基于强度变化特征的汽车结构件轻量化设计方法

Weight-reduction Design of Auto Structures Based on Strength Features

提出一种获得结构有限寿命的轻量化设计方法。该方法以结构强度变化特性为基础,以结构强度试验结果为依据,动态强度方程为指导,结构临界载荷为目标,提高设计应力为核心,借助有限元分析实现汽车结构件减重设计。应用此方法对某国产载货车前桥进行减重设计,通过设计该前桥的危险断面,减小前桥的横断面尺寸,降低该前桥的临界载荷,使试验应力提高到能对前桥结构造成强化锻炼的区域。台架疲劳试验表明,虽然每台减轻质量5.5kg,减重后的前桥仍能达到相关标准要求。这种方法比目前广为采用的以有限元分析和许用应力为基础的无限寿命轻量化设计方法更能充分发挥材料的强度潜力,因而可以在更深层次上实现结构的轻量化。基于强度变化特征的汽车结构轻量化对目前世界上日益强调的汽车轻量化具有重要的学术价值和指导意义。对基于强度变化特征的汽车结构件轻量化设计方法进一步改进和完善后,在其他工程领域也将具有重要的应用和参考价值。

A weight-reduction design method is presented, which can make auto components and parts with finite life. The method is technically based on the strengthening and degenerating properties of the structure strength meanwhile combining dynamic strength equation （i.e., calculating model） with strength test results of auto parts. In order to realize the given critical load or the design goal, finite element method is used in getting a rational increase of design stress. As an application of this method, a truck front axle was re-designed. By designing the critical section and reducing the figuration dimensions, a lower critical load of the front axle is obtained. Consequently the test stress is increased to an area of causing the strength of axle not to be strengthened under repeated stresses. As a result, the mass of front axle was reduced with 5.5 kg. The new axles were verified to fulfill the strength standards on test rig, and no obvious change was observed for static strengths aider fatigue tests. The tests results show that the strength potential of components and parts of automobile could be exerted more fully than that designed with the method of using finite element analysis adding to the allowed stress, which can only make the design of infinite life for auto parts. The light weight design for components and parts of automobiles can be realized in a deeper extent with this new method. This new method is of important science value and guidance meaning for now a day＇s development in auto light weighting, engineering value in many industrial fields other than in auto industry.