Acoustic Emission-Based Methodology to Evaluate Delamination Crack Growth Under Quasi-static and Fatigue Loading Conditions

Milad Saeedifar,Kaivan Mohammadi,Reza Mohammadi,Mohamad Fotouhi,Hossein Hosseini Toudeshky,Mehdi Ahmadi Najafabadi

doi:10.1007/s10921-017-0454-0

Abstract

The aim of this study was to investigate the applicability of acoustic emission (AE) technique to evaluate delamination crack in glass/epoxy composite laminates under quasi-static and fatigue loading. To this aim, double cantilever beam specimens were subjected to mode I quasi-static and fatigue loading conditions and the generated AE signals were recorded during the tests. By analyzing the mechanical and AE results, an analytical correlation between the AE energy with the released strain energy and the crack growth was established. It was found that there is a 3rd degree polynomial correlation between the crack growth and the cumulative AE energy. Using this correlation the delamination crack growth was predicted under both the static and fatigue loading conditions. The predicted crack growth values was were in a good agreement with the visually recorded data during the tests. The results indicated that the proposed AE-based method has good applicability to evaluate the delamination crack growth under quasi-static and fatigue loading conditions, especially when the crack is embedded within the structure and could not be seen visually.

Highlights

Fiber reinforced plastic composites (FRP) have many advantages such as high specific strength, specific stiffness, etc. [1,2,3,4]
Saeedifar et al [35] determined interlaminar fracture toughness of glass/ epoxy composites under mode I, II and mixed-mode I&II loading using acoustic emission (AE) and finite element (FE) methods
The aim of this paper is to investigate the delamination propagation in glass/epoxy composites under mode I quasistatic and fatigue loading conditions

Summary

Introduction

Fiber reinforced plastic composites (FRP) have many advantages such as high specific strength, specific stiffness, etc. [1,2,3,4]. The principal mode of failure in laminated composites is the separation along the interfaces of the layers, viz, delamination [9,10,11,12,13,14]. This failure results in dramatic reduction of residual strength and stiffness of the structure. Mode I delamination is the most common mode of failure occurred in the structures. This is due to lower energy that is required for the initiation of mode I delamination [15,16,17]

Objectives

Methods

Results

Conclusion