OSGP-LR: A novel method of optimal strain gage placement toward load recovery

Load recovery plays a key role in the safety and performance optimization of mechanical structures, and its accuracy is affected by a variety of factors such as sensor position and direction. Most current sensor optimization methods are based on discrete simulation data, resulting in the optimization quality dependent on the degree of data discretization. This article aims at recovering mechanical structure load using strain response, construct surrogate model to achieve a continuous mapping relationship between the data, and obtain the globally optimal strain gage placement through an optimization method. Firstly, based on the limited simulation data, the comprehensive strain information of the structural surface is obtained by using the spatial strain conversion principle and the local coordinate systems construction method. Secondly, based on the linear superposition relationship between strain response and load, the strain-load coefficient matrix is obtained, and the surrogate model between the strain gage placement and the strain-load coefficient is constructed. Then, the minimization of the variance of the load recovery is taken as the objective function for optimization, and the optimal result is obtained. Finally, both simulation and engineering case studies are carried out. The results verify that the proposed method is capable of accurately recovering the load with an error within 10 –3 %. Moreover, the load recovered at the optimal placement based on the strain response is less susceptible to perturbations. Its corresponding load recovery error is at least 70% lower than that of other placement methods, which indicates a high level of robustness. The proposed method also provides reference and technical support for optimizing strain gage placement on complex surfaces and major equipment.