Study On Structural Strength Of Glass Fiber Reinforced Injection Molding Components

With the rapid development of rail transportation industry,glass fiber reinforced composite materials have been broadly used,and injection molding technology is one of the most economic,efficient and widely used molding means.In order to predict and analyze the load-bearing characteristics and structural strength of glass fiber reinforced injection molding components accurately,it is necessary to consider the anisotropy of the material produced by the glass fiber orientation distribution.Based on the mechanical theory of composite materials,considering glass fiber mass ratio,the interaction between glass fibers,glass fiber aspect ratio and injection molding process parameters on the influence of mechanical properties of glass fiber reinforced injection molding components,glass fiber homogenized RVE model was established,and the orthotropic macroscopic mechanical properties of glass fiber reinforced composite and structural strength of injection molding components were studied.The main work is as follows:Firstly,by studying a continuous function between the second-order tensor of glass fiber orientation and glass fiber orientation angle,glass fiber homogenized RVE model was established for injection molded glass fiber reinforced composites.Based on Taguchi orthogonal test design method,the glass fiber reinforced composites RVE model of simulation was carried out with DIGIMAT software for quantitative analysis of glass fiber mass ratio(A),glass fiber aspect ratio(B)and glass fiber orientation tensor(C)on the influence of mechanical properties of glass fiber reinforced composites.Secondly,considering glass fiber layered effect on injection molded glass fiber reinforced composites in the injection molding process,sandwich model is proposed and the lay-up design was carried out.Based on grey box theory and reverse engineering,and selecting glass fiber length-diameter ratio,surface/thickness ratio and core/thickness ratio,surface of glass fiber orientation tensor and glass fiber orientation vector rotation angle as four influence factors,the inversion to predict the orthotropic elastic constants of glass fiber reinforced composite PA66(GF50)were carried out,and in contrast with material tensile testing macroscopic elastic modulus E33,Poisson's ratio u31 and Poisson's ratio u32,the relative error of 0.92%,1.82% and 2.43%,respectively.Thirdly,the fiber orientation of the glass fiber reinforced composite material components was studied during the injection molding process,and based on the generalized Newtonian fluid constitutive equation,using ARD-RSC glass-fiber orientation model,numerical simulation was used to predict fiber orientation distribution of the glass fiber reinforced injection molding components by considering the interaction between glass fibers.Based on the composite material micromechanics mean field homogenization method,using composite meso-scale modeling,discrete RVE model field,injection molding and structural finite element analysis techniques,the structural anisotropy strength analytical method of glass fiber reinforced injection molding components was proposed.Lastly,strength analysis of the traction rod injection molded part shows that the simulated dangerous position is in good agreement with the actual damage location.On the basis,the structure of traction rod is improved,the results show that the maximum principal stress of the rod reduced by 57.18% under the tensile load and 71.25% under the compressive load,which show that the through-hole design of glass fiber reinforced injection molding engineering components is not conducive to improve its structural strength on the load-bearing.