Mesoscopic Finite Element Simulation And Impact Damage Analysis Of Spread Fiber Tow Woven Composites

Compared with traditional unidirectional tape composites,woven fiber reinforced composites are widely used in the aviation and automotive industries because of their unique undulating structure,no clear growth path for macrocracks in the resin matrix,and better structural stability.Adopting the fiber bundle spreading process can make the fiber tow thinner,on the one hand,it can reduce the degree of buckling of the yarn in the material,improve the mechanical properties of the composite material,and on the other hand,it can increase the design of the thickness direction of the composite laminate structure.Compared with the extensive research on the failure theory of traditional woven fabric composites,the failure mechanism and crack propagation mechanism of thin-layer composites after spread fiber tows under impact loads are unclear.To this end,this paper proposes to construct a meso-analysis model of angleply spread tow woven composites under impact load,and then studies the progressive damage characteristics of composites from the perspective of multi-scale analysis.First,a plain weave composite laminate with a fiber bundle spreading pavement form of [(0/90)/((-45/45)/(0/90))4/(0/90)]s was designed,and the meso-scale finite element model of the spread tow woven composite was established using the geometry of the woven structure.The characteristics of fiber bundle undulations were described using the hyperelliptic curve equation.In addition,considering that the overall RVE model of woven composites in the presence of mixed plies does not have a periodic geometry,three different size representative volume units were generated to determine the unit cell model of the optimal size.Then,a continuous damage model including fiber bundles,pure matrix and interface layer was established to simulate the progressive damage behavior of each component.Secondly,a quasi-static tensile and compression experiment was performed on the angle-ply spread tow woven composite material,and the global mechanical response and fracture characteristics of the woven composite material were analyzed through the experimental results.Combined with the experimental results,the size sensitivity analysis of the RVE model was performed on the finite element prediction results of three different size cells,and the optimal size RVE model was determined.In addition,by determining the local damage behavior and local stress field distribution of the RVE model,the progressive damage behavior of the stretched woven composite was investigated.The results show that the matrix damage under tensile load has almost no effect on the global stress and strain.The tensile failure mode is fiber bundle fracture,while the compression failure mode is mainly caused by fiber bundle fracture,matrix cracking and delamination damage.Finally,in order to investigate the impact response of the spread tow woven composite,a meso-scale homogenization model that reflects the fluctuate characteristics of the interlaced areas of the fiber bundle was established.The unit cell size of the homogenization model was consistent with the verified meso-model,and the quasi-determination of the meso-scale homogenization model was verified by comparing the global mechanical response,local damage characteristics and strain fields of the meso-model.By comparing the experimental data in the literature,the established multi-scale analysis model can effectively reflect the fiber bundle fracture and matrix crack growth under the impact load of the material.