Inelastic Behavior of Steel Beam-Columns Subject to Varying Axial Force and Cyclic Bending Moment

1998 ◽  
pp. 45-54
Author(s):  
S. Yamazaki ◽  
S. Mimani
Keyword(s):  
Axial Force ◽  
Bending Moment ◽  
Steel Beam ◽  
Inelastic Behavior ◽  
Cyclic Bending ◽  
Beam Columns ◽  
Cyclic Bending Moment

Load Regime Diagram of a Pipe With Cyclically Plastic Bending

2002 ◽  
Author(s):  
Yanping Yao ◽  
Ming-Wan Lu
Keyword(s):  
Axial Force ◽  
Bending Moment ◽  
Boundary Curve ◽  
Plastic Behavior ◽  
Cyclic Bending ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Load Regime ◽  
Reversed Cyclic ◽  
Cyclic Bending Moment

The criteria of piping seismic design based on linear elastic analysis has been proved to be conservative, which is mainly because the influence of plastic deformation on piping dynamic response is neglected. In the present paper, a pipe under seismic excitation is simplified as an beam with tubular cross section subjected to steady axial force and fully reversed cyclic bending moment, and the elastic-plastic behavior of the pipe is studied. Various behavior of the pipe under different combinations of axial force and cyclic bending moment is discussed and the boundary curve equations between them are obtained. Also the load regime diagram for a pipe which is formed by the boundary curve equations in the loading plane is given, from which the elastic-plastic behavior of the pipe can be determined directly.

Inelastic Behavior of Pipe Subjected to Steady Extension and Cyclic Bending

2003 ◽  
Author(s):  
Yanping Yao ◽  
Ming-Wan Lu ◽  
Xiong Zhang
Keyword(s):  
Cross Section ◽  
Axial Load ◽  
Bending Moment ◽  
Boundary Curve ◽  
Plastic Behavior ◽  
Inelastic Behavior ◽  
Cyclic Bending ◽  
Load Regime ◽  
Two Parameters ◽  
Cyclic Bending Moment

The inelastic behavior of a pipe subjected to steady axial force and cyclic bending moment, such as shakedown, plastic fatigue, ratcheting and plastic collapse, is studied. By using two parameters c and d, which indicate the elasto-plastic interfaces of beam cross section, the boundary curve equations between various types of inelastic behavior are derived. The results are suitable for beams of any shaped cross section with two orthogonal symmetric axes. Especially, the load regime diagram for a pipe is obtained, which indicates the elasto-plastic behavior of the pipe under given combination of axial load and cyclic bending moment intuitively.

Finite Element Modeling of Self-Loosening of Bolted Joints

2004 ◽  
Author(s):  
Ming Zhang ◽  
Yanyao Jiang ◽  
Chu-Hwa Lee
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Bending Moment ◽  
Shear Loading ◽  
Transverse Load ◽  
Fe Model ◽  
Bolted Joint ◽  
Cyclic Bending ◽  
Second Stage ◽  
Cyclic Bending Moment

A three-dimensional finite element (FE) model with the consideration of the helix angle of the threads was developed to simulate the second stage self-loosening of a bolted joint. The second stage self-loosening refers to the graduate reduction in clamping force due to the back-off of the nut. The simulations were conducted for two plates jointed by a bolt and a nut and the joint was subjected to transverse or shear loading. An M12×1.75 bolt was used. The application of the preload was simulated by using an orthogonal temperature expansion method. FE simulations were conducted for several loading conditions with different preloads and relative displacements between the two clamped plates. It was found that due to the application of the cyclic transverse load, micro-slip occurred between the contacting surfaces of the engaged threads of the bolt and the nut. In addition, a cyclic bending moment was introduced on the bolted joint. The cyclic bending moment resulted in an oscillation of the contact pressure on the contacting surfaces of the engaged threads. The micro-slip between the engaged threads and the variation of the contact pressure were identified to be the major mechanisms responsible for the self-loosening of a bolted joint. Simplified finite element models were developed that confirmed the mechanisms discovered. The major self-loosening behavior of a bolted joint can be properly reproduced with the FE model developed. The results obtained agree quantitatively with the experimental observations.

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