A parametric study of delaminations in an aluminum-lithium alloy

Hamel, Sean F.

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https://hdl.handle.net/2142/16734 Copy

Description

Title

A parametric study of delaminations in an aluminum-lithium alloy

Author(s)

Hamel, Sean F.

Issue Date

2010-08-20T17:56:15Z

Director of Research (if dissertation) or Advisor (if thesis)

Beaudoin, Armand J.

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Aluminum Lithium (AlLi)
• Delamination Aluminum Lithium

Abstract

The significant advantages in weight reduction and increased strength have placed advanced aluminum-lithium alloys at the forefront of aerospace materials research. Delaminations in these alloys play a significant role in their fracture processes. Therefore, a more complete understanding of the factors that influence the behavior of these delaminations and their corresponding effect on the primary crack behavior is the motivation for this study. The effects of texturing from mechanical processing, and the varying fracture toughness from heat treatments are the focus of the current study. An elasto-viscoplastic model, based on the mechanical threshold state variable, was adopted to describe the constitutive behavior of these alloys, and was incorporated into a small-scale yield bi-crystal finite element model. This finite element model was then enhanced by inserting cohesive zone elements into planes where cracks are expected. These specialized elements not only simulate the initiation of cracks, but dynamically illustrate their subsequent growth as well. This framework was used to conduct parametric studies on the effects of texturing and fracture toughness on the behavior of the primary crack and any delaminations that may form in the crack-divider configuration.

Graduation Semester

2010-08

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http://hdl.handle.net/2142/16734

Copyright and License Information

Copyright 2010 Sean Hamel

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