The Research On The Influencing Factors And Thermal-Mechanical Decoupling Of Resistance Strain Gauge Measurement

In the resistance strain gauge measurement, the constituent elements of its structurewill affect the measurement properties in certain extent, and its work environment willlargely affect the output of strain gauge and measurement results. Therefore, acantilever beam model is looked as the research object, establishing cantilever beamstructure and thermal-mechanical coupling finite element model consist of cantilever(measured body), binder and strain resistance wire. Based on the model, the work andits corresponding conclusions of this paper are as follows:â‘ First, cantilever beam model is validated, and model validation is divided intotwo parts:1) the establishment and validation of pure cantilever beam model;2) theestablishment and validation of overall cantilever with strain gauge. Evaluating thevalidation of overall cantilever beam model through the error of resistance wire outputstrain and true strain of cantilever beam. The results showed that: the error of resistancewire output strain and the true measured strain of cantilever beam maintained at about5.5%, indicating that the stability of strain gauge measurement and its smaller error,proving the validity of the cantilever beam model.â‘¡Then, a simple analysis of the static and dynamic characteristics of theestablished resistance strain gauge is made to prove that the built strain gauge has goodstatic and dynamic characteristics. Studying the influencing of sensitive gate length,gate wire spacing and gate wire diameter on the strain gauge measurement error,obtaining the influencing and disciplin of every parameters on strain gaugemeasurement error, gaining the optimal parameters of strain gauge measurements.â‘¢Based on thermal and thermal-mechanical coupling theory, Selecting countcases to validate effectiveness of the LS-Dyna thermal-mechanical coupling calculationmethod through comparing the theoretical values and simulation values. The resultsshowed that: thermal conductivity temperature distribution and results of simulationagree with theoretical; the error of thermal strain, thermal stress and theoretical issmaller. Proving the validity of the LS-Dyna thermal-mechanical coupling modelcalculation method.â‘£Finally, the thermal-mechanical coupling and decoupling of cantilever beammodel was calculated and analyzed. Analyzing the influencing of binder and resistancewire on strain gauge measurement results because of temperature. Therefore, achieving thermal-mechanical decoupling of strain gauge output results through analyzingthermal-mechanical coupling strain of cantilever beam and revising measurement stressof strain gauge, gaining true stress and strain of cantilever beam measured position.