Doctoral Dissertations

Jian Chen

Abstract

"Radial forging is an important manufacturing process to produce large cannon barrels. It is used to improve the material properties and reduce the porosity of the billet. The objective of this study is to develop finite element models to investigate the behavior of the workpiece and predict the elimination of void defects in the radial forging process. A nonlinear coupled finite element model has been developed to study the behavior of a large-diameter tube subjected to mechanical and thermal loadings in hot radial forging. The model is formulated in a three-dimensional frame, accounting for both axial and circumferential effects. A rate-dependent material model is used to describe the viscoplastic behavior of a workpiece subject to high temperature and large strain. The simulation results are compared with previously published experimental and two dimensional axi-symmetric simulation results. This work also develops a comprehensive three-dimensional model to predict the degree to which void defects are eliminated in the cold rolling process. It compares experimental results to the finite element predictions to validate the model. The void reduction predictions of the finite element analysis agree closely with the experimental findings. Neural network has been used to establish the relationship between the process parameters and the void reduction. Finally the previous model has been extended to examine the mechanism of void deformation subjected to large deformation in hot radial forging. It investigates systematically the effects of void location, mandrel, die shape, and reduction in tube thickness on the final void reduction. The model is verified by comparison with experimental findings. All the simulation results provide a valuable procedure for the design of the hot radial forging process"--Abstract, page iv.

Advisor(s)

Chandrashekhara, K.

Committee Member(s)

Dharani, Lokeswarappa R.
Du, Xiaoping
Tsai, Hai-Lung
Richards, Von

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Sponsor(s)

Benét Laboratories
Missouri University of Science and Technology. Department of Mechanical and Aerospace Engineering

Publisher

Missouri University of Science and Technology

Publication Date

2011

Journal article titles appearing in thesis/dissertation

  • Three-dimensional nonlinear finite element analysis of hot radial forging process for large diameter tubes/li>
  • Void closure prediction in cold rolling using finite element analysis and neural network
  • Study of void closure in rot radial forging process using 3D nonlinear finite element analysis

Pagination

xi, 135 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2011 Jian Chen, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Forging machinery -- Mathematical models
Founding -- Defects -- Mathematical models
Nonlinear mechanics
Finite element method

Thesis Number

T 10162

Print OCLC #

861227583

Electronic OCLC #

908636695

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