Difference between environment and reliability test

Although environmental tests and reliability tests are closely related, there are diametrically different differences in the test objectives, the number of environmental stress applied, the selection criteria of environmental strength values, the type of test, and the test time.

Test purposes:

The environmental test examines the adaptability of the product to the environment, determines whether the product's environmental adaptability design meets the contract requirements, and provides decision-making basis for receiving and rejecting. Reliability test is a quantitative evaluation of the reliability of products, that is, the probability that the product will complete the specified function within specified time under the specified environmental conditions.

The number of environmental stresses used:

As far as environmental testing is concerned, 19 test items are stipulated in GJB150, and 20 environmental test items are stipulated in MIL-STD-810 D. 810F is added to 24 test items, including environmental stress, which is more important to products, such as temperature, humidity, salt fog, vibration impact, pressure, too solar radiation, sand dust, rain and so on. The test products should be selected according to their future environmental conditions and the extent of their impact. Generally, more than 10 environmental stresses should be investigated. Because of the comprehensive simulation of the reliability test, the comprehensive environmental stress (temperature, humidity, vibration) and electrical stress should be combined to carry out the test. It can be seen that the number of environmental stresses selected in reliability tests is much less than that in environmental tests.

Criteria for selection of environmental stress values:

The extreme conditions are used in environmental tests, instead of mild ones, which are the most extreme environmental conditions that may be encountered during the life cycle. Many tests are destructive and generally do not need to simulate the working state of the products. The reliability test adopts the actual effect test, that is, to simulate the main environmental conditions and their dynamic changes in the process of storage and transportation. In GJB-889 and corresponding MIL-STD-781 D, a set of methods to determine the environmental profile according to the mission profile, and then to simplify the environmental profile into the test section, are presented for the long term reliability assessment of the products. Reliability test generally does not cause damage to the product. It needs to simulate the working state of the product. The test conditions used in most simulation work often encounter a more moderate stress environment, and the value is much lower than that of the environmental test.

Type of test:

Environmental tests usually use single factor test and multi factor combination test to act on products in a certain order. In the reliability test, the comprehensive stress test is used to apply multiple environmental stresses in the same space and at the same time on the sample to simulate the influence of the environmental conditions. In order to improve the accuracy and reliability of the test results, environmental tests have also begun to develop comprehensive tests, and actively develop large-scale multifunctional environmental testing equipment that can simultaneously exert temperature, humidity, vibration, radiation, sand dust, wind and rain stress.

Test time:

In environmental tests, the time of each test depends on the test and the specific test procedure. The difference is due to the different time required for performance testing at each stage. The test time is much shorter than the reliability test. The reliability test time depends on the reliability index that needs to be verified and the statistical test scheme selected and the quality of the product itself. The time can not be determined, so that the total time of the tested product reaches the specified value or can be accepted and rejected.

Main types of environmental testing

1. climate and environmental test

(GB2423, GJB150A, GJB4, IEC60068, GJB1032, GJB322A, GJB360A, GJB548, GB4208, GJB899, TB3021, etc.)

A. temperature test: high temperature test, low temperature test, temperature impact test, temperature change test, fast temperature change test (temperature change rate can reach 15 degrees /min), high temperature aging test, temperature cycle test.

B. humidity (humidity) test: constant humidity heat test, alternating humidity heat test, high temperature and high humidity test (double 85 test, double 95 test).

C. enclosure protection rating test:

IP42, IP44, P54, IP55, IP65, IP66, IP67, IP68 protection level certification and testing services;

D. three protection test: salt spray corrosion test (neutral salt spray test, alternating salt spray test, acid salt spray test), wet heat test (constant humidity heat, alternating humidity and heat), mold test (moldy test, mold test);

E. special test: low pressure test (altitude test), high pressure test, solar radiation test, rain test, sand dust test and so on.

2. mechanical environment test

(GB2423, GJB150A, GJB4, IEC60068, GJB1032, GJB322A, GJB360A, GJB548, TB3058, GJB899, GB/T21563, ISO16750, etc.)

A. vibration test: sine vibration test (sweep endurance test), random vibration test, broadband random vibration test, narrow band random vibration test, sine + random stacking test;

B. impact test: half sine wave mechanical impact test, post peak sawtooth wave impact test and shock response spectrum test;

C. other tests: drop test (free fall, repeated fall), impact test, acceleration test, etc.

3. comprehensive environmental reliability test (GB2423, GJB150A, GJB899, etc.)

A. temperature and humidity combination test, temperature + humidity + vibration comprehensive test (three comprehensive test)

Electronic, electrical, electrical, railway locomotives and military equipment products (environmental test) test standards:

According to the domestic and international standards, we provide optical aging test, temperature and humidity test, gas corrosion test, mechanical vibration test, mechanical impact test, collision test and drop test, dust-proof waterproof test and packing pressure test, and many other environmental and reliability tests. It covers most of the projects of climate environmental test, mechanical environmental test and comprehensive environmental test. It meets the requirements of GJB, GB, GB/T, IEC, ISO, EN, MIL-STD, SAE, ASTM, ISTA, JIS, JIS, ASTM, ISTA, and so on.

Overview of environmental and reliability test standards (excluding GJB)

Climate and environmental testing

Mechanical testing:

Comprehensive testing: