For this part we will going to talk about the test equipment
The test equipment should meet the requirements for “test equipment” for high temperature, low temperature, and vibration (sinusoidal) test methods. The high temperature test chamber should be able to maintain the specified temperature and deviation within the test working space, and forced air circulation can be used to maintain temperature uniformity. In order to limit the influence of radiation, the difference between the temperature of each part of the inner wall of the test chamber and the ambient temperature specified in the test (calculated in Kelvin temperature) should not be less than 3%. The test sample should not be subject to direct thermal radiation from heating and cooling elements that do not meet the above requirements. . The absolute humidity should not exceed 20g/m³ of water vapor (equivalent to 50% relative humidity at 35°C). When the test temperature is lower than 35°C, the relative humidity should not exceed 50%, and the low-temperature test chamber is in the working space. It should be able to provide the specified temperature conditions, and forced air circulation can be used to maintain temperature uniformity; in order to limit the influence of radiation, the difference between the temperature of each part of the inner wall of the test chamber and the specified test temperature should not exceed 8% (calculated according to Kelvin temperature) and Test specimens shall not be exposed to direct radiation from any heating or cooling elements that do not comply with the above requirements.
The structure of a commonly used vibration table installed in a temperature box is shown in Figures 1 and 2.
(1) Commonly used comprehensive temperature and vibration testing equipment, the vibration table extends into the temperature test chamber. Its structural form is shown in Figure 1:
Figure 1 Comprehensive platform with the vibration table extending into the temperature chamber
1-Test sample; 2-Temperature monitoring box; 3-Temperature box wall; 4-Partition plate; 5-Vibration table; 6-Vibration monitoring point
(2) The structure of the vibration table installed in the temperature box is shown in Figure 2:
Figure 2 The structure of the vibration table installed in the temperature box
1-Test sample; 2-Temperature monitoring box; 3-Test sample; 4-Vibration table; 5-Temperature box
Install the vibration table in the temperature test chamber. For this test, heat conduction between the vibration table and the test chamber must be avoided, because this heat conduction will degrade the performance of the vibration table and the temperature test chamber. For this reason, there should be good thermal insulation between the test sample and the vibration table. A common method is to add a layer of suitable thermal insulation material (or equivalent pad) between the test sample and the vibration table. However, it should be noted that the selected insulation material cannot reduce the necessary rigidity of the installation. In some cases, especially when testing at higher frequencies, it is more appropriate to use ceramic materials as insulating materials. It must also be noted that any devices used to thermally insulate the shaker from the test chamber (such as partitions) should generally not transmit excessive vibrations, and there must be no mechanical coupling between the shaker and the test chamber as it may produce excitations that may damage the test Box structure.
The vibration table used for comprehensive testing can be a mechanical vibration table, an electric vibration table or an electro-hydraulic vibration table. Since the electro-hydraulic vibration table has a large structure and the pressure oil is sensitive to temperature, mechanical vibration tables and electro-hydraulic vibration tables are currently commonly used at home and abroad. Electric vibrating table, among which electric vibrating table is the most commonly used.