Crystal plasticity and continuum anisotropic plasticity module:
One key problem which has plagued the widespread use of light alloys in automotive industries is their poor formability compared to steels. The topic of formability is complicated in the sense that a plethora of microstructural features such as precipitates (coherent and incoherent), solutes (static and dynamic), precipitate free zones, dispersoids, constituent particles, grain size distribution and texture coexist together in Al alloys and each of them plays an significant role in controlling the formability during the metal forming process. Considering the industrial importance of this topic, an additional challenge is to have a quick and real time estimate of formability to save time and expenses. However, to comprehend the effect of above-mentioned microstructural features on plastic properties and consequently on formability, crystal plasticity models are required, which are computationally expensive.
We at the Experimental and Computational Materials Mechanics lab would like to provide the bridge between the computationally expensive crystal plasticity models and the relatively fast continuum anisotropic yield criterions. We plan to perform systematic mechanical testing followed by crystal plasticity modelling to calibrate the parameters of the continuum anisotropic yield criterions. Subsequently, we plan to integrate the yield criterions with necking and fracture theories such as Marciniak-Kuczynski model and Modified Cockcroft criterion to predict the forming limit curve. Furthermore, we also plan to investigate the effect of other parameters such as stress triaxiality and Lode parameter on fracture behaviour.
Projects:
- The role of strain path and stress state on plasticity and damage evolution: A crystal plasticity based investigation.
- Yield surface evolution and prediction of forming limit curve for age hardenable Al alloys with novel microstructures.
Other deliverables:
- Development of a user-friendly pipeline based on MTEX and elasto-plastic self-consistent simulations (EPSC) for estimating the effect of texture and hardening behaviour on the shape of the yield locus and the formability parameters.
- Development of various open source yield criterions ranging from Hill’s, Hosford’s and Barlat’s family to the upper bound Taylor-Bishop-Hill criteria.