Simulation of the Calibration Process of the Strain Gauge Measurement Systems

The article presents a method for simulating the calibration of a load force measurement system, based on strain gauge sensors mounted on a mechanical structure, in order to determine relationships for calculating load forces using the indications of the strain gauge sensors. The research whose results we make known aimed to estimate the extent to which the knowledge of the stress or strain on the border of a metallic structure that works in the linear-elastic regime, is possible and, if so, with what precision. Accuracy refers to the difference between the forces estimated using empirical relations using the indications of the deformation sensors and the known values of the loading forces of the structure. This definition of accuracy has a direct counterpart in the physical calibration operation. Using the obtained results, a plausible definition of the calibration operation of the load measurement system of a structure, based on strain gauge sensors, is formulated. The explanation of the simulation method and its benefits is made by analyzing a simple case, with an analytical solution and also, on the case of a structural model of agricultural equipment. Are presented two types of linear relationships that link loads of the structure to the indications of strain gauge sensors, and also, their prediction errors, which are estimated in relation to the “experimental” values (results from numerical analysis). The benefits of the simulation are exposed, among which the optimization of the positioning of the strain gauge sensors and of their number, in order to decrease the prediction errors and to increase the amount of information obtained by calibration.