Analysis Of The Influence Of Composite Reinforcing Pad On The Dynamic Characteristics And Ant-concave Of The Door Outer Panel

The door is one of the important assemblies of the automobile outer cover.At the beginning of the automobile shape design,it needs to consider the dynamic characteristics and ant-concave for the door outer panel.However,due to various factors,the dynamic and ant-concave of the door under the state of test piece can not meet the design specifications sometimes.In order to save cost,the auto manufacturer considers to use reinforcing pad to improve the anti-concave performance of the door outer panel and dynamic characteristics to make up for the design deficiencies.In this thesis,the dynamic characteristics and anti-concave performance of the original door and the reinforced door are compared and analyzed.The reinforcing pad is required to be developed by an auto manufacturer.The material parameters of the reinforcing pad were measured by the related instruments.Using the computer simulation technology,the finite element model is established by Hypermesh.The modal analysis of the original door and the reinforced door is carried out by using the Optistruct solver,and the modal parameters of the original door and the reinforced door are obtained.The modal frequencies are compared and analyzed,the influence of the door reinforcing pad on the dynamic characteristics of the door is evaluated.The results show that the second,fourth and ninth modal frequencies of the door outer panel are increased by 0.1%,0.4% and 0.3%,respectively.It show that the dynamic characteristics are affected to a certain extent by using the reinforcing pad,but the effect is not obvious.Using the signal processing technology,the modal tests of the original door and the reinforced door are carried out by using the relevant equipment.Through the comparative analysis of modal parameters,it is verified that the numerical model of the calculated modal and the entity of door have a high consistency.By processing the experimental modal parameters,it is found that the second,fourth and ninth modal frequencies are increased by 1.2%,0.6% and 0.7%,respectively.The results show that the reinforcing pad can affact the dynamic characteristics of the door outer panel to a certain extent in experimental state,but the effect is not ideal.It is not recommended to use the reinforcing pad as a scheme to improve the dynamic characteristics of the door outer panel.Based on the theory of buckling analysis,using ABAQUS solver,using three evaluation indexes of door anti-concave performance: plastic strain,residual variable and maximum displacement,the anti-concave performance of the original door and the reinforced door are compared and analyzed.It is found that the maximum displacement of the door outer panel is reduced by 44.92%,and there is no plastic strain under 400 N vertical load.The conclusion that the reinforcing pad has a significant effect on improving the anti-concave performance of the door outer panel is obtained.