Investigation of Governing Equations and Computational Modeling of Crack Initiation and Growth in Kevlar Fiber Composites Using Python-Based Numerical Methods

This study presents a comprehensive numerical investigation of crack initiation and growth in Kevlar fiber-reinforced composites using a Python-based computational framework. The mechanical behavior of this orthotropic composite under plane strain conditions was modeled, and crack initiation was predicted using the Hashin failure criterion. Crack growth after initiation was simulated using the energy-based Cohesive Zone Model (CZM), enabling the gradual and nonlinear observation of crack length evolution and stress distribution. The effects of key parameters, including fiber orientation, laminate thickness, and hybridization with carbon fibers, on critical strain, crack growth rate, and energy release were systematically analyzed. Results showed that crack initiation occurs at a strain of approximately ۰.۲۱%, and crack length increases nonlinearly with increasing strain. The stress field around the crack tip exhibited classical singular behavior (σ ~ ۱/√r), confirming the physical validity of the model. The proposed framework allows accurate prediction of failure behavior in Kevlar composites and has significant applications in the optimization of design and failure assessment of fiber-reinforced structures in engineering and defense industries.

Keywords:

Kevlar composite , crack initiation , crack growth , Hashin failure criterion , Cohesive Zone Model (CZM) , Python-based numerical simulation , energy release