Environmental test and reliability test are different.

Posted On：2016-08-04

Environmental test and reliability test although closely related, but they in test purpose, environment stress quantity and environmental forces value selection criteria, test type, test time and test termination criterion there are distinct differences.
Objective test:
Environmental test is the product of the adaptability of the environment, to determine whether the product's environmental adaptability design meets the requirements of the contract, to accept, reject to provide a basis for decision-making. The reliability test is a quantitative assessment of the reliability of the product, that is, the product in the specified environment, the provisions of the time required to complete the function of the probability.
Environmental stress quantity:
Is environmental testing, GJB 150 provides 19 pilot projects, mil-std-810 D provisions of the 20 items of environmental tests and 810f increased to 24 pilot projects, including of product is an important environmental impact of stress. Such as: temperature, wet Ba, salt spray, vibration and shock, pressure, solar radiation, sand and dust, rain. Test items should be selected according to their future use of environmental conditions and the degree of impact on the test items, the general should be more than 10 environmental stresses. The reliability test for the comprehensive simulation, only the comprehensive environmental stress (temperature, humidity, vibration) and the combination of electrical stress test. Obviously, the environmental stress of reliability test is much less than that of environmental test.
Selection criteria of environmental stress value:
The extreme conditions are used in environmental testing, and the most extreme environmental conditions that may be encountered in the life cycle are used as the test conditions. A lot of experiments with a certain damage and the test process generally do not need to simulate the working state of the product. Reliability test is the main environmental condition and its dynamic process, which is used to simulate storage, transportation and use. In GJB-889 and the corresponding D MIL-STD-781 provides a set of mission profiles to determine the environmental profile, and then the environmental profile is simplified as the test section of the product for a long time reliability assessment method. The reliability test is generally not to cause damage, it is needed to simulate the working status of the product, often encountered by most of the simulation experiment in mild stress environment, environmental testing is much lower than the value.
Test type:
Environmental tests are usually used single factor test and multi factor combination test, which can be used in a certain order. Reliability test is more comprehensive stress test, the multiple environmental stress in the same space, at the same time applied to the sample, the more realistic simulation of the impact of the use of environmental conditions. In order to improve the accuracy of test results, reliability, test environment also began to focus on the development of comprehensive test, actively developing and applying the temperature, humidity, vibration, radiation, dust, wind and rain and so on stress of large multifunctional environmental testing equipment.
Test time:
In the test environment, each test of time depending on the selection of test and the concrete test procedure, just because its were performance testing time required and make the difference between, test time than reliability test much shorter. The reliability test time depends on the reliability index value and the selection of the test plan and the quality of the product itself. Its time can not be determined, the total number of units to be tested products reached a specified value or can be made to accept, reject the decision so far.
Test termination criterion:
Environmental test is not allowed to fail, the product is a failure, it is considered to pass the test, the test is to stop and failure analysis, to take corrective measures to improve the design. This is the TAAF process of environmental testing. Reliability test is a test of the results of a certain statistical probability, according to the reliability of the contract requirements of quantitative indicators and the selected statistical scheme to determine the number of faults allowed. The test must be carried out to the required number of units to be stopped. Failure reporting, analysis and corrective action system should be established throughout the test.