Numerical Simulation Of Gradual Damage On Bolt-bonded Hole Composite Laminates

Due to its excellent mechanical properties,composite materials are not only widely used in aerospace and other high-tech fields,but also applied well in many other fields.In practice,due to production conditions or other conditions,the actual needs of several components will be connected to meet the use of functions.Therefore,the connection of composite materials is an inevitable problem;mechanical connection technology,cementing technology and hybrid connection technology came into being.Mechanical connections have the advantage of being simple to maintain at a later stage,so mechanical connections are more common in composite connections.In addition,due to the engineering needs,for example,for wiring,alignment;maintenance,repair and other issues,the practical application of composite laminates,there will be drilling problem.Therefore,the mechanical connection of composite laminates punch research has great significance.The related research contents of this article are as follows:Firstly,introduction of anisotropic elastomer theory,laid the theoretical basis for follow-up composite materials;Abaqus finite element simulation software introduced,and detailed description the needed content,provided basis for model create.Secondly,introduced several failure criteria and material stiffness degradation model,compared the USDFLD,UMAT,VUMAT three user subroutines,and selected Hashin and Alvaro failure criteria write the VUMAT user subroutine.Thirdly,using the user subroutine written in this paper,a numerical experiment was carried out on the tensile test of a single screwed mechanical connection.Compared the ultimate load and the final failure mode obtained by the simulation with the literature to verify the feasibility of the model.Finally,According to "Design Handbook of Composite Materials",a feasible double nailed mechanical connection structure of carbon fiber / polyimide composite was designed,and the diameter of different openings of double-nailed mechanical connection laminates was simulated.Then,two typical failure mode structures were selected for a detailed analysis of progressive damage.