Title: Prediction of critical thrust force for exit-ply delamination during drilling composite laminates: thermo-mechanical analysis

Authors: Jamel Saoudi; Redouane Zitoune; Suhasini Gururaja; Salah Mezlini; Akshay Amaranath Hajjaji

Addresses: Université de Toulouse, INSA, UPS, Mines d'Albi, ISAE, ICA (Institut Clément Ader), IUTA GMP Toulouse, 133 c Avenue de Rangueil, 31077 Toulouse, France; Laboratoire Génie Mécanique, École Nationale d'Ingénieurs de Monastir, Université de Monastir, 5000, Tunisia ' Université de Toulouse, INSA, UPS, Mines d'Albi, ISAE, ICA (Institut Clément Ader), IUTA GMP Toulouse, 133 c Avenue de Rangueil, 31077 Toulouse, France ' Aerospace Engineering, Indian Institute of Science (IISc), Bangalore – 12, Karnataka, India ' Laboratoire Génie Mécanique, École Nationale d'Ingénieurs de Monastir, Université de Monastir, 5000, Tunisia ' Aerospace Engineering, Indian Institute of Science (IISc), Bangalore – 12, Karnataka, India

Abstract: Drilling damage, such as delamination at the hole exit, is known to adversely affect the load carrying capability of a structure resulting in reduced endurance limits and overall reduction in structural integrity. In this context, the present work studies the influence of temperature of machining on the critical thrust force responsible for delamiantion at the hole exit. An analytical model considering thermo-elastic field equations has been established with the aim of predicting the critical thrust force. The validation of this model has been conducted at room temperature via punching tests carried out on carbon fibre epoxy multi-directional composite laminates. Some difference in predictions exists which are mainly attributed to the variability in ply thicknesses due to the manufacturing process. Such an analysis underscores the need to explicitly account for machining temperature effects on machining damage characterisation.

Keywords: drilling damage; thermo-mechanical properties; force prediction; critical thrust force; exit-ply delamination; composite laminates; structural integrity; hole exit; machining temperature; punching tests; ply thickness.

DOI: 10.1504/IJMMM.2016.075464

International Journal of Machining and Machinability of Materials, 2016 Vol.18 No.1/2, pp.77 - 98

Received: 29 Apr 2015
Accepted: 27 Jul 2015

Published online: 23 Mar 2016 *

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