According to the national standard GB/T2424.11, the purpose of broadband random vibration testing is to determine the ability of components and equipment to withstand random vibrations at specified levels of severity. This indicates that random vibration testing is suitable for components and equipment that might be affected by random vibration environmental conditions during use. The aim of the test is to identify mechanical weaknesses and/or determine if performance degrades below acceptable levels, and to use this information, in conjunction with relevant specifications, to decide whether the test sample passes or fails.
Random vibration simulation tests are not limited to just simulating broadband random vibrations but also include simulations of broadband random + fixed-frequency sinusoidal vibrations, broadband random + narrowband random vibrations, and broadband random + narrowband swept sine vibrations.
Random vibration testing can be applied in the following types of product tests:
- Functional Testing: This test evaluates the product’s functionality and performance degradation under the most severe vibration conditions expected during its environmental life cycle. The conditions for functional testing are typically the maximum possible vibration levels encountered in the field during the product’s life cycle. The product’s basic performance indicators are checked before and after the test, and its fundamental functions are monitored throughout the test.
- Environmental Adaptability Testing: This test is used to verify if the product can operate normally under external environmental conditions. Considering safety factors, environmental adaptability tests are similar to vibration functional tests in that they use the maximum environmental levels expected during the product’s life cycle as test conditions, with sufficient duration to complete functional checks. However, there are differences:
a) If safety factors are not considered, the working conditions for environmental adaptability tests should be typical operational levels within the product’s life cycle.
b) If assessing the cumulative effects of vibration along with environmental factors such as temperature, humidity, altitude, or EMI/EMC is necessary, all environmental adaptability test items should be conducted using the same test product. - Durability Testing: This represents an accelerated fatigue test that simulates the product’s entire life cycle. It uses environmental levels higher than those in functional testing for “accelerated testing” to simulate fatigue damage equivalent to that experienced by the equipment, focusing on structural damage and fatigue. However, the accelerated levels should account for nonlinear effects (e.g., friction wear, thermal effects), as excessively high levels of acceleration can reduce the reliability of test results.