Numerical and Theoretical Analysis for Investigation of Impact Strength for the Rear Bumper of a Passenger Car

Design is the preliminary stage of product development and analysis. In the past bumpers were simply a large beam of metal attached to the front and rear of the vehicle. While functional, the weight of such a bumper can contribute significantly to the overall weight of the car. Higher vehicle weights equal lower fuel efficiency. Bumpers now must fulfill not only their primary function, but must do so while being aesthetically pleasing, and without contributing significantly to the weight of the vehicle, thereby improving fuel economy standards. The bumper system has changed over the last three decades due to new government safety regulations and styling concepts. The ability to maintain the vehicle intact at high-speed impact conditions and to damp the kinetic energy are the most important factors in bumper system selection besides its weight, manufacturability, cost, reparability, and formability of materials. These changes in material however, may result in a comprised ability of the bumper to perform its primary function. This research work is aimed to investigate the low impact failure analysis for the rear bumper. The problem is investigated using theoretical analysis as well as numerical methodology with Finite Element Analysis. The research is presented with variants of two different bumper materials proposed for the impact strength investigation of the rear bumper to be used in the automotive industry. In FEA, the competent software ‘HyperMesh’ is used for determining the impact stress induced in different materials of the rear bumper of the passenger car. The failure strength of the bumper depends on many factors such as material properties, geometries, shape, size, ribs provided, absorbing material, etc. Among them, impact strength can be regarded as the most dominating factor affecting the failure strength of the bumper.