A continuum damage mechanics model for woven composites

Master Thesis (2017)
Author(s)

C. Gámir Huguet (TU Delft - Aerospace Engineering)

Contributor(s)

Sonell Shroff – Mentor

Claudio Lopes – Mentor

Sergio Turteltaub – Graduation committee member

J. J.E. Teuwen – Graduation committee member

Faculty
Aerospace Engineering
Copyright
© 2017 Carlos Gámir Huguet
More Info
expand_more
Publication Year
2017
Language
English
Copyright
© 2017 Carlos Gámir Huguet
Graduation Date
28-07-2017
Awarding Institution
Delft University of Technology
Programme
['Aerospace Engineering | Structures and Materials']
Faculty
Aerospace Engineering
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

A novel continuum damage mechanics model for 2D woven fabrics has been developed and implemented in a VUMAT subroutine for Abaqus/Explicit. The model takes into account the shear non-linearity, the toughening mechanisms associated to tensile failure, and the influence of shear stresses in the initiation and propagation of tensile damage.

The non-linear shear behavior is reproduced by means of a Ramberg-Osgood equation. Permanent deformation, and the degradation of the secant shear modulus associated to the accumulation of matrix damage have been coupled to the formulation of this unidimensional plasticity law. The physical reference required to define completely the shear constitutive response proposed can be obtained from the experimental tensile test of ±45 off-axis coupons. Failure initiation in tension is identified using Hashin's quadratic failure criterion, which accounts for the interaction of shear stresses in the promotion of tensile failure. A bilinear softening relation was selected to represent the combination of fibre breakage and toughening mechanisms characteristic of the intralaminar tensile fracture of these materials. Effort was placed on the development of a procedure for calibrating the softening relation associated to this failure mode. Specifically, this work addresses the applicability of linking the definition of a bilinear tensile damage law in homogenized continuum damage mechanics models for woven composites to the shape of a crack growth resistance curve measured with compact tension tests.

The constitutive model was validated including it in a set of finite element models of unnotched and open hole coupons with different multistacking sequences, under quasi-static tensile loading conditions, and comparing the results obtained by the simulation of the coupons against an experimental benchmark. A good correlation was achieved between the ultimate strength predicted with finite element analysis and the experimental data.

Files

MSc_Thesis_CGamir.pdf
(pdf | 5.36 Mb)
License info not available