scholarly journals Influence of Seismic Loading on Segment Opening of a Shield Tunnel

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yang Chun-shan ◽  
Mo Hai-hong ◽  
Chen Jun-sheng ◽  
Wang Yi-zhao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Calculation Method ◽  
Seismic Loading ◽  
Shield Tunnel ◽  
Seismic Action ◽  
One Dimensional ◽  
Dynamic Finite Element ◽  
Different Depths ◽  
Continuous Theory

The influence of seismic loading on segment opening of a shield tunnel was explored using the dynamic finite element method to analyze the distribution of segment opening under multidirectional seismic loading, combined with a typical engineering installation. The calculation of segment opening was deduced from equivalent continuous theory and segment opening was obtained through calculations. The results show that the scope of influence of the foundation excavation on segment opening is mainly resigned to within 5 segment rings next to the diaphragm wall and 4 joints nearest the working well when the tunnel is first excavated followed by the working well in the excavation order. The effect of seismic loading on segment opening is significant, and the minimum increase of the maximal segment opening owing to seismic loading is 16%, while that of the average opening is 27%. Segment opening under bidirectional coupled seismic loading is significantly greater than that under one-dimensional seismic loading. On the basis of the numerical calculations, the seismic acceleration and segment opening caused by seismic action were normalized, and a new calculation method was proposed for predicting the maximal segment opening of a shield tunnel at different depths under conditions of seismic loading.

scholarly journals Finite Element Analysis of Thermoelastic Contact Stability

1994 ◽  
Vol 61 (4) ◽  
pp. 919-922 ◽  
Author(s):  
Taein Yeo ◽  
J. R. Barber
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Steady State ◽  
Eigenvalue Problem ◽  
Linear Perturbation ◽  
Dimensional System ◽  
The Finite Element Method ◽  
One Dimensional ◽  
Thermoelastic Contact ◽  
Element Method

When heat is conducted across an interface between two dissimilar materials, theimoelastic distortion affects the contact pressure distribution. The existence of a pressure-sensitive thermal contact resistance at the interface can cause such systems to be unstable in the steady-state. Stability analysis for thermoelastic contact has been conducted by linear perturbation methods for one-dimensional and simple two-dimensional geometries, but analytical solutions become very complicated for finite geometries. A method is therefore proposed in which the finite element method is used to reduce the stability problem to an eigenvalue problem. The linearity of the underlying perturbation problem enables us to conclude that solutions can be obtained in separated-variable form with exponential variation in time. This factor can therefore be removed from the governing equations and the finite element method is used to obtain a time-independent set of homogeneous equations in which the exponential growth rate appears as a linear parameter. We therefore obtain a linear eigenvalue problem and stability of the system requires that all the resulting eigenvalues should have negative real part. The method is discussed in application to the simple one-dimensional system of two contacting rods. The results show good agreement with previous analytical investigations and give additional information about the migration of eigenvalues in the complex plane as the steady-state heat flux is varied.

Effect of Copper Wire Placement Speed Analysis on Actuator Arm by Finite Element

2014 ◽  
Vol 931-932 ◽  
pp. 994-998
Author(s):  
Rangsan Wannapop ◽  
Thira Jearsiripongkul ◽  
Thawatchai Boonluang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Program ◽  
3D Model ◽  
Copper Wire ◽  
Dynamic Finite Element ◽  
Effect Of Copper ◽  
Explicit Dynamic ◽  
Automatic Loading ◽  
Element Method

This research represents a design and analysis of Automatic loading copper wire machine for the actuator arm (ALCM). The process of copper wire placement on a single actuator arm type compensates human workers. In this research, copper wire placement set is made as a 3D model by computer program before undergoes arrangement analysis via explicit dynamic finite element method to study a suitable speed for copper wire placing. It is considered by characteristics of copper wire after placed and failures occurred during the process that will define suitable speed of motor rotation. The suitable speed is corresponding to copper wire characteristic as preferred, prevent copper wire fracture and time reduction compare to human work.

DYNAMIC SIMULATION OF THE TAILING PROCESS IN HOT FINISHING MILL

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5661-5666
Author(s):  
SHINIL KIM ◽  
CHENG LU ◽  
XIAOZHONG DU ◽  
ANH KIET TIEU
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tensile Stress ◽  
Deformation Behavior ◽  
Speed Ratio ◽  
Roll Speed ◽  
Dynamic Finite Element ◽  
Finishing Mill ◽  
Explicit Dynamic ◽  
Method Model

In this paper an explicit dynamic finite element method model has been developed to investigate the strip deformation behavior between two adjacent stands in hot finishing mill. The effect of the roll speed ratio of second stand to first stand on tension and the tailing behavior of the strip has been discussed in details. It has been found that the strip accumulation occurs if the roll speed ratio is small. The tensile stress increases with the roll speed ratio. During the tailing process the accumulated strip caused by the small roll speed ratios knocks onto the roll, while the swing of the strip tail occurs for the large roll speed ratios and it strikes the roll as well. Both tailing phenomena will result in the strip tail pincher or roll damage in the real operation.

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