, or with large-size or high-mass specimens, it may be difficult to achievelthese values. In such cases, the relevant specification shall prescribe a wider tolerance.The initial slope shall not be less than +6 dB/octave and the final slope shall be -24 dB/octave or steeper (see also B.2.3).
Distribution
The instantaneous acceleration values at the reference point shall have an approximately normal (Gaussian) distribution as given in Figure 2. If explicitly desired, a validation shall bel performed during normal system calibration (see B.2.2).The drive signal clipping shall have a value of at least 2,5 (see 3.16). The crest factor of thel acceleration signal at the reference point shall be examined to ensure that the signal containsl peaks of at least 3 times the specified r.m.s. value, unless otherwise prescribed by the relevant specification.If a fictitious reference point is used for control, the requirement for the crest factor applies to each individual checkpoint used to form the control acceleration spectral density.The probability density function shall be computed for the reference point for a duration of 2 min during testing. The admissible deviation from the normal distribution, Figure 2, shall be prescribed in the relevant specification.
Statistical accuracy
The statistical accuracy is determined from the statistical degrees of freedom Nd and theconfidence level (see also Figure 3). The statistical degrees of freedom are given by:
Frequency resolution
The frequency resolution Be, in Hz necessary to minimize the difference between the true and the indicated acceleration spectral density shall be selected by taking the digital controller frequency range divided by the number of spectral lines (n).
JOEO vibration test table is your first choice for IEC 60068-compliant vibration testing
Choosing the right partner for your shaker table vibration testing needs is critical. At ALI Testing, we offer a full range of services designed to ensure that your products comply with the stringent IEC 60068 standards. Here's why JOEO should be your first choice:
1. Custom solutions: We design and manufacture vibration test fixtures according to your specific needs.
2. Precision and care: Our test setup process is meticulous, including control and response accelerometer placement, correct bolt torque application, and organized cable routing.
3. Quality Assurance: As an accredited laboratory, we comply with IEC 60068-2-6 and IEC 60068-2-64 testing standards to ensure quality and compliance.
4. Advanced facilities: We have the most advanced test facilities and equipment to meet various vibration test requirements.
5. Extensive experience: Our team has extensive experience in vibration testing, including products used in outer space, rockets, missiles, car and truck environments, military environments, and medical environments.
6. Contact JOEO today to discuss your vibration test requirements with our experts.
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