Water distribution networks are essential components of water supply systems. The combination of pipe structural deterioration and mechanics leads to the failure of pipelines. A physical model for estimating the pipe ...Water distribution networks are essential components of water supply systems. The combination of pipe structural deterioration and mechanics leads to the failure of pipelines. A physical model for estimating the pipe failure must include both the pipe deterioration model and mechanics model. Winkler pipe-soil interaction (WPSI), an analytical mechanics model developed by Rajani and Tesfamariam (2004), takes external and internal loads, temperature changes, loss of bedding support, and the elastoplastic effect of soil into consideration. Based on the WPSI model, a method to evaluate the elastic and plastic areas was proposed in the present study. An FEM model based on pipe-soil interaction (PSI) element was used to verify the analytical model. Sensitivity analyses indicate that the soft soil, long pipe and high temperature induced the axial plastic deformation more likely, which, however, may not occur in normal scenarios. The soft soil, pipes in small diameters, long unsupported bedding are prone to form flexural plastic area. The results show that the pipes subjected to the same loads have smaller stresses in the elastoplastic analysis than elastic analysis. The difference, however, is slight.展开更多
To improve the bending load-carrying capacity （ BLCC） of under-matched butt joint under four-point bending load in the elastic stage, the shape design of the reinforcement is studied based on the theoretics of mecha...To improve the bending load-carrying capacity （ BLCC） of under-matched butt joint under four-point bending load in the elastic stage, the shape design of the reinforcement is studied based on the theoretics of mechanics of materials. The concept, criterion, realization condition and design proposal of equal bending load-carrying capacity （EBLCC） are put forward. The theoretical analysis results have been verified by the finite element method. The simulation results are coincident basically with the ones of theoretical analysis. The research results show that the shape design of the reinforcement of EBLCC can improve BLCC of under-matched butt joint and the unilateral-side type reinforcement can replace double-side symmetry展开更多
基金Project supported by the National Natural Science Foundation of China (No. 50278088)the Program for New Century Excellent Talents in University (No. NCET-04-0525), China
文摘Water distribution networks are essential components of water supply systems. The combination of pipe structural deterioration and mechanics leads to the failure of pipelines. A physical model for estimating the pipe failure must include both the pipe deterioration model and mechanics model. Winkler pipe-soil interaction (WPSI), an analytical mechanics model developed by Rajani and Tesfamariam (2004), takes external and internal loads, temperature changes, loss of bedding support, and the elastoplastic effect of soil into consideration. Based on the WPSI model, a method to evaluate the elastic and plastic areas was proposed in the present study. An FEM model based on pipe-soil interaction (PSI) element was used to verify the analytical model. Sensitivity analyses indicate that the soft soil, long pipe and high temperature induced the axial plastic deformation more likely, which, however, may not occur in normal scenarios. The soft soil, pipes in small diameters, long unsupported bedding are prone to form flexural plastic area. The results show that the pipes subjected to the same loads have smaller stresses in the elastoplastic analysis than elastic analysis. The difference, however, is slight.
文摘To improve the bending load-carrying capacity （ BLCC） of under-matched butt joint under four-point bending load in the elastic stage, the shape design of the reinforcement is studied based on the theoretics of mechanics of materials. The concept, criterion, realization condition and design proposal of equal bending load-carrying capacity （EBLCC） are put forward. The theoretical analysis results have been verified by the finite element method. The simulation results are coincident basically with the ones of theoretical analysis. The research results show that the shape design of the reinforcement of EBLCC can improve BLCC of under-matched butt joint and the unilateral-side type reinforcement can replace double-side symmetry
