A Simplified Computational Strategy Focused on Resin Damage to Study Matrix Cracking of The Cross-Ply Laminates Under Uniaxial Tension Load.

Liangliang Sun,Haixiao Hu,Jihui Wang,Aiqing Ni

doi:10.3390/ma12121984

Abstract

Transverse cracking is probably the first and most dominant mode of damage in composite materials. In this paper, transverse cracking of cross-ply [02/90n]s (n = 2,3,4) laminates under uniaxial tension load was studied by means of experimental and numerical methods. In the numerical simulations, a simplified computational strategy only focusing on the damage of the resin was proposed and the mechanical response of the cracking cross-ply laminates was studied by finite element analysis of multi-scale representative volume elements (RVEs). In the RVEs, the longitudinal 0° plies were represented by macro-scale, homogeneous, orthotropic elastic solids while the 90° plies were modeled by the discrete fibers and the surrounding matrix resin in micro-scale. Based on researching the critical longitudinal mechanical strain which initiates the cracks, the in-situ transverse ply strength and the stiffness degradation of the transverse plies, the simplified computational strategy proposed was proven correct. In addition, the crack initiation is sensitive to residual stress. Higher process-induced residual stress levels are dangerous to laminates, leading to early crack initiation.

Highlights

Fiber reinforced polymers (FRP) are extensively used in modern engineering applications which require high mechanical properties and safe reliability
Micro transverse cracks initiate first, combine and propagate until they extend to the ply boundaries, at which point local micro-delamination is triggered
The transverse crack initiation and propagation behavior of cross-ply laminates under uniaxial tension load was studied by means of experimental and numerical methods

Summary

Introduction

Fiber reinforced polymers (FRP) are extensively used in modern engineering applications which require high mechanical properties and safe reliability. Nucleation and propagation of transverse matrix cracking do not normally lead to structural collapse very quickly but degrade the damage resistance and lead to other damage modes like delamination. There is a strong interaction and coupling between transverse matrix cracking and delamination. Micro transverse cracks initiate first, combine and propagate until they extend to the ply boundaries, at which point local micro-delamination is triggered. Delamination becomes the dominant failure mechanism after the transverse crack density has reached saturation up to the catastrophic failure of the composite structure [1]. The onset of transverse matrix cracking is the origin of damage for composite structures. Where and when the transverse matrix cracking initiates and how it propagates are of great interest to the researchers focused on composite damage

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