Cuong Ha-Minh

Effect of Frictions on the Ballistic Performance of a 3D Warp Interlock Fabric: Numerical Analysis

Abstract3D interlock woven fabrics are promising materials to replace the 2D structures in the field of ballistic protection. The structural complexity of this material caused many difficulties in numerical modeling. This paper presents a new tool that permits to generate a geometry model of any woven fabric, then, mesh this model in shell or solid elements, and apply the mechanical properties of yarns to them. The tool shows many advantages over existing software. It is very handy in use with an organization of the functions in menu and using a graphic interface. It can describe correctly the geometry of all textile woven fabrics. With this tool, the orientation of the local axes of finite elements following the yarn direction facilitates defining the yarn mechanical properties in a numerical model. This tool can be largely applied because it is compatible with popular finite element codes such as Abaqus, Ansys, Radioss etc. Thanks to this tool, a finite element model was carried out to describe a ballistic impact on a 3D warp interlock Kevlar KM2® fabric. This work focuses on studying the effect of friction onto the ballistic impact behavior of this textile interlock structure. Results showed that the friction among yarns affects considerably on the impact behavior of this fabric. The effect of the friction between projectile and yarn is less important. The friction plays an important role in keeping the fabric structural stability during the impact event. This phenomenon explained why the projectile is easier to penetrate this 3D warp interlock fabric in the no-friction case. This result also indicates that the ballistic performance of the interlock woven fabrics can be improved by using fibers with great friction coefficients.

Numerical study on the effects of yarn mechanical transverse properties on the ballistic impact behaviour of textile fabric

A numerical model of ballistic impact on a two-dimensional Kevlar KM2® plain-woven fabric has been validated by experiment. This paper shows that it is necessary to experimentally measure material constants of yarns for having good input parameters of the model. Effects of yarn Poisson’s ratio, transverse and shear modulus on impact behaviors of a simple crimped yarn and a complete fabric have been carried out. The effect of the Poisson’s ratio can be negligible in both impact cases: on a single crimped yarn and a complete fabric. The same conclusion has been proven for the effect of the transversal modulus except the cases of its so low values that can cause yarn early damage. The shear modulus of a yarn appears to be an important material parameter that mainly influences the ballistic performance of a two-dimensional plain-woven fabric. When using a very high value of a shear modulus of yarn, a crimped single yarn is broken immediately after contact with projectile in pure shearing mode.