Shape memory alloy thermal circulation stability and function fatigue property testing system

Abstract

The invention discloses a shape memory alloy thermal circulation stability and function fatigue property testing system which comprises a temperature control box, a sample bracket, a thermal circulation temperature control system and a data acquisition system, wherein the temperature control box is of a hexahedron hollow structure; a flexible polyimide heating film of the thermal circulation control system is adhered to the bottom of a stripped shape memory alloy sample; an anode/cathode lead of the flexible polyimide heating film is connected with a heating end of a time relay; the time relay is connected with a direct-current voltage-stabilizing power supply; a thermocouple signal conditioning module and a laser tube displacement sensor of the data acquisition system are connected with a data acquisition card; the data acquisition card is connected with a computer; one end of a K-type thermocouple is connected with a thermocouple signal conditioning module; and the other end of the K-type thermocouple is connected with the flexible polyimide heating film. By adopting the shape memory alloy thermal circulation stability and function fatigue property testing system, shape and temperature variation of a shape memory alloy in the thermal circulation process can be displayed and stored in real time through data acquisition and processing, and the function fatigue property of the shape memory alloy in the thermal circulation process can be relatively well evaluated through analysis.

Description

technical field [0001] The invention relates to the testing of shape memory alloys, in particular to the functional characteristics and microstructure evolution testing of metal intelligent materials under long-term thermal cycle loads, and is a method for quantitatively evaluating the working stability and function of shape memory alloys during long-term thermal cycle service. A test system for fatigue behavior and microstructural evolution. Background technique [0002] Shape memory alloys have unique functional properties such as shape memory effect and superelastic deformation, as well as excellent mechanical properties, so they are widely used in the fields of smart structures, micro drives, damping and shock absorption, and biomedicine. Usually, by performing a certain "training" treatment on the shape memory alloy, it can obtain different deformation capabilities under thermal actuation, such as elongation, shortening, bending, etc., to meet different applications. I...

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Problems solved by technology

[0003] China's invention patent applications for "A Thermomechanical Fatigue Experimental Device for Shape Memory Alloys" (publication number CN105181734A) and "Multifunctional Tester for Shape Memory Alloy Wire" (publication number CN 101122559A) mainly use joules through current loading The heat heats the sample. In order to meet the faster heating rate of the larger sample, a larger voltage must be used, which has a greater safety hazard; The local temperature is too high, the heating is uneven, and the current is introduced during the experiment, so the influence of the current on the sample in the long-term fatigue test cannot be ruled out

The above existing technologies can only monitor the deformation of the shape memory alloy in the uniaxial direction, but cannot monitor the bending deformation; and because the extensometer is used to measure the deformation of the sample during the thermal cycle, the installation of the extensometer requires a certain space. Therefore, it is impossible to measure samples with a smaller size; in addition, the above published patents all use natural air cooling, which cannot achieve a faster heating-cooling cycle action

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