The Optimal Design Of Composite Engine Hood Layup Based On Frontal Impact

With the increasingly serious problems of environmental pollution and energy crisis,automobile lightweight technology,as an important means of energy saving and emission reduction,has attracted more and more attention from automobile manufacturers and research institutions.CFRP is an ideal material for automobile lightweight because of its excellent properties such as light weight,high specific strength,corrosion resistance and fatigue resistance.In this paper,carbon fiber composite material is applied to the engine hood to study the optimal design of its stacking sequence under the condition of frontal high speed collision.The main research content and conclusions of this paper are as follows:(1)Simplify the CAD model of the original steel engine hood.Select the fiber and matrix materials and design the initial layup according to the performance requirements of the engine hood.Build the finite element model of composite engine hood and mesh it in HyperMesh software.Four kinds of working conditions were selected to compare the basic mechanical properties and masses of the steel engine hood and the composite engine hood.(2)According to GB11551-2014,a collision system was established,and the finite element simulation of front collision of engine hood was carried out in LS-DYNA.Compared with the original steel hood and composite hood,the results show that the energy absorption of composite hood with initial layup is less than that of the original steel hood,but within acceptable range.(3)Take the Angle of each layer of the inner and outer plate of the engine hood as the design variable,take the energy absorption as the evaluation index.Conduct the test design through the Latin hypercube method,obtain 80 groups of sample data and establish the Kriging approximate model on this basis.The optimal model was established by selecting the layup Angle as the design variable,the energy absorption as the optimization objective and the maximum deformation as the constraint.The results show that the crashworthiness of the engine hood is further improved compared with the initial layup.