Experimental Study on the Pullout Resistance of Smooth Steel Strip Reinforcement with Transverse Members

This paper presents an experimental study on the pullout resistance of a newly improved reinforcement. The applied reinforcement was a smooth steel strip reinforcement with transverse members used to improve the pullout-resistance problems of the smooth steel strip reinforcement. The pullout and bearing resistance of the improved reinforcement were evaluated using results of large-scale pullout tests. The evaluation result confirmed that the bearing resistance of the improved reinforcement was about 33–66% of the total pullout resistance, and it had an evenly distributed friction and bearing resistance. The bearing bond coefficient, considering the interference effect, gradually converged when normal stress was higher than a certain value. This result confirmed that the increment of interference effect is caused by the increment of the transverse member and normal stress. In the pullout-resistance evaluation of the improved reinforcement, a number of transverse members can be predicted using the relationship between bearing-resistance stress and the bearing bond coefficient due to normal stress, which can be applied as a reasonable prediction method.

Fast Meshless Solution With Lumped Friction for Water Hammer

The water hammer in pipelines, with the absence of fluid friction, could be solved by a time-domain exact solution, using a simple recursive process. No computational grid was needed, but the calculation time cost was extremely high. Its improved method, named as the fast meshless solution (FMS), was developed to speed the computation by introducing the time-line interpolation. For the purpose of practical applications, the attempt to consider fluid friction in the FMS is presented here. As there is no mesh grid in the distance-time plane, the distributed friction model can not be employed upon the presented method directly. The fluid friction lumped at the pipe end is proposed, and both steady and unsteady friction are studied. A benchmark problem of the water hammer in a reservoir-pipe-valve (RPV) system is employed for the validation and comparison. The water hammer considering lumped friction can be calculated fast by the FMS, and the accuracy is acceptable. The method discussed here may be of interest in a quick assessment of the piping water hammer.

Improved Exact Solution for Axial FSI Model of Liquid-Pipes Considering Complex Constraints

The fluid-structure interaction (FSI) can be observed significantly in the axial vibration of the liquid-filled pipe system. When distributed friction was neglected, the model could be solved with an exact solution without numerical error, developed from the method of characteristics (MOC). Then time-line interpolations have been employed to reduce the high time cost and retain the accuracy, named as the improved exact solution. For the purpose of practical applications, series connection of double-pipes is discussed in this paper. And complex constraints, including elastic, damping and inertial effects at connections, are studied. Models and methods are validated by numerical cases.