DETERMINATION OF PROPERTIES OF GRATED MATERIALS BASED ON KALMAN FILTER ALGORITHM

To determine the elastic-plastic constitutive parameters of functionally graded material (FGM), an improved inverse analysis procedure based on the Extended Kalman Filter (EKF) technique was proposed. In this procedure, the load-indentation depth curves from indentation test were utilized in combination with finite element simulation to determine the material parameters. A gradual homogenization treatment of data both from test and finite element simulations was conducted to improve the accuracy of solution by reducing the effects of random errors from system and measurement. At the same time, the load-indentation depth response surfaces were constructed by Lagrange interpolation function based on the numerical simulation results in order to promptly obtain the resultant response from any set of material parameters in the prescribed domains, thereby greatly enhancing the efficiency of inverse analysis; Besides, two load-indentation depth curves obtained from different sizes of indenters were used as input data to carry out the inverse analysis, in order to further improve the convergence, accuracy and well-posedness of solutions. This paper addresses the identification of FGM material parameters in details from different aspects and accordingly provides a valuable reference for research on inverse problems.