Characterization of Material Parameters by Reverse Finite Element Modelling Based on Dual Indenters Vickers and Spherical Indentation

摘要

Significantly advantage in the use of indentation testing its use for the characterization of materials is simple and requires only a small sample. In material characterization by indentation, the material behaviour is represented by the load (P)- depth (h) in the P-h curve. However, despite the breadth of use of indentation in the evaluation of the behaviour of the material has not been able to explicitly relate the behaviour of materials with constitutive material properties. This encourages further research to be able to predict the P-h curves and hardness and indentation resistance of the constitutive parameters of the material, it is also very important for research and practical use to explore the potential for using indentation data for predicting the constitutive properties of a material. This could potentially provide a faster way for identification of material parameters and applied in situations where a standard specimen is not available. In this research, the relationship between the constitutive parameters of the material (represented by the yield stress (σy) and work hardening coefficient (n)) of elasto-plastic materials, Indentation P-h curve, and Hardness value with dual indenters have been systematically investigated by combining the representative stress (σr) analysis and FE modelling using steel as a system materials. FE model of Vickers and Spherical indentation has been developed and validated. Validation conducted on the feasibility of the FE models to investigate approaches to the material system, and establishing factors affecting the accuracy and robustness of the approach finite element programs used. A new approach for predicting the hardness values are developed based on the 3D relationship between hardness, yield stress (σy) and strain hardening coefficient (n). The prediction proposed method has been successfully used to produce hardness values of various material properties and is used to establish the relationship between the hardness values with representative stress. Prediction process of the material parameters based on the intersection between the indentations curves of the material properties of both the dual indenter Vickers and spherical indentation. It provides a useful tool to evaluate the feasibility of using a hardness value in predicting the constitutive material parameters with respect to the accuracy and uniqueness by mapping through all the range of potential materials.