Study on implicit composite element method for seepage analysis in underground engineering

2015 ◽  
Vol 58 (10) ◽  
pp. 1617-1626 ◽  
Author(s):  
LingZi Li ◽  
Ming Xiao
Keyword(s):  
Underground Engineering ◽  
Seepage Analysis ◽  
Composite Element ◽  
Composite Element Method ◽  
Element Method

Research on Key Algorithms for Seepage Analysis Using Composite Element Containing Drainage Holes

2013 ◽  
Vol 838-841 ◽  
pp. 1693-1697
Author(s):  
Gui Sheng Xu ◽  
Jian Qiang Guo
Keyword(s):  
Permeability Coefficient ◽  
Adaptive Method ◽  
High Permeability ◽  
Seepage Analysis ◽  
Hierarchical Order ◽  
Composite Element ◽  
Composite Element Method ◽  
Element Method

For seepage analysis using Composite Element Method(CEM), the drainage holes are treated as “air sub-elements” with high permeability contained in the conventional rock(soil) element, which is called “composite element”. To ensure the validity and correctness of the calculated results, the “permeability coefficient” of drainage holes and transmissibility coefficient of the interface between rock(soil) and drainage holes are studied and some reasonable suggestions are given. To improve the calculation precision and efficiency of CEM, the p-version adaptive method is studied and the corresponding algorithm of upgrade the hierarchical order and accelerating convergence are implemented in the CEM.

scholarly journals Homotopy Iteration Algorithm for Crack Parameters Identification with Composite Element Method

2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Ling Huang ◽  
Zhongrong Lv ◽  
Weihuan Chen ◽  
Jike Liu
Keyword(s):  
Dynamic Responses ◽  
Iteration Algorithm ◽  
Crack Model ◽  
Open Crack ◽  
Time Duration ◽  
Cracked Beam ◽  
Composite Element ◽  
Direct Integration Method ◽  
Composite Element Method ◽  
Element Method

An approach based on homotopy iteration algorithm is proposed to identify the crack parameters in beam structures. In the forward problem, a fully open crack model with the composite element method is employed for the vibration analysis. The dynamic responses of the cracked beam in time domain are obtained from the Newmark direct integration method. In the inverse analysis, an identification approach based on homotopy iteration algorithm is studied to identify the location and the depth of a cracked beam. The identification equation is derived by minimizing the error between the calculated acceleration response and the simulated measured one. Newton iterative method with the homotopy equation is employed to track the correct path and improve the convergence of the crack parameters. Two numerical examples are conducted to illustrate the correctness and efficiency of the proposed method. And the effects of the influencing parameters, such as measurement time duration, measurement points, division of the homotopy parameter and measurement noise, are studied.

Vibration Response Analysis of a Stepped Beam with Crack Using Composite Element Method

2011 ◽  
Vol 199-200 ◽  
pp. 835-838
Author(s):  
Xu Bin Lu ◽  
Zhong Rong Lv ◽  
Ji Ke Liu
Keyword(s):  
Forced Vibration ◽  
Vibration Response ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Crack Model ◽  
Composite Element ◽  
Stiffness Reduction ◽  
Stepped Beam ◽  
Composite Element Method ◽  
Element Method

The composite element method is utilized to discretise a stepped Euler-Bernoulli beam with a crack. The local stiffness reduction due to the crack is introduced by using a simplified crack model. The finite element equation for the forced vibration analysis is obtained using the composite element method (CEM). The forced vibration response of the cracked stepped beam is numerically calculated using Newmark integration method. Numerical results indicate that the position and depth of a crack affects the low and high natural frequencies and modes of a cantilever beam, respectively. And the position of the crack has significant effects on the dynamic responses of the beam.

The Research and Application on the Efficient and Local Accuracy Decrease Algorithm in Underground Engineering

2011 ◽  
Vol 105-107 ◽  
pp. 1358-1366
Author(s):  
Wei Feng Wang ◽  
Jing Bin Ye ◽  
Sai Ying Shi ◽  
Qing Zhong Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mesh Generation ◽  
Underground Engineering ◽  
Gaussian Integration ◽  
Finite Element Software ◽  
Composite Element ◽  
Analysis Theory ◽  
Local Accuracy ◽  
Element Method

This paper studies the basic principles of finite element method, then researches on the core algorithm of finite element method, according to Saint-Venant principle, introduce the concept of composite element, proves that if the element is composite element, the original integration is still able to calculate. Based on the feature that numerical integration solution is in fact the Gaussian integration points are calculated, we endow element internal with different material property values according to the different location artificially. This is the efficient and local accuracy decrease algorithm. The algorithm is able to simplify the work of mesh generation, improve the overall computing efficiency, is especially suitable for underground engineering, and we can quickly get the overall characteristics of the structure that we are most concerned about. Finally, builds the actual examples of underground engineering, uses the finite element software Ansys and the efficient and local accuracy decrease algorithm program to calculate the actual examples respectively, compares the results between them, expounds and set the analysis theory and relevant principles, makes conclusion: the efficient and local accuracy decrease algorithm can simplify mesh generation, improve the overall computing efficiency; and it can be used in underground engineering very well.

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