An experimental and numerical investigation of progressive damage analysis in bonded patch repaired CFRP laminates

Abstract

The damage evolution in composite material is a complex phenomenon, comprising several interacting failure modes like matrix cracking, fiber breakage, debonding and delamination. Damage initiation, its propagation and ultimate strength prediction of composite structure is of paramount importance for developing reliable and a safer design and utilizing them as primary load bearing one. During service life, these structures get damaged and are often repaired for extending their service life. In the present work, a 3D finite element-based progressive damage model is developed for predicting the failure and post-failure behaviour of notched and repaired panel under tensile load. Failure initiation load, ultimate strength and failure mechanisms are investigated through the developed progressive damage model. The accuracy of developed finite element model is assessed by comparing its prediction with the experimental results obtained from digital image correlation technique and they are found to be in good agreement. In this study, the panels made of carbon/epoxy composite laminates of pure unidirectional and quasi-isotropic stacking sequence are considered. The damaged panel is repaired with both single- and double-sided circular patch of same parent material. Stress-based 3D-Hashin’s failure criterion is used for predicting the damage mechanism. Maximum shear stress and strain criteria are considered to account for patch debonding. It is found that the damage in notched panel always initiates with matrix cracking around the hole. However, damage in repaired panel is influenced by localized patch debonding.

Strain Field of Reinforced Concrete under Accelerated Corrosion by Digital Image Correlation Technique

“…A reasonable way to decrease even eliminates the error caused by off-plane displacement and correction factor 'k' has been investigated by researchers (Dai et al 2013;Wang et al 2012). And previous studies using DIC and strain gage measurements by the authors have shown the errors in DIC strain measurements are less than 50 micro strains (Kashfuddoja et al 2015). The experiment results from Hamrat et al (2016) and Wang et al (2012) suggest that the classical measurement techniques (strain gauges, LVDT sensors) and the DIC technique are suitable for the analysis of strain components.…”

Assessment of local strain field in adhesive layer of an unsymmetrically repaired CFRP panel using digital image correlation

“…Around the circular hole there are 15360 elements (96 circumferential; 40 radial; 4 thickness). The meshing surrounding the hole is chosen based on mesh convergence study [34,35]. Every layer is meshed with one element in thickness direction for both patch and panel.…”

Progressive damage analysis of adhesively bonded patch repaired carbon fibre–reinforced polymer specimen under compression involving cohesive zone model

“…Bhise et al (2014) have optimised the circular composite patch reinforcement applied over CFC laminate involving both mechanics-based and genetic algorithm in conjunction with 3D finite element analysis (FEA). Kashfuddoja and Ramji (2015) conducted an experimental and numerical investigation of progressive damage analysis of an external bonded patch repaired CFC laminates under tensile loading. Both single-and double-sided patch configuration were considered.…”

“…The damage initiation, progression and mechanisms for the tensile and compressive loading are significantly different for the external patch repaired CFC laminates. In the earlier work (Kashfuddoja and Ramji, 2015;Ubaid et al, 2014), authors have focused on tensile loading of external patch repaired CFC laminates and multiple hole CFRP laminate respectively. The present work focuses on the behaviour of externally patch repaired CFC laminates under pure compression loading.…”