Simulated environmental testing is an activity carried out to use, transport or store products in an intended environment to maintain product functional reliability. The simulated environmental test is mainly used to analyze the degree of influence of environmental factors and its mechanism of action.
Because the simulated environmental test is not subject to nature, it is not limited by time and place, saving manpower, material resources, and can be carried out all day. Therefore, simulated environmental tests are widely used around the world. On the one hand, it shows its scientific nature, on the other hand, it also confirmed its value. Simulated environmental testing techniques are the result of long-term repeated practice by several generations of scientists.
Simulated Environmental Test Classification
Under normal circumstances, environmental tests are divided into two categories:
- Climate environment test
- Mechanical environment test
1. Climate environmental tests mainly include high temperature, low temperature, low pressure (divided into normal temperature and low temperature and low pressure gas), damp heat, alternating humidity, high and low temperature themal shock, high and low temperature cycling, salt spray, mold, sand and so on.
2. Mechanical environmental tests mainly include vibration, shock, collision, centrifugation, transportation, fall and collapse, and so on.
Many companies lack understanding of the simulated environment test, lack of relevant basic knowledge, and lack of experience. Blindly invested in some high-priced equipment, but did not play its due role. In addition, some staff members do not understand the test standards and test methods. Even some staff members use equipment without fully understanding the operation of the equipment, which has unimaginable consequences.
1. Repeatability: For the same test sample under the same environmental conditions, the same person uses the same test method and repeats the test several times with the same precision measuring instrument. The measurement results are consistent.
2. Reproducibility: The same test sample is under different environmental conditions. Different people use the same test method and test with the same precision measuring instrument, and the measurement results are consistent.
3. Syntony and resonance have the same meaning. For example, resonance means that when the frequency of the vibrating table is the same as the natural frequency of the sample to be tested. The generated vibration is called resonance even if it syntony. But there are differences in some occasions. Taking syntony as an example, it refers to the frequency inherent in an object. Each product has its own inherent frequency, and syntonye refers to an independent object. Resonance refers to two objects.
Misunderstandings Occur in Environmental Testing
1. Is the idea of ”the worse the environment is better” during the test? What are the consequences of this?
Experimenting with this idea often results in an overload test of the product. For example, if the temperature test is 120 °C ± 2 °C, the operator may intentionally set it to 122 °C ± 2 °C. Some people think that the product is not too strict, so the temperature is intentionally set to 118 °C ± 2 °C. Both of these practices do not understand the rigor of the standard. They did not realize that this practice would artificially cause deviations of up to 4 °C away from the specified value.
2. The location where the tested product is placed
The product to be tested should be placed in the effective part of the environmental chamber. It should be placed on a stainless steel frame in the environmental chamber or suspended. In short, try to ensure that the test specimens in the environmental chamber are subjected to the same stress. Instead of stacking like a pile of firewood.
Do not place the test article on a lacquered object to avoid the introduction of artificial additional contamination. Imagine if you put an electroplated piece on such an object for high temperature or high temperature or mold test. Can this lead to accurate test results?
Selection of Environmental Test Standards
The two types of environmental tests can be carried out either individually or in combination (but not random). In addition to the comprehensive test contents mentioned above, the most common tests such as temperature humidity vibration combined test are used. There are applicable test requirements and methods for these test contents. Commonly used standards in China are GB2423, GJB150A, GJB4, GJB1032 and so on. International standards are: MIL-STD-810D, IEC60068, ISO16750 and so on.
Only test conclusions made in accordance with relevant standards are credible and will be recognized by the appropriate country or organization. Testers must not change the standards themselves or blindly.
Differences in test methods directly affect the consistency of test results. The technical contract not only stipulates the acceptance criteria for delivery, but also has specific requirements for the use of equipment, test methods, procedures, and the like. Even some small differences can lead to two conclusions. Therefore, it must be carefully considered and strictly observed.
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