scholarly journals Effect of Seismic P-Waves Propagation on Circular Tunnels in Layered Ground

During propagation of the compression seismic P-waves, the tunnels are subjected to ovaling deformations. In cases where the soil stiffness is varying along the tunnel cross-section, tunnel lining may take sharper deformed shapes and subjected to magnified bending moments and thrust forces. This paper investigates the effect of the soil stratification on the seismic behavior of circular tunnels under P-waves loading. A 2D finite element models with time history earthquake (EQ) analysis were performed accounting for different tunnel/soil interface slippage conditions. The finite element analysis results were compared with recent analytical solution for calculating the seismic forces of the tunnel lining. The study proved that soil stratification has a great effect on the tunnel seismic forces and it should be considered in the analysis and design. Illustrative curves were presented in this paper to give approximate magnification factors for the anticipated forces. It should be used as a guide in the preliminary design stage.

Author(s):  
Shiyong Yang ◽  
Kikuo Nezu

Abstract An inverse finite element (FE) algorithm is proposed for sheet forming process simulation. With the inverse finite element analysis (FEA) program developed, a new method for concurrent engineering (CE) design for sheet metal forming product and process is proposed. After the product geometry is defined by using parametric patches, the input models for process simulation can be created without the necessity to define the initial blank and the geometry of tools, thus simplifying the design process and facilitating the designer to look into the formability and quality of the product being designed at preliminary design stage. With resort to a commercially available software, P3/PATRAN, arbitrarily three-dimensional product can be designed for manufacturability for sheet forming process by following the procedures given.


2014 ◽  
Vol 695 ◽  
pp. 535-538
Author(s):  
Muhammad Zahir Hassan ◽  
Abdul Munir Fudhail ◽  
Mohd Azli Salim

All-terrain vehicle is famously used for various purposes such as in civilian and military. The use of finite element analysis in a preliminary design stage has been demonstrated to be cost and time effective. In this paper, the finite element analysis of a brake disc for All-Terrain-Vehicle (ATV) is demonstrated. Eulerian-Lagrangian method was employed in this work where simple annular ring was used as the disc model. This study is limited to thermal and contact analysis between the disc and brake pad. The results in term of temperature and stresses distribution is obtained and presented. Moreover, the lateral displacement of the disc due to the friction contact is also shown. These results are then used to as a technical guideline in designing brake system for a fully customized ATV


Author(s):  
Yuan Jie Lua ◽  
Robert H. Sues

Mechanistic pavement analysis and design based on either layered elastic analysis (LEA) or the finite element method (FEM) is increasingly being used to replace the empirical design process. The simplifying assumptions of a uniform, homogeneous layer of linear material used in LEA can render its analysis inaccurate for real pavement structures. The FEM is more attractive for structural analysis of pavements; the generality of the FEM also allows both the use of comprehensive material models and modeling of the spatial variability that exists in pavement systems. To date, spatial variability and uncertainty are ignored in pavement system finite element analyses. Ignoring spatial variability and uncertainty implies a false sense of accuracy in the results and can lead to inaccurate assessment of the pavement. The first application of the probabilistic finite element method to pavement response analysis and life prediction and the first investigation of the effects of spatial variability on pavement life prediction are presented. It is concluded that the probabilistic FEA, with spatial variability, is a more accurate representation of the true physical condition and leads to results that are less conservative than those obtained with probabilistic LEA.


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