Parametric study of resilient response of tracks with a sub-ballast layer

1999 ◽  
Vol 36 (6) ◽  
pp. 1137-1150 ◽  
Author(s):  
J T Shahu ◽  
NSV Kameswara Rao ◽  
Yudhbir
Keyword(s):  
Parametric Study ◽  
Rational Design ◽  
Numerical Models ◽  
Three Dimensional ◽  
Element Model ◽  
Test Results ◽  
Linear Elastic ◽  
Beam Elements ◽  
Track Parameter ◽  
Resilient Response

Formulation of a rational design methodology for laying or upgrading tracks for heavier and faster trains requires investigation of the effect of various track parameters on overall track responses. For this purpose, a three-dimensional linear elastic finite element model, 3D20N, is developed that uses 20-noded brick elements and 16-noded surface elements and models rails as one-dimensional beam elements. Modelling details related to rail elements enable this model to predict the track responses accurately. Assessment of predictive capabilities of the model has been carried out by detailed comparisons with other numerical models and measured field test results. A detailed parametric study of the track responses was carried out using this model for a typical track with a sub-ballast layer and by adopting a practical range of track variables. Subgrade modulus was found to be the most influential track parameter on the overall track responses. The next most important track parameters were depth of sub-ballast, rail moment of inertia, and tie spacing. Practical implications of predicted parametric trends are discussed.

scholarly journals Offshore anchor piles under mooring forces: numerical modeling

2013 ◽  
Vol 50 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Mohamed I. Ramadan ◽  
Stephen D. Butt ◽  
R. Popescu
Keyword(s):  
Parametric Study ◽  
Three Dimensional ◽  
Element Model ◽  
Model Parameters ◽  
Test Results ◽  
Dense Sand ◽  
Centrifuge Tests ◽  
Wide Range ◽  
Inclination Angles ◽  
Mooring Forces

A parametric study was carried out to study the behavior of offshore anchor piles under mooring forces in dense sand using a three dimensional (3-D) finite element model (FEM). The Mohr–Coulomb plastic model has been used to model the soil, and has been calibrated based on the centrifuge tests discussed in a Ph.D. thesis (published by Ramadan in 2011). The selection of model parameters and comparison of calibrated results with the centrifuge test results are discussed. In the parametric study, different pile lengths and diameters were considered to have different pile–soil rigidities. The pile was loaded at different load inclination angles to examine a wide range of loading conditions. From the current parametric study, design methods and design recommendations are given to help in improving the design of offshore anchor piles under monotonic mooring forces.

scholarly journals Membrane analogy for multi-material bars under torsion

2019 ◽  
Vol 475 (2225) ◽  
pp. 20190124 ◽  
Author(s):  
Laura Galuppi ◽  
Gianni Royer-Carfagni
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Problem ◽  
Two Dimensional ◽  
Torsion Problem ◽  
Linear Elastic ◽  
Physical Apparatus

Prandtl's membrane analogy for the torsion problem of prismatic homogeneous bars is extended to multi-material cross sections. The linear elastic problem is governed by the same equations describing the deformation of an inflated membrane, differently tensioned in regions that correspond to the domains hosting different materials in the bar cross section, in a way proportional to the inverse of the material shear modulus. Multi-connected cross sections correspond to materials with vanishing stiffness inside the holes, implying infinite tension in the corresponding portions of the membrane. To define the interface constrains that allow to apply such a state of prestress to the membrane, a physical apparatus is proposed, which can be numerically modelled with a two-dimensional mesh implementable in commercial finite-element model codes. This approach presents noteworthy advantages with respect to the three-dimensional modelling of the twisted bar.

scholarly journals Experimental Study on a New Reinforcement Method for Multilayer Industrial Building’s Vibration

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Kaizhong Xie ◽  
Hongwei Wang ◽  
Jianxi Zhou ◽  
Xiao Luo ◽  
Miao Yue
Keyword(s):  
Natural Frequency ◽  
Three Dimensional ◽  
Element Model ◽  
Industrial Building ◽  
Test Results ◽  
Dimensional Finite Element ◽  
Vibration Experiment ◽  
Length Direction ◽  
Strength And Stiffness ◽  
Three Dimensional Finite Element

In order to study a new reinforcement method for multilayer (4 layers) industrial building’s vibration, firstly, a new reinforcement method using a short-pier shear wall was put forward. Secondly, an engineering example of a multilayer industrial building with abnormal vibration was introduced. A three-dimensional finite element model of multilayer industrial building was established, and field vibration test was carried out. Test results showed that abnormal vibration of industrial building was caused by resonance between machines and multilayer industrial building. Finally, multilayer industrial building was reinforced by a new reinforcement method, and vibration experiment was carried out after reinforcement. The results show that the new reinforcement method has a good reinforcement effect. Strength and stiffness of multilayer industrial building were obviously improved, and natural frequency of industrial building in the length direction increased from 2.45 Hz to 5.87 Hz, natural frequency of industrial building in the width direction increased from 2.94 Hz to 7.83 Hz, frequencies of machines and frequencies of multilayer industrial building were not in resonance range, acceleration and velocity vibration characteristics of multilayer industrial building were improved, which can provide reference for the reinforcement of multilayer industrial building with a similar structural configuration.

NONLINEAR IMPACT DYNAMIC ANALYSIS AND COMPARISON WITH EXPERIMENTAL DATA FOR THE SKID GEAR

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1403-1408 ◽  
Author(s):  
DONG-HYUN KIM ◽  
YU-SUNG KIM
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Landing Gear ◽  
Gear System ◽  
Dynamic Responses ◽  
Test Results ◽  
Dimensional Finite Element ◽  
Nonlinear Transient ◽  
Skid Landing Gear ◽  
Three Dimensional Finite Element

In this study, nonlinear crash analyses have been conducted for the skid landing gear of helicopter. The realistic configuration of skid landing gear system is considered. Detailed three-dimensional finite element model with variable thickness and material nonlinearity is constructed for required impact design conditions. Advanced computational approach is used to conduct nonlinear transient impact dynamic analyses for different collision models. Characteristics of impact dynamic responses due to the ground crash are practically investigated in detail. It is also shown that the exact consideration of friction effect is very important to accurately predict the crash behavior of the skid type landing gear system. Finally, two typical landing conditions are analyzed and correlated with drop test results.

Theoretical and Experimental Research on Joint Slippage Effects of Lattice Angle Steel Tower

2013 ◽  
Vol 477-478 ◽  
pp. 660-665
Author(s):  
Zhang Qi Wang ◽  
Ze Ming Song ◽  
Wen Qiang Jiang
Keyword(s):  
Axial Force ◽  
Numerical Models ◽  
Element Model ◽  
Test Results ◽  
Bolted Joint ◽  
Transmission Tower ◽  
Hybrid Finite Element ◽  
Lattice Tower ◽  
Angle Steel ◽  
Bolt Diameter

In lattice angle steel transmission tower, as the bolt diameter is small and member connection is relatively thin, lower clamping force is commonly used in bolted joint. It is common in lattice tower during full tower tests, joint slippage occur even under design load. However, traditionally trussed beam hybrid finite element model without explicitly considering slippage effects has been widely used in the analysis of the tower. In this paper, the HD-1 tower was experimentally studied under various static load cases, and several numerical models with including joint eccentricity and slippage are established. After comparing the theoretical analysis results and the experimental results, the following conclusions are presented: joint eccentricity almost has not effects on leg member axial force; Among all the studied load cases, joint slippage effects the leg member force most under torsional condition than the other load conditions; Numerical model with including joint slippage effects yield much better axial force results in leg member compared with experimental test results.

Damage Analysis Model for RC Members Based on Level of Material

2010 ◽  
Vol 163-167 ◽  
pp. 1262-1267
Author(s):  
Zuo Hua Li ◽  
Jun Teng ◽  
Xue Feng He
Keyword(s):  
Statistical Analysis ◽  
Damage Index ◽  
Three Dimensional ◽  
Element Model ◽  
Damage Analysis ◽  
Analysis Model ◽  
Damage Behavior ◽  
Beam Elements ◽  
Column Element ◽  
Numerical Strategy

This paper presents a numerical strategy to model nonlinear damage behavior of RC members based on level of material. The first part of the paper presents a numerical model of the RC member based on the Timoshenko multifiber beam elements and non-linear damage constitutive laws for concrete, and the effective three dimensional fiber beam-column element model is developed for the nonlinear damage analysis of RC members with VUEL subroutine based on ABAQUS/Explicit platform. In the second part, a nonlinear damage analysis for RC members is established by analyzing the sections of fiber beam column elements, and the member damage index through statistical analysis of concrete fibers damage is defined in the extreme section of beam elements, which can describe the nonlinear damage behavior of RC members under any loadings. Accuracy of the model is identified preliminarily by comparing with the analysis results of solid elements, the results shows that it seems now possible to use this approach to investigate numerically the nonlinear damage behavior of RC members based on level of material.

scholarly journals Finite Element Modeling and Parametric Study on Floor Steel Beam Concrete Slab System in Non-Composite Action.

2018 ◽  
Vol 24 (7) ◽  
pp. 95
Author(s):  
Salah R. Al-Zaidee ◽  
Ehab Ghazi Al-Hasany
Keyword(s):  
Finite Element ◽  
Friction Force ◽  
Parametric Study ◽  
Numerical Models ◽  
Concrete Slab ◽  
Linear Regression Analysis ◽  
Element Model ◽  
Steel Beam ◽  
Composite Action ◽  
Shear Connectors

This study aims to show, the strength of steel beam-concrete slab system without using shear connectors (known as a non-composite action), where the effect of the friction force between the concrete slab and the steel beam has been investigated, by using finite element simulation. The proposed finite element model has been verified based on comparison with an experimental work. Then, the model was adopted to study the system strength with a different steel beam and concrete slab profile. ABAQUS has been adopted in the preparation of all numerical models for this study. After validation of the numerical models, a parametric study was conducted, with linear and non-linear Regression analysis. An equation regarding the concrete slab-steel beam system strength in non-composite action has been pointed out. Where the actual strength of the beam without using shear connectors has been located in between the full composite action and non-composite action. However, partial-composite action has been noted, due to the effectiveness of friction force which makes the beam behave as composite before the slip occurs.  

A Static and Dynamic Model of Geared Transmissions by Combining Substructures and Elastic Foundations—Applications to Thin-Rimmed Gears

2006 ◽  
Vol 129 (2) ◽  
pp. 184-194 ◽  
Author(s):  
M. N. Bettaïeb ◽  
P. Velex ◽  
M. Ajmi
Keyword(s):  
Finite Element ◽  
Contact Stiffness ◽  
Equations Of Motion ◽  
Hybrid Approach ◽  
Three Dimensional ◽  
Element Model ◽  
3D Finite Element ◽  
Elastic Foundations ◽  
Beam Elements ◽  
Set Up

The present work is aimed at predicting the static and dynamic behavior of geared transmissions comprising flexible components. The proposed model adopts a hybrid approach, combining classical beam elements, elastic foundations for the simulation of tooth contacts, and substructures derived from three-dimensional (3D) finite element grids for thin-rimmed gears and their supporting shafts. The pinion shaft and body are modeled via beam elements which simulate bending, torsion and traction. Tooth contact deflections are described using time-varying elastic foundations (Pasternak foundations) connected by independent contact stiffness. In order to account for thin-rimmed gears, a 3D finite element model of the gear (excluding teeth) is set up and a pseudo-modal reduction technique is used prior to solving the equations of motion. Depending on the gear structure, the results reveal a potentially significant influence of thin rims on both quasi-static and dynamic tooth loading.

A Parametric Study for the Seismic Response Analysis of a Nuclear Reactor Building by Using a Three-Dimensional Finite Element Model

2016 ◽  
Author(s):  
Byunghyun Choi ◽  
Akemi Nishida ◽  
Norihiro Nakajima
Keyword(s):  
Finite Element ◽  
Research And Development ◽  
Finite Element Model ◽  
Seismic Response ◽  
Parametric Study ◽  
Three Dimensional ◽  
Element Model ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Uncertainty Parameters

Research and development of three-dimensional vibration simulation technologies for nuclear facilities is one mission of the Center for Computational Science and e-Systems of the Japan Atomic Energy Agency (JAEA). A seismic intensity of upper 5 was observed in the area of High-Temperature Engineering Test Reactor (HTTR) at the Oarai Research and Development Center of JAEA during the 2011 Tohoku earthquake. In this paper, we report a seismic response analysis of this earthquake using three-dimensional models of the HTTR building. We performed a parametric study by using uncertainty parameters. Furthermore, we examined the variation in the response result for the uncertainty parameters to create a valid 3D finite element model.

Analytical Simulations of the Steel-Laminated Elastomeric Bridge Bearing

2014 ◽  
Vol 30 (4) ◽  
pp. 373-382 ◽  
Author(s):  
R.-Z. Wang ◽  
S.-K. Chen ◽  
K.-Y. Liu ◽  
C.-Y. Wang ◽  
K.-C. Chang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Fem Analysis ◽  
Material Model ◽  
Element Model ◽  
Test Results ◽  
3D Fem ◽  
Contact Algorithm ◽  
Elastomeric Bearing ◽  
Nonlinear Responses ◽  
Bridge Bearing

AbstractIn this paper, analytical simulations of the steel-laminated elastomeric bearing (SLEB) using a three-dimensional (3D) finite element model incorporating material, geometric nonlinearities, and a frictional contact algorithm in LS-DYNA code is conducted. In order to simulate the nonlinear responses of the elastomeric bearing under the compression and shear, a hyperviscoelastic rubber model such as The MAT_77_H (MAT_HYPERVISCOELASTIC_RUBBER) in LS- DYNA code is adopted. Based on the proposed material model for the SLEB, the interaction effects of the SLEB under compression, bending, and torsion are analyzed. Analytical results are compared with the test results of the SLEBs. A set of material parameters is proposed for 3D FEM analysis of SLEBs. The proposed material model demonstrates its accuracy.

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