Plastic Collapse Behavior and Remaining Life Assessment of Statically Indeterminate Cracked Beam - Using the Limit Analysis Technique

Sung-Po  Liu

doi:10.6180/jase.2012.15.4.03

Plastic Collapse Behavior and Remaining Life Assessment of Statically Indeterminate Cracked Beam - Using the Limit Analysis Technique

Mechanical Engineering

Sung-Po Liu This email address is being protected from spambots. You need JavaScript enabled to view it.¹

¹Department of Mechanical Engineering, Ching Yun University, Jung-Li, Taiwan 320, R.O.C.

Received: January 2, 2012
Accepted: March 22, 2012
Publication Date: December 1, 2012

Download Citation: ||https://doi.org/10.6180/jase.2012.15.4.03

ABSTRACT

This paper develops an analytical model for the plastic collapse of a statically indeterminate rectangular beam containing a crack. Limit analysis, elastic-plastic fracture mechanics, compliance, and J-integral concepts are used to study J_IC and dJ/da, which influence the crack propagation in this study. The relations among the plastic hinge, applied load, linear displacement, rotational angle, and crack growth lead to a better understanding of the problem. The LBB (Leak-Before-Break) characteristic of the statically indeterminate rectangular beam is valid if the crack propagates before plastic collapse. Unstable ductile fractures occur when the crack propagates before plastic collapse or when dJ/da is smaller than the minimum critical value. The life span of the crack extension to collapse can be computed by the 4^th order of the Runge-Kutta method. The information provided in this study can be applied to safe and reliable design structures. These analyses and design strategies developed in this paper are useful for the safety performance of a structural beam under crack deformation.

Keywords: Elastic-Plastic Fracture Mechanics, Crack Propagation Resistance, Crack Growth, Statically Indeterminate Beam, Leak-Before-Break

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