scholarly journals STUDY ON THE ELASTO-PLASTIC FLEXURAL BEHAVIOUR OF REINFORCED CONCRETE MEMBERS SUBJECTED TO AXIAL LOAD : Part III Moment-Curvature Relation under Cyclic Bending Moment

1967 ◽  
Vol 136 (0) ◽  
pp. 15-21,49
Author(s):  
MINORU YAMADA ◽  
HIROSHI KAWAMURA
Author(s):  
Yanping Yao ◽  
Ming-Wan Lu ◽  
Xiong Zhang

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.


Author(s):  
Ming Zhang ◽  
Yanyao Jiang ◽  
Chu-Hwa Lee

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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