Civil Engineering ETDs

Publication Date

Fall 12-15-2018

Abstract

Ductile failure of metals has been the focus of research efforts within academia and industry for many years since it is tremendously important for understanding the failure of structures under extreme loading conditions. However, limited research has been dedicated to elevated temperature ductile failure, which is critical for evaluating catastrophic events such as industrial, structural or shipping vessel fires. A detailed investigation was conducted on the structural response of Duplex Stainless Steel at elevated temperatures. The temperature dependence of elastic modulus, yield strength, ultimate strength, and ductility was measured up to 1000°C and a continuum damage plasticity model was developed. Experiments were conducted to validate the model for predicting the failure of loaded structures subjected to transient heating. The model captured crack initiation locations, failure times and temperatures within 5% for panel specimens in tension. The continuum damage plasticity model was then validated for predicting the critical heated zone size which results in catastrophic failure of pressure vessels, providing insight into the criticality analysis of thermal protection systems. Catastrophic failure during fully engulfing fuel fires can be very destructive when a boiling liquid expanding vapor explosion occurs. The predictive capability developed during this research enables the design of hazard mitigation solutions and damage inspection requirements for industrial fires. This is the first known capability presented in the literature for predicting the transition from local to catastrophic failure in un-cracked pressure vessels and pipelines due to localized heating, which has historically focused on the criticality of existing cracks under ambient conditions.

Keywords

Temperature, Pressure Vessel, Stainless Steel, Fracture, Damage, Crack, Pipeline

Document Type

Dissertation

Language

English

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

First Committee Member (Chair)

Tang-Tat Ng

Second Committee Member

Fernando Moreu

Third Committee Member

Yu-Lin Shen

Fourth Committee Member

Hugh Denham

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