Experimental and numerical studies on the damage behaviour of open hole CFRP composite specimen subjected to compression

K, Varaprasad and Raju, Gangadharan (2018) Experimental and numerical studies on the damage behaviour of open hole CFRP composite specimen subjected to compression. Masters thesis, Indian Institute of Technology Hyderabad.

Text
Thesis_Mtech_ME_4265.pdf - Submitted Version
Restricted to Repository staff only until August 2019.
Download (10MB) | Request a copy

Abstract

In this work, the progressive failure of open hole composite specimen subjected to compression is studied. CFRP composite laminates of various stacking sequence (Unidirectional, Cross-ply, quasiisotropic) with a circular hole are fabricated and tested under compressive load conditions. An anti-buckling compression fixture is used to avoid buckling. In this work, an unified experimental approach comprising of digital image correlation (DIC), Acoustic emission (AE) and strain gage are used to study the damage mechanisms of CFRP specimen under compression. DIC is employed to capture the strain field near the hole on the surface of the CFRP specimen. AE is used to study the initiation and progression of various damages in CFRP specimen. AE parameters are then used to classify the various damage events in uni-directional, cross-ply and quasi-isotropic laminates. Strain gages are also employed to capture the failure strain information near the hole. Subsequently, fractography studies are carried out under an optical microscope to study the interaction of various damage mechanisms. Finite element simulation of the progressive damage failure of the open hole CFRP specimen is done using ABAQUS software. Three dimensional brick elements (C3D8R) are used to simulate the compression failure. A VUMAT subroutine is coded to study the matrix compression and fibre kink failure based on Pinho’s damage model. Numerical results obtained from FE simulations are then compared with experimental observations, and the accuracy of the FE model is validated.

[error in script]

IITH Creators: