Abstract
Research and/or Engineering Questions/Objective
Compared with the conventional type of automobile body, frame autobody has good performance in light weighting, material used, costing and machining technology. In order to improve the performance of the frame autobody, a load path testing and analysis were used. And then based on the result of load path, the optimization of the layout of the beams were conducted, and some improved designs were approved.
Methodology
In this study, a load-path experiment was conducted on a frame auto-body which was fixed at torsion test bench subjected to a certain torsion moment. The internal force and moment of each key beam were identified by analyzing the strain of the beams measured from the test. According to the internal forces of the frame, the certain load path of the frame subjected to torsion moment could be plotted. Meanwhile, the finite element analysis of the frame auto body was also developed and this method was validated by the above mentioned experiment. Based on the internal force and load path, some internal force optimization suggestions were proposed aiming to reduce the internal force. Finally, the influence of the layout and section of the key beam on the load path were carried out based on the testing frame body.
Results
By comparing the internal force and moment before and after layout optimization, it could be noticed that the layout of the beam members played an essential role in the load path, and the optimized layout was an effective way to lead the load path more efficiently and reduce the high internal force.
Limitations of this study
After the optimization of frame members layout, the results were not validated by test.
What does the paper offer that is new in the field incomparison to other works of the author?
The proposals to improve the performanceof frame auto body mainly focused on the optimization of the section modulus. However, optimization of the section modulus is not the most efficient method for the frame automobile body. Load path of the frame is also an important consideration of the automobile body design.The load path analysis is an effective method to describe the reason of the high stress from the point of force.
Conclusions
In this paper,the load path test was conducted to find out the stress and internal force composition of each member. Based on the load path analysis, four proposals were approved to decrease the internal force level. And then the finite element method was used to validate the improved design. Finally, the effect factor of load path was studied. It is concluded that the layout of the beam members could lead the load path effectives, and the stiffness distribution could influence the distribution of load.
Key Words : frame Autobody; load path testing and analysis;layout optimization