A comprehensive study on failure of the adhesively bonded CFRP joints using cohesive zone modeling

Karthik, Dongri and M, Ramji (2019) A comprehensive study on failure of the adhesively bonded CFRP joints using cohesive zone modeling. Masters thesis, Indian institute of technology Hyderabad.

Text
Mtech_Thesis_TD1558_2019.pdf
Restricted to Repository staff only until 5 August 2021.
Download (24MB) | Request a copy

Abstract

Simulating fracture initiation and propagation using cohesive zone model (CZM) has gained popularity in fracture mechanics domain around the world because of its ability to predict both crack initiation and propagation, ease of implementation and its ability to simulate physical interfacial cracks such as delamination in composites. The accuracy of the CZM in predicting loaddisplacement response depends on the traction – separation law used. In this work, performance of bilinear, trilinear and trapezoidal cohesive laws in simulating the delamination failure in Carbon fiber reinforced polymer (CFRP) composites and debonding in adhesively bonded CFRP composites is studied. Pure Mode-I and Mode-II delamination behaviour with R-curve effects are modeled using these cohesive laws and later their performance is compared. Finite element analysis (FEA) simulations are done using Abaqus® software. VUMAT subroutines are written for implementing the trapezoidal and trilinear cohesive laws whereas Abaqus inbuilt cohesive model is used for implementing the bilinear law. It is observed that bilinear traction – separation law is unable to accurately predict the delamination in DCB and ENF models where R – curve effects are predominant. However, both the trapezoidal and trilinear cohesive laws are able to predict the experimental behaviour and hence are preferred for modeling the delamination failure in CFRP composites. In simulating the debonding failure of adhesively bonded CFRP laminates with longer overlap area trapezoidal law gives accurate results over bilinear whereas in the case of shorter overlaps bilinear law gives accurate results.

[error in script]

IITH Creators: