Dynamic plastic impact behavior of CNTs/fiber/polymer multiscale laminated composite doubly curved shells

Abstract

In the present paper, the dynamic elastoplastic response of carbon nanotube (CNT) fiber/polymer multiscale laminated composite (CNTFPC) doubly curved shell subjected to low-velocity impact of the projectile is investigated. For this purpose, the effective material properties of the multiphase composite are calculated by combining the Halpin-Tsai model and a micromechanical approach that strengths are estimated by an empirical equation and modified through a mixture rule. The elastoplastic constitutive equations are obtained incrementally using Hoffman’s criterion and isotropic hardening model. Also, the Green-Lagrange type of nonlinear kinematics is extracted in terms of displacement terms based on Reddy’s higher-order shear deformation theory for the CNTFPC shell. All incremental relations are regulated in the framework of the updated Lagrangian formulations to solve by an iterative finite element procedure through conforming isoparametric quadrilateral elements. Moreover, an elastoplastic Brake’s contact model is developed to determine truly the contact force between the CNTFPC plate and impactor. Temporal discretization is done by the Newmark’s average acceleration scheme. The results are validated with the data available in the literature to demonstrate the accuracy of the model. A parametric study was carried out to analysis stress and investigate the yield conditions and the effects of plastic deformation, weight percentage of CNTs, fiber volume fraction and curvature radius on the contact force history, indentation, permanent indentation depth, central deflection. Numerical results show that in the low velocity impact analysis, the stresses occurring in the shell for the areas further away from the contact area are also yielded.