Study On Prediction Method Of Tensile And Compressive Strength Of Civil Aircraft Fiber Metal Laminate Stiffened Panel Under Unidirectional Load

As a new type of lightweight structural element,fiber reinforced metal wallboard has drawn wide attention in many fields such as aerospace and aviation.In practical applications,the siding structure is subject to external loads,and fatigue damage and buckling instability are the most common forms of failure.In order to ensure the safe use of large structural members of civil aircraft reinforced metal fiber reinforced siding,engineering designers often need to test the failure characteristics of the test and strength check,but the test method is susceptible to negative factors such as the surrounding environment and high costs,repeatability is poor,long cycle.In order to avoid time-consuming and costly repeated tests and to promote better application of fiber reinforced metal panels,the strength of the panel under axial tensile load and axial compressive load was studied by theoretical method and finite element method,establish a reasonable and feasible siding strength prediction method system.In the theoretical analysis,the theoretical analysis of the tensile strength of composite laminates and Al-Li alloy welded panels was conducted.According to the blending law of elastic modulus in composite mechanics,the tensile strength of large-scale fiber reinforced metal panels was established.The theoretical prediction formula and the verification of the theoretical formula have certain accuracy.At the same time,through the improvement of the traditional ultimate load method,the theoretical prediction formula for the axial compressive failure strength of the fiber reinforced metal panels is deduced,and the ultimate bearing load and compressive strength of the panel are obtained.The estimated value and the comparison with the compression test result show that the theoretical prediction value is 2.92% smaller than the experimental value.The ABAQUS finite element software was used to simulate and analyze the axial compression of the fiber reinforced metal panels.The buckling damage load and the overall failure load were obtained.The comparison shows that the fiber reinforced metal panel still has a large bearing capacity after local buckling.A large post-buckling load-bearing space,through the failure of the output cloud diagram observed that the axial compression damage of the wall plate structure is mainly the partial buckling of the long inter-deep skin,the local long-winding buckling and the overall wall plate instability damage.At the same time,the wallboard structure was simulated by loading simulation.The simulation results were compared with the experimental values,the relative deviation was small,and the output stress cloud diagram could observe the high stress area of the wallboard,showing its failure process,and the new structure in the future.In the pre-research phase,the finite element simulation can be used to replace the tensile test of large-scale structural parts of aircraft wall panels,reducing the pre-research period and cost,and improving the efficiency of the test.In addition,this paper discusses in detail the effect of the height,thickness and number of the stringers on the ultimate failure strength of fiber-reinforced stiffened panels.After comprehensively considering the material utilization rate and economic cost,according to the analysis of the trend of the curve,the optimal design scheme of siding long-siding structure is provided.