The temperature (high temperature, low temperature) and vibration (sine) comprehensive test includes two test methods: high temperature/vibration (sine) comprehensive test and low temperature/vibration (sine) comprehensive test. In fact, these two tests are a combination of low-temperature test, high-temperature test, and vibration (sinusoidal) test. The test methods are also based on the above three single test methods. The test principles described are also applicable to comprehensive tests. . In order to facilitate understanding and mastery, this article combines the low-temperature/vibration test and the high-temperature/vibration test.
The purpose and significance of the comprehensive test
Temperature (high temperature, low temperature) and vibration (sinusoidal) comprehensive testing is to provide a standard test procedure to determine the suitability of thermal, non-radiating components, equipment or other products for use, storage and transportation under high temperature/vibration or low temperature/vibration combined conditions sex. The combined effect of temperature and vibration on the test sample can produce the following effects:
(1) Changes in the basic material properties of the test sample caused by high and low temperatures increase the risk of deterioration of the test sample in a vibration environment. If the temperature-induced material change is not a permanent change, the combined effects of temperature and vibration must be used to expose this degradation, including a large number of interconnected materials and test samples including viscous and elastic materials, such as motors and other products. This combined effect is particularly sensitive.
(2) Under extreme temperature conditions, the resonant frequency and vibration transmission characteristics of the test sample and its ancillary equipment will change greatly. For example, this effect is obvious for test samples with anti-vibration devices under low temperature conditions, especially test samples using rubber shock absorbers.
(3) The combined effect of temperature and vibration has a great impact on exposed devices and connecting devices. Therefore, this test is widely used on these devices, such as rockets and related auxiliary parts, to expose problems.
According to the test of heat dissipation test samples in low and high temperature tests, it is stipulated that the influence of “free air conditions” must be simulated, that is, the air movement in an infinite space is only affected by the heat dissipation test sample itself, and the radiant heat of the test sample is completely absorbed by the surrounding air. , and also proposed that it is best to use a non-forced cycle test chamber for testing. However, in the comprehensive temperature and vibration test, a forced circulation test chamber needs to be used to test the heat dissipation test samples. The reason is: in order to remove the heat generated by the vibration table; the air below the test sample cannot circulate, and the vibration table disturbs the free convection of the air in the test chamber. For the test of non-heat dissipation test samples, follow the conventional test procedures.
Before the test sample is subjected to a comprehensive temperature and vibration test, a single sinusoidal vibration and temperature test inspection is performed. This can avoid comparing the same test sample that actually cannot withstand a single environment or loses its ability to work in a single environment. Complex and expensive comprehensive testing.