Modelling cyclic material behaviour using finite element method

The structural integrity assessment and design of mechanical components under cyclic loadings can be approached by using Finite Elements numerical simulations. The numerical model generally requires the definition of geometry, loads and a suitable material constitutive model, depending on the analysis type. Until now, many types of constitutive models have been developed to describe the monotonic and cyclic elasto‐plastic behaviour of materials. For example, pure isotropic hardening is appropriate to model the monotonic material response, while kinematic hardening is used to model the Bauschinger's effect under unloading. Mixed isotropic and kinematic models, instead, could be used to capture the hardening and softening behaviour in cyclic material response (Chaboche, 1986). Some models are also implemented in Finite Elements commercial codes and are usually adopted in industrial applications, while other more complex models may require very high computational times that could be unfeasible for industrial needs. In addition, the model complexity often demands an additional experimental effort to estimate materials parameters to fit and validate the constitutive model. This research activity aims to provide a survey and comparison on various material models that are suitable to numerically simulate the monotonic and cyclic elasto‐plastic behaviour of materials, with special emphasis on copper alloys. A Finite Element analysis of a simple structure under strain‐controlled loading is used to compare different material models. A sensitivity analysis has also been performed to understand the role of different parameters in each model. The obtained results allow a better understanding of which model is more suitable to capture the monotonic and cyclic elasto‐plastic material behaviour.
PhD ExpO Year: 
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Ingegneria Meccanica e Meccatronica