Guanlong Chen

Use of high strength steel sheet for lightweight and crashworthy car body

Abstract Car body lightweighting and crashworthiness are two important objectives of car body design and improvement. In order to reduce a cars weight without impairment of crashworthiness, a method of body parts’ material replacement from mild steel sheet to high strength steel sheet of reduced depth is brought forward. The depth reducing equation is drawn from mechanical analysis and verified by finite element simulation of body parts crashing into a rigid wall. The depth of several main parts for impact energy absorption is reduced according to the equation brought forward in this paper and the simulation results of the car crash into a rigid wall show that the method presented in this paper is valid.

Study on Structural Lightweight Design of Automotive Front Side Rail Based on Response Surface Method

Nowadays, vehicle lightweight design is a main topic in automotive industry. Crashworthiness, which is the most important performance of a full vehicle, must be always satisfied in the study on body lightweight design. This paper presents research, from the point of view of safety, of structural lightweight design of the front side rail of a passenger car. The response surface method is used to create mathematical models that represent the relationship between structural sheet thicknesses and absorbed energy of the entire structure in the frontal crash simulation, and the relationship between structural sheet thicknesses and the mass of the entire structure. Then an optimization process is performed, and the structural mass and original absorbed energy are defined as objective and constraint functions, respectively. Minimum mass and structural sheet thicknesses are obtained with the satisfaction of original absorbed energy of the front side rail structure. The weight reduction of the front side rail is 26.95%.

Automated Hierarchical Assembly System Construction in Automobile Body Assembly Planning

DFA (design for assembly) is an approach to designing products with ease of assembly in mind. Multilayer assembly system construction and possible assembly sequencing are important information for DFA, especially at the prototype design stage of an automobile. This paper aims to help automobile designers construct a hierarchical assembly system, develop a systematic approach to automated subassembly detection, and assembly sequencing in automobile body assembly planning. Modeling of an automobile assembly is given, based on precedence knowledge among automobile parts. Algorithms to detect possible subassemblies with two-step verification and to generate all available sequences are also developed in this study.

The stiffness and buckling behavior of panels with stamping-induced imperfections

With the decrease of sheet thickness, the stiffness and buckling behavior of automobile body panel are more and more concerned. In this paper, the stiffness and buckling behavior of panels with stamping-induced imperfection is studied. Imperfections caused in drawing and springback are obtained by finite element analysis and introduced to define the initial state of the panel before indenting. The indenting procedure is simulated in ABAQUS Standard. In order to solve the buckling problem, a viscous pressure that is proportional to the relative velocity between surfaces is added artificially. For comparison, a simplified model in which imperfections are not considered is also established. Comparing the simulation results with the reference experiment, we find that the stamping-induced imperfections lead to a more severe oil canning phenomena under a buckling load, although they increase panel’s initial stiffness a bit. Moreover, among all stamping-induced imperfections, the geometrical imperfection (surface deflection) is beneficial to increase panel’s buckling load, and the material imperfections (residual stress and uneven thickness) help to decrease panel’s buckling load and can make oil canning more severe during post-buckling. Influences of blank holder force, sheet thickness and material property on panel stiffness and buckling behavior are also studied. The work of this paper is beneficial to processing optimization, material selection, and reinforcement design for automotive exterior panels.