IMPLEMENTATION OF CIRCULAR DISCONTINUITIES IN CFRP BUMPER BEAM FOR MATERIAL SAVING: A CASE STUDY

An automotive bumper system consists of an energy absorber, fascia and bumper beam. Among them, the bumper beam is the main component contributing to the overall weight of the vehicle. The bumper beam absorbs the kinetic energy during an accidental collision by deflection in low speed impact and by deformation in high speed impact. Carbon Fibre Reinforced Plastic (CFRP), being an extremely strong and lightweight composite, is a good candidate for bumper beam material. Earlier used in high performance cars CFRP is nowadays being promoted to be used in passenger cars also. The reinforcement beam is the vital part which ensures safety and needs to be validated through Finite Element Analysis (FEA). Therefore, the double hat bumper beam is impacted with a cylindrical impactor and analyzed in Abaqus. In this paper the bumper beam is analyzed after weight reduction by putting circular holes for material saving. Further the effect on cost of production is calculated. Above all, material saving reduces carbon footprint.

Modelling of Reversed Austenite Formation and its Effect on Performance of Stainless Steel Components

The kinetics of reversed austenite formation in 301 stainless steel and its effect on the deformation of an automobile front bumper beam are studied by using modelling approaches at different length scales. The diffusion-controlled reversed austenite formation is studied by using the JMAK model, based on the experimental data. The model can be used to predict the volume fraction of reversed austenite in a temperature range of 650 - 750 C. A 3D elastoplastic phase-field model is used to study the diffusionless shear-type reversed austenite formation in 301 steel at 760 C. The phase-field simulations show that reversion initiates at martensite lath boundaries and proceeds inwards of laths due to the high driving force at such high temperature. The effect of reversed austenite (RA) on the deformation of a bumper beam subjected to front and side impacts is studied by using finite element (FE) analysis. The FE simulations show that the presence of reversed austenite increased the critical speed at which the beam yielded and failed. RA fraction also affects the performance of the bumper beam.