Control of parameters of the calculation model of a spatial structure based on the results of full-scale tests

Introduction. In numerical modelling of mechanical systems, the proximity of the computational model to the actual behaviour of the object is largely determined by the adequacy of the specified boundary conditions. In practice, the support conditions of structural elements often differ from the idealized assumptions adopted in computational models, which leads to discrepancies between calculated and experimental data.

Materials and methods. This study considers an approach to optimizing the boundary conditions of a finite element model using the evolutionary algorithm CMA-ES [1]. The object of investigation was a spatial frame structure, for which experimental studies of dynamic characteristics — natural frequencies and free vibrations — were conducted. The comparison of calculated and experimental frequencies and vibration modes was performed using the modal assurance criterion (MAC) and the relative error between the calculated eigenfrequencies of the model and their experimentally determined values. Based on these metrics, the objective function of the optimization problem was formulated.

Results. The optimization made it possible to determine the stiffness coefficients of the support connections in the lower chord of the structure in six degrees of freedom. The results showed that the application of the evolutionary approach significantly reduced discrepancies between model and experimental data, thereby improving the accuracy of the computational model.

Conclusions. The accuracy of finite element modelling of structures can be improved by aligning the model and experimental dynamic characteristics through the use of evolutionary algorithms.

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