The Impact Damage Analysis Of3-D Braided Composites

Three-dimensional (3-D) braided composite is a kind of advanced composites. Themechanical properties of3-D braided composites are usually better than ordinarylaminated composites, such as high impact damage tolerance, light weight and highstrength and high energy absorption and so on. Now, the3-D braided composites arewidely used in aerospace, automobile manufacturing, engineering fields of protectionand so on. It is of great importance to study the damage mechanisms and energyabsorption mechanism of the3-D braided composites. To study the impact resistance ofthe carbon fiber/TDE-86epoxy composites, both experimental and numericalsimulation method are used in this paper.Theories about impact dynamics are introduced in the second chapter, includingbasic theories and common failure criteria about composites material, penetration theoryis also introduced in this chapter. The purpose of this chapter is providing a theoreticalbasis for the experimental and simulated rear.The ballistic impact research is developed in the third chapter. The impulseresponse of3-D braided composite and the relationship between residual velocity andincidence velocity are studied. The failure modes of3-D braided composite underdifferent velocity are observed by using the high power microscope, the relationshipbetween incidence velocity and damage area and the effect of incidence velocity on theabsorbing energy of target are studied respectively.The nonlinear finite element method is used to simulate the penetration of targetunder different incidence velocity in the fourth chapter and the simulation results werecompared with experimental results, which proving the effectiveness of this method. Onthis basis, the velocity and acceleration history of the bullet as well as the history ofpenetration resistance are studied. Besides, the history of the displacement of impactposition and vicinity as well as the energy history of bullet and target are studied. At last,the stress history of the target under different velocity is studied.