Finite Element Method Simulation Study Of Strain Gage Thermal Output Under Transient Heat Load

Electric resistance strain gauge is one of the most widely used method in engineering test.The temperature is an important factor in impacting the test precision of electric resistancestrain gauge. This article described the thermal output、temperature compensation method andthe technical measurement problem which are produced from the strain gauge under theabnormal temperature; Aiming at the influence of temperature on the strain gauge testingsystem, the simulation study on thermal output of strain gauge has taken use of finite elementmethod.In-deepth analysis of the influence factors of the material properties on the thermaloutput of the object being measured. The effect of temperature on the accuracy of the testsystem are related to the material properties of the material being tested, Young’s modulusand thermal expansion coefficient of the strain gauge and the temperature coefficient ofresistance are the main factors affecting the thermal output of the strain gauge measurementsystem.Taking use of the steady-state thermal module and static structure module of Ansys-Workbench to solve the strain measurement error of WK-05-125BK-10C strain gauge, which isproduced by the coefficient of linear expansion,combining with the effects of Karma alloywhich is under different temperature to resistance-temperature coefficient to export thermaloutput of the strain gauge; comparing finite element calculation results with foreign data,finding the absolute error of the measurement system is agree with the simulation resultswhich is under steady and abnormal temperature. It proves that the finite elementanalysis is workable for the simulation on the thermal output of the strain gauge. In thecondition of transient abnormal temperature, the simulation research in the transient thermalmodule and transient structure module needs to be done by setting different temperature risingrate and boundary conditions which is under different measurement environment. Thesimulation results are close to the experiment data in the condition of steady state andabnormal temperature. When the temperature rising rate is between5oF/sec and40oF/sec, the transient thermal output of the strain gauge is steady, when the temperature rising ratereach or exceed80oF/sec, the transient thermal output of the strain gauge is acute. Researchshows：the calculation results using Ansys are coincident with experimental results preferably.Applying simulation technique to temperature test system of strain gauge has an extensiveprospect. The research results provide a theoretical basis for improvement, optimization anddesign of strain gauge test system.