A Nonlinear Analysis Interpretation of Off-Axis Test Results in Metal Matrix Composites

Jalees Ahmad,Unni Santhosh,Swamy Chandu

doi:10.3390/jcs4030127

Abstract

A unit-cell based micromechanics approach is used to perform nonlinear finite element analyses of off-axis tensile tests on an SCS-6/Ti-6Al-4V composite. The results are used in predicting the global deformation response of the composite that includes the effect of fiber-matrix interface damage. The predictions are compared with laboratory test data of uniaxial off-axis specimens. Based on the comparison, it is found that the procedure effectively predicts global composite response with reasonable accuracy under a general multiaxial stress state.

Highlights

Titanium-based metal matrix composites (MMCs) offer excellent potential for high-temperature applications that require a combination of high strength, stiffness and toughness [1,2]
The off-axis tensile (OAT) test is considered as a viable method for characterizing the global, multiaxial stress-strain response of composites in the nonlinear deformation range [7,8,9,10,11]
Attempts are being made to formulate theoretical models that can be used in nonlinear stress analysis of continuous fiber and particulate MMCs under multiaxial stress states [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]

Summary

Introduction

Titanium-based metal matrix composites (MMCs) offer excellent potential for high-temperature applications that require a combination of high strength, stiffness and toughness [1,2]. Particulate composites have been modeled using finite-element analysis by either mapping three-dimensional images of the microstructure to capture details of particle shape and distribution [26] or by randomly generating the particle size and distribution [27] While this approach yields finer details of material behavior at the microstructural level as compared to other models, they are computationally inefficient for the analysis of large structures. The uniformity of stress state enables consideration of a ‘unit-cell’ based micromechanics analysis approach for predicting nonlinear deformation response of an OAT specimen. In such an approach, the unit-cell consists of a single fiber surrounded by a matrix region. The predicted stress-strain response of the composite is compared with laboratory test data on SCS-6/Ti-6Al-4V eight-ply composite

Approach

Determination of Internal State of Stress

Results and Discussion

Conclusions