Engineering challenges in Alloy wheel rim for safety simulations

Aluminium alloy wheels are widely used in the automotive industry over the last decade due to its superior styling and performance. Alloy wheel rim is one of the critical components and plays an important role in a frontal crash scenario. Alloy wheel rim failure prediction in safety simulation is essential to ensure robust safety performance. Determining failure characteristics of an alloy wheel poses many difficulties considering its brittle nature, porosity and inhomogeneity in material properties across different regions of wheel rim due to mould design, cooling rate and other process parameters of the low-pressure die casting process. This paper describes the modelling and simulation methodology developed to predict accurate wheel behaviour. The methodology addresses two distinct areas of challenges such as alloy wheel rim failure prediction and associated tire blow out. Alloy wheel rim material was characterised considering the inhomogeneity of material properties at different regions such as the rim, spokes and hub. The material model developed, considering strain rate sensitivity, anisotropy due to the state of loading, ductile normal and shear fracture aspects. Scatter function developed to simulate material property variation. Radial tire characterisation carried out with detailed modelling of constituents such as rubber, steel beads, body plies and steel belts. Various physical tests and CAE correlation studies carried out at coupon and tire assembly level to represent the stiffness and deformation of the tire accurately. A novel approach was developed using CAE sensors to detect the alloy wheel rim failure in real-time. This triggers rapid air leakage in the tyre to simulate the blowout scenario during the crash event. The methodology has validated at the subsystem and full vehicle level by carrying out multiple physical tests. This approach can be used for digital development and validation of alloy wheel rim design to ensure robust crash safety performance.