자료유형  

 학위논문

Control Number  

0016935236

International Standard Book Number  

9798380720397

Dewey Decimal Classification Number  

600

Main Entry-Personal Name  

Vivekanandan, Vignesh.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(132 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-05, Section: B.

General Note  

Advisor: El-Azab, Anter.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Self-organized dislocation structures in deforming metals have a strong influence on the mechanical response of metals. However, accurate prediction of these patterns remains a challenge due to the complex dynamic and multiscale nature of the underlying process. This dissertation focuses on the development of a theoretical framework for continuum dislocation dynamics (CDD) models to predict dislocation microstructure formation at small strains, along with corresponding numerical simulation results. CDD models have the capability to incorporate plasticity physics spanning different time and length scales while capturing the dislocation motion explicitly within reasonable computational time. A typical model consists of two components: crystal mechanics, formulated as an eigenstrain problem, and dislocation dynamics, treated as a transport-reaction problem. In the first part of the thesis, a novel framework is introduced to solve the dislocation transport by decoupling the system of transport-reaction equations and enforcing the dislocation continuity constraint on individual slip systems. The results obtained from this framework demonstrate high accuracy and computational efficiency, significantly enhancing the predictive capabilities of the model. Building upon the framework, a statistical analysis of stress fluctuations in discrete dislocation dynamics (DDD) simulations is conducted to understand the relationship between coarse-grained average stress and local stress states. This analysis is motivated by the need to accurately capture dislocation reactions, such as cross-slip, which strongly depend on the local stress state, using the coarse-grained approach in CDD. The results revealed that the difference between the local and the coarse-grained states can be characterized using a Cauchy distribution. Consequently, a novel strategy is proposed to incorporate these statistical characteristics into the CDD model, yielding cross-slip rate predictions that align well with DDD results. In the final part of the study, the developed framework is applied to investigate the dislocation pattern formation during the early stages of cyclic loading. The simulation results successfully capture the formation of dislocation vein like structure and provide insights regarding the formation of labyrinth structure observed in experiments during cyclic loading at saturated state.

Subject Added Entry-Topical Term  

Metals.

Subject Added Entry-Topical Term  

Stress state.

Subject Added Entry-Topical Term  

Partial differential equations.

Subject Added Entry-Topical Term  

Strain hardening.

Subject Added Entry-Topical Term  

Crack initiation.

Subject Added Entry-Topical Term  

Stress-strain curves.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Microstructure.

Subject Added Entry-Topical Term  

Deformation.

Subject Added Entry-Topical Term  

Crystals.

Subject Added Entry-Topical Term  

Mechanics.

Subject Added Entry-Topical Term  

Probability distribution.

Subject Added Entry-Topical Term  

Shear stress.

Subject Added Entry-Topical Term  

Statistics.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 85-05B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:639086