Micro-mechanical Study Of Particle-reinforced Aluminium Matrix Composites

Due to the very complex fine structure of particle-reinforced aluminium matrix composites,the traditional fine mechanics theory is no longer adequate for solving their mechanical problems.In the numerical analysis,the traditional finite element method needs to divide a large number of small meshes to simulate the fine structure of the particle-reinforced aluminium matrix composites,and it is difficult to assign different material properties to different meshes,which is not well applicable to the particle-reinforced aluminium matrix composites.In this paper,the proposed fine-scale mechanical analysis method is mainly based on the fine-scale structure of particle-reinforced aluminium matrix composites,to explore the influence of changes in the fine-scale structure on the fine-scale mechanical properties of the structure,and to study the three-dimensional static and dynamic analysis of the structure of particle-reinforced aluminium matrix composites based on the fine-scale component distribution of the particle-reinforced phase,the input of gradient functions,and the input of actual fine-scale metallographic pictures of the material.In addition,based on the theory of fine-scale mechanical static and dynamic orthotropic analysis,an inversion and identification technique is developed to invert and identify the unknown parameters of the particle-reinforced aluminium matrix composites.The main research contents and conclusions are as follows:(1)The theory of fine-scale mechanical analysis and inversion theory of particle-reinforced aluminium matrix composites are derived.Firstly,the conventional finite element method is used to divide the components into "macroscopic units",which are further subdivided into "microscopic units",each of which has different material properties and nodal degrees of freedom to achieve coordination and joint action between macroscopic units and microscopic units,and then The computer solution is then carried out.The DFP algorithm is chosen for the single-parameter inversion analysis of particle-reinforced aluminium matrix composites,and the SUMT algorithm is used for the multi-parameter inversion analysis.(2)Based on the basic theory of fine-scale mechanical analysis,the Fortran language is used to develop the static and kinetic programs and the inversion algorithm program,and numerical tests are carried out on the prepared program.The results show that the program prepared in this paper has the advantages of fast calculation and high accuracy.(3)The effects of different particle types,different complex boundary conditions,different gradient functions and different mixed particle types on the macroscopic mechanical properties of the particle-reinforced aluminium matrix composites were investigated,and the results showed that the normal deflection was uniformly distributed along the thickness;the horizontal displacement was linearly distributed along the thickness;the bending stress,the in-plane shear stress and the in-plane shear stress were linearly distributed along the thickness,In-plane shear stress is distributed along the thickness higher curve;normal shear stress is distributed along the thickness parabolic;extrusion stress is distributed along the thickness tertiary curve,these results are consistent with the theory of homogeneous thin plate.(4)Based on fine structure picture of the random distribution of the particle-reinforced phase and the input of the metallographic picture of the particle-reinforced aluminium matrix composite based on the real high entropy alloy,the static analysis of the structure of the particle-reinforced aluminium matrix composite was carried out,and the fine mechanical volume change curve and the stress contour map reflecting the fine structure change inside the material were obtained,which can well reflect the fine structure distribution of each material on the metallographic picture.The fine structure distribution of the material,the small changes in the fine structure of the material can be fully reflected,further proving the accuracy of the fine mechanical analysis method described in this paper.(5)The kinetic analysis of the particle-reinforced aluminium matrix composites was carried out using the fine-scale mechanical dynamic analysis program to obtain the three-dimensional distribution of the intrinsic frequency values,displacement vibration patterns and stress vibration patterns.The results show that: different component distributions have a great influence on the dynamic characteristics of the composite plate,with a maximum difference of 10%;the maximum difference in the intrinsic frequency of the composite plate with different material particles is 15%;the maximum difference in the intrinsic frequency of the plate with different volume fractions of high entropy alloy particles is 10%.(6)The inversion analysis program developed was used to invert and identify unknown parameters within the particle-reinforced aluminium matrix composites.In other words,based on the deflection and inherent frequency values obtained from the static and kinetic test measurements,the inversion and identification analyses were carried out for the particle-reinforced phase gradient function distribution index,the external load,the modulus of elasticity of the single or mixed particle-reinforced phase,Poisson’s ratio,mass density and material name.The inversion and identification techniques proposed in this paper are highly accurate and suitable for this type of non-homogeneous material with complex fine structure.