Research And Design Of Crashworthiness Of Composite Corrugated Sandwich Panels

Compared with the traditional composite structure,the composite sandwich structure consists of two thin composite panels and a thick core material in the middle.It has the characteristics of light weight,high specific stiffness and high specifi c strength.Excellent crashworthiness and energy absorption characteristics make it widely used in automotive,aerospace engineering fields.When subjected to external load,the composite sandwich structure absorbs energy through the complex deformation and failure of panels and core materials,and the core configuration is the key to affect the crashworthiness and energy absorption of the sandwich structure.Reasonable core configuration can fully dissipate energy through a specific deformation mode and enhance the crashworthiness of the structure.In the context of the increasing requirements for structural performance in the engineering field,it is of great significance for the further engineering application of composite sandwich structure to design the core with specific crashworthiness and study its deformation and damage mechanism.Composite corrugated sandwich plate is studied in this paper.Based on the theory of continuum damage mechanics,a numerical damage model,which includes the initial failure criteria and stiffness reductio n of composite panels,metal cores and interfaces,is established to accurately simulate the quasi-static collapse response.The main work of this paper is as follows:Firstly,three letter types of corrugated cores are designed to study the influence of core configuration on the crashworthiness of corrugated sandwich composite plates,including “X”,“Y” and “A” types.The deformation and energy absorption mechanism of corrugated sandwich plate under crushing were analyzed,and the effect of core thickness on energy absorption was studied.The results show that compared with the traditional trapezoidal corrugated cores,the crashworthiness and energy absorption capacity of the sandwich plates can be improved by using three letter types of corrugated cores.The corrugated sandwich panel with A-shaped core has the highest energy absorption efficiency.The total energy absorption and specific energy absorption of the three kinds of corrugated sandwich panels increase with the increase of core thickness.Then,based on the concept of gradient induced trigger,two new stiffened corrugated cores with gradient vertical stiffeners embedded in the trapezoidal corrugated cores are proposed,including descending gradient configuration and ascending gradient configuration.The response of stiffened corrugated sandwich plate under plane crushing is analyzed,and the effect of the gradient level and the number of stiffeners is studied.The results show that the failure mode of corrugated core is improved by the reinforcement configurati on with descending gradient.The peak load is reduced,and the energy absorption efficiency is improved.In addition,increasing the gradient level not only improves the energy absorption capacity of the sandwich plate,but also makes the load more stable.The energy absorption of sandwich plate can be improved by increasing the number of stiffeners.Finally,a new type of stiffened sandwich with horizontal stiffeners embedded in the vertical stiffened corrugated core for coupling reinforcement is proposed.The crashworthiness and energy absorption characteristics of the sandwich plate are studied,and the typical parameters such as the thickness and position of the horizontal reinforcement are discussed.The mechanism of coupling reinforcement is analyzed through the internal energy and deformation mode of the structure.The results show that the embedding of horizontal stiffeners can effecti vely improve the bearing stability and energy absorption of the sandwich plate.In addition,the thickness of the horizontal stiffeners has little effect on the crashworthiness of the sandwich plates.The highest energy absorption efficiency is achieved when the reinforcement position is located at the middle height of the core.