Finite Element Analysis And Lightweight Design Of The Passenger Car BIW

Automotive energy economy, safety and environment protection are threesubjects of automotive development in the future. As well as reducing weight,improving handling and dynamics performance, achieving the target of energyconservation and environment protection, auto lightweight technology is toguarantee the crashworthiness, body stiffness and other properties. So autolightweight technology has become a key project in automobile industries withbroad prospect for development. This paper carries out finite element analyses onthe body-in-white (BIW) of a passenger car for stiffness, vibration, strength and thefrontal and side crashworthiness. In the mean time, structure improvement andlightweight design respectively for stiffness, vibration and crashworthiness areconducted.Simplified models are obtained by simplifying typical components of BIW. Bythe study on static performance and dynamic characteristics of BIW simplifiedbeams and sheets of different materials, the relationships between different materialsof beams and sheets for some properties are found and the reference for materialsubstitution of BIW components is provided.The simulation model of BIW under static performance and vibrationcharacteristics is established. BIW bending stiffness, torsional stiffness, modalfrequency and corresponding strength are analyzed. The performance sensitivityanalyses are conducted to select components for further optimization. Materialsubstitution and size optimization are carried out for selected components in order torealize BIW lightweight design based on static performance and vibrationcharacteristics.The finite element model of side impact is created. The side crashworthiness ofthe original scheme and lightweight scheme are analyzed. On the basis of thelightweight scheme，the side structure is improved. Carry out lightweight design onside frame panel, B pillar and threshold beam by the method of TWB, reducingweight and improving side crashworthiness.The simulation model of frontal impact is created and analyzed. On this basis,the structure of the front is improved and the front side rail is designed with TWB,promoting frontal crashworthiness.