A Simple Algorithm for the Extraction of Plasticity Parameters from Indentation Data via Finite Element ModellingTuesday (27.09.2016) 16:30 - 16:45 Part of:
The hardness and stiffness of materials are measured in a rather routine way from indentation tests. There has, however (and there continues to be), a strong interest in the development of indentation methods for characterising more complex (and potentially more useful) material behaviour. Plasticity is one example, where the objective is to use indentation load-displacement curves to infer (somehow) a value for the yield stress and the parameters that describe the work-hardening behaviour of metallic materials. Analytical methods have proven to be inadequate since they simply cannot account for complex hardening behaviour and the evolution of complex stress and strain fields. Numerical methods (finite element modelling) have been much more successful, although no universally accepted methodology has yet emerged that is transparent, tractable and easy to implement and use. In this presentation a simple methodology/algorithm for converging on plasticity parameters from indentation data using inverse finite element methods is presented. The robustness of the methodology is demonstrated using real experimental data and guidelines for ensuring the uniqueness of solutions are discussed. A stand-alone software tool called SEMPID, which utilises the proposed algorithm and which incorporates built-in finite element capabilities, will be demonstrated. The software tool has been designed for the indentation community and requires no prior experience of finite element analysis. Its simplicity and ease of use are expected to offer very broad appeal and its extension to cover the extraction of creep and coating material properties will be covered in the talk.