Abstract
Research and/or Engineering Questions/Objective
Carbon fiber composite showed great potential of lightweight in automotive body panel, even structural components, such as B-pillar. In addition, lightweight structures design with novel composite offers numerous advantages over conventional design. The objective of this study was to propose the lightweight structure designs of B-pillar with carbon fiber composite, then by design validity investigation and parameters optimization in FE software according to specific impact safety regulations and lightweight performance, the optimal lightweight structure of B-pillar would be obtained.
Methodology
A new idea of structure optimization with carbon fiber was applied in this study, which only replaced part of the component materials and changed other component parameters, such as thickness, to balance the performance of safety and lightweight. Based on the material properties of T700, which were gained by experiments, two design projects of B-pillar was proposed. Towards every project, according to "Automotive Side Impact Occupant Protection" (GB20071-2006), the simulation of side impact in FE software was conducted to obtain the relatively optimal project by comparing the condition of stress and deformation of B-pillar. On this basis, regarded the invasion amount and intrusion velocity of the four characteristic positions which were head, chest, abdomen and pelvis as evaluation index, regarded the force conditions of B-pillar which were obtained by the side impact simulation as the input conditions, a multi-index orthogonal design was conducted. Finally, an optimal design structure was obtained by weighing crashworthiness, occupant protection performance and equivalent performance of the conventional B-pillar.
Results
In this paper, an optimal structure design project of B-pillar with carbon fiber composite was obtained, which included the details of material assignment and component parameters. The optimal project, which replaced the material of reinforced panel by carbon fiber and reduced the thickness of other components, has better safety and lightweight performance compared to conventional B-pillar. Furthermore, the main finding from the orthogonal design was that, when carbon fiber was used on B-pillar, different components of B-pillar accounted for different weights of safety performance, thereinto, outer panel (upper) weighs most, followed by outer panel (lower) and reinforced panel .
Limitations of this study
An important limitation of the current study was that the optimal design project was not the most optimal project due to the mathematics method (orthogonal design) used in the research. Furthermore, it would be much better if the dummy injury values were used as the evaluation index and took some other safety test conditions as optimization conditions.
What does the paper offer that is new in the field including in comparison to other work by the authors?
The structure design of B-pillar with carbon fiber composite, which realized lightweight by replacing some component materials with carbon fiber composite and changing the rest components’ parameters, met the safety impact regulations. The whole idea was new and cost saving compared to the research which just replaced all the components material with carbon fiber.
Conclusions
An optimal sturcture design project of B-pillar with carbon fibre composite was obtained. The process proves that it is completely feasible and effitive when a new idea of structure design was used on B-pillar.
Key Words : Lightweight structure; B-pillar; Carbon fiber composite; Orthogonal design