Internal State Variable Modeling and Experiments of Structure-Property Relationships of Iron Based Alloys

Author

Shane A. Brauer

Issuing Body

Mississippi State University

Advisor

Horstemeyer, Mark F.

Committee Member

Oppedal, Andrew L.

Committee Member

Kennan Crane, Kennan Charles.

Committee Member

Rhee, Hongjoo.

Date of Degree

5-6-2017

Document Type

Dissertation - Open Access

Major

Mechanical Engineering

Degree Name

Doctor of Philosophy

College

James Worth Bagley College of Engineering

Department

Department of Mechanical Engineering

Abstract

An investigation of the microstructure-mechanical property relationships for gray cast iron and a vintage ASTM A7 steel are presented herein. Gray cast iron was shown to have a moderate sensitivity to strain rate and a large disparity in behavior between compression, tension, and torsion. ASTM A7 steel was shown to behave in a more complex manor with the strain rate sensitivity having a negative relationship in tension and positive relationship in compression and torsion, the tensile stress-state producing the highest stress response, and the material producing a higher stress response when exposed to elevated temperatures. The counterintuitive behavior observed in A7 steel was attributed to dynamic strain aging. The Mississippi State University Internal State Variable Plasticity-Damage model was updated to accurately capture negative strain rate sensitivity and DSA embrittlement by developing kinematic, thermodynamic, and kinetic constitutive relationships for dynamic strain aging. A parametric study was performed to elucidate the behavior of the new internal state variable for dynamic strain aging. Gray cast iron was successfully calibrated to a pre-DSA version of the plasticity-damage model and A7 steel was successfully calibrated to the updated plasticity-damage model.

URI

https://hdl.handle.net/11668/16589

Comments

torsion||tension||High strain rate||Gray cast iron||ASTM A7 steel||stress-state||dynamic strain aging||structure-property||negative strain rate sensitivity||stress-strain||internal state variables||plasticity||constitutive model||damage||compression

Recommended Citation

Brauer, Shane A., "Internal State Variable Modeling and Experiments of Structure-Property Relationships of Iron Based Alloys" (2017). Theses and Dissertations. 2782.
https://scholarsjunction.msstate.edu/td/2782