Closed Chain Simulations of a Cast Aluminium Component - Incorporating Casting Process Simulation and Local Material Characterization into Stress-strain Simulations

Abstract

The coupling between simulations of solidification, microstructure and local mechanical behaviour and simulation of stress-strain behaviour is studied by applying a recently developed simulation strategy to a high pressure die cast aluminium component. In the simulation strategy, named a closed chain of simulations for cast components, the mechanical behaviour throughout the component is determined locally by a casting process simulation. The entire casting process, including mould filling and solidification, is simulated to predict the formation of microstructure and residual stresses throughout the component, and material characterization models are applied to relate microstructural features to local elastic and plastic mechanical material behaviour. The local material behaviour is incorporated into a finite element method (FEM) stress-strain simulation of a realistic load case of the component in service.In the current contribution the influences of local variations in mechanical behaviour and residual stresses on the component behaviour are investigated. The simulation results for local microstructure and mechanical behaviour are compared to experimental results, and the predicted local mechanical behaviour is incorporated on an element level into the FEM simulation. The numerical effect of the variations in mechanical behaviour is quantified by comparing the results achieved using local behaviour and homogeneous behaviour. The influence of residual stresses predicted by the casting process simulation on the component behaviour is also studied.The casting process simulation is found to accurately predict the local variations in microstructure throughout the component, and the local variations in mechanical behaviour are well described. The numerical results show that casting process simulation and modelling of microstructure formation, material behaviour and residual stresses are important contributions to correctly predict the behaviour of a cast aluminium component in service. This motivates the use of the proposed simulation strategy, and show the importance of incorporating materials science and casting process simulations into structural analyses of cast components. It is discussed that integration of these areas, e.g. using the closed chain of simulations, is important in order to increase the accuracy of FEM simulations and the product development efficiency in the future.

Integrated fatigue life predictions of aluminium castings using simulated local microstructure and defects

“…Different simulation-based approaches have been presented that aim to consider the impact of defects on the mechanical performance of aluminium casting [8][9][10][11][12]. In this work, the closed chain of IOP Publishing doi:10.1088/1757-899X/1281/1/012067 2 simulations for cast components previously presented by the author and coworkers [11,12] forms the basis.…”

“…Different simulation-based approaches have been presented that aim to consider the impact of defects on the mechanical performance of aluminium casting [8][9][10][11][12]. In this work, the closed chain of IOP Publishing doi:10.1088/1757-899X/1281/1/012067 2 simulations for cast components previously presented by the author and coworkers [11,12] forms the basis. Here casting process simulation with microstructure modelling is used, and material characterisation models are applied to predict local microstructure-based mechanical behaviour [12].…”

“…In this work, the closed chain of IOP Publishing doi:10.1088/1757-899X/1281/1/012067 2 simulations for cast components previously presented by the author and coworkers [11,12] forms the basis. Here casting process simulation with microstructure modelling is used, and material characterisation models are applied to predict local microstructure-based mechanical behaviour [12]. The results are incorporated as local material data into Finite Element Method (FEM) simulations of the casting in use.…”

“…The approach was initially developed to handle local static elasto-plastic material behaviour based on local variations in microstructure [11] These local variations were shown to have an important effect on the stress-strain distribution in ductile iron castings [13]. This effect is also observed in aluminium samples [14], but in HPDC castings the effect of residual stresses and defects were found to have a larger impact on the performance of the casting [12]. The local porosity levels predicted by the casting process simulation were then applied to a local quality factor, reducing the achievable elongation to failure.…”

Effect of Material Inhomogeneity on Thermal Performance of a Rheocast Aluminum Heatsink for Electronics Cooling

“…Often such a cooperation is restricted in the product design phase due to the lack of established methods capable of considering the effect of manufacturing method on the final properties of components. For instance, in aluminum casting, local variations in the mechanical behavior of a finished component due to the variation of microstructural characteristics can cause deviations from that predicted by finite element simulations based on a homogeneous material description [3].This is often not addressed in robust design of cast components.…”