scholarly journals Energy Response Analysis of Continuous Beam Bridges with Friction Pendulum Bearing by Multihazard Source Excitations

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Bing Li ◽  
Bin Wang ◽  
Shaohua Wang ◽  
Xiao Wu
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Structural Response ◽  
Analytical Modelling ◽  
Continuous Beam ◽  
Energy Response ◽  
Isolated Bridge ◽  
Friction Pendulum ◽  
Isolated Bridges ◽  
Isolation Period

Based on the principle of conservation of energy, analytical modelling of the energy response of continuous beam bridges with friction pendulum bearing (FPB) was carried out for foundation-induced vibrations. A three-dimensional finite element analysis of a multispan continuous concrete girder bridge with FPB was established using the nonlinear time-history method to verify the accuracy of analytical modelling. The influence of the friction coefficient and isolation period of the FPB on the energy response of isolated bridge was then investigated under multihazard source excitations (e.g., El Centro and Taft waves) with different dominant periods and durations. The variations of structural response energy, sliding displacement, energy dissipation ratio, and acceleration of the isolated bridges are plotted. The results of analytical modelling and finite element simulation show good agreement. In addition, there exist particular values of the friction coefficient and isolation period of FPB, for which the structural response energy of the isolated bridges attains the minimum value. The optimal parameters of FPB are greatly influenced by seismic waves, and the friction coefficient of FPB should be increased with the increase of seismic fortification intensity. In addition, the energy dissipation capacity of FPB used in isolated bridge is excellent.

scholarly journals A constant friction coefficient model for concave friction bearings

2020 ◽  
Vol 14 (1) ◽  
pp. 112-126
Author(s):  
Dao Dinh Nhan ◽  
Chung Bac Ai
Keyword(s):  
Friction Coefficient ◽  
Numerical Models ◽  
Structural Response ◽  
Time History ◽  
Friction Model ◽  
System Response ◽  
Isolation System ◽  
Constant Friction ◽  
Friction Pendulum ◽  
Friction Bearings

This paper develops a constant friction coefficient model that best represents a velocity-dependent friction model for predicting structural response of buildings isolated with concave friction bearings. To achieve this goal, the effect of friction model on structural response of three hypothetical isolated buildings with different number of stories subjected to different earthquake scenarios was numerically investigated. The structural numerical models of the isolated buildings were developed in OpenSees with superstructure is represented by a shear frame model and isolation system using single friction pendulum bearings is modeled by a 3-D friction pendulum bearing element which accepts different friction models. The numerical models were subjected to 30 pairs of ground motions, representing service earthquake level, design basic earthquake level and maximum considered earthquake level at a strong seismic activity area in the world. The investigation reveals that friction coefficient models significantly affect the structural response and there is no constant friction coefficient model that simultaneously best predicts isolation system response and superstructure response. The constant friction coefficient that best predicts isolation system response produces a large error on prediction of superstructure response and vice versa. Based on the numerical results, a constant friction coefficient model for different criteria was developed. Keywords: friction coefficient model; friction bearing; isolation system; earthquake response; time-history analysis.

Finite Element Formulations for Direction Optimized-Variable Curvature Friction Pendulum System

2007 ◽  
Author(s):  
C. S. Tsai ◽  
T. C. Chiang ◽  
Wen-Shin Chen
Keyword(s):  
Finite Element ◽  
Base Isolation ◽  
Concave Surface ◽  
Sliding Surface ◽  
Pendulum System ◽  
Variable Curvature ◽  
Friction Pendulum ◽  
Isolation Period ◽  
Finite Element Formulations ◽  
Friction Pendulum System

The base isolation technology has been recognized as a very effective tool for controlling the seismic response of a structure during earthquakes. However, it is suggested from recent studies that the earthquakes with long predominant periods results in significant seismic responses of the base isolated structure. In view of this, a new base isolator called the Directional Optimized-Variable Curvature Friction Pendulum System (DO-VCFPS) has been proposed in this study. The radii of the curvature of the trench concave surface and the spherical sliding surface are lengthened with increasing the sliding displacement. Therefore, the isolation period can be shifted further away from the predominant periods of ground motions. Furthermore, by using the series connection of a trench concave surface and a spherical sliding surface, the isolation period is a function of the angle between the directions of the resultant displacement. In order to prove the efficiency of the proposed device, the finite element formulations of the DOVCFPS have been derived in this study. The numerical results show that the combination of the advantages of the Variable Curvature Friction Pendulum System (VCFPS) and the Directional Optimization Friction Pendulum System (DO-FPS) can improve the disadvantages of a base isolated structure with fixed isolation period.

Influence of the contact with friction on the deformation behavior of advanced high strength steels in the Nakajima test

2021 ◽  
pp. 030932472110212
Author(s):  
Mohammad Mehdi Kasaei ◽  
Marta C Oliveira
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Contact Pressure ◽  
Deformation Behaviour ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Deformation Mechanics ◽  
Nakajima Test

This work presents a new understanding on the deformation mechanics involved in the Nakajima test, which is commonly used to determine the forming limit curve of sheet metals, and is focused on the interaction between the friction conditions and the deformation behaviour of a dual phase steel. The methodology is based on the finite element analysis of the Nakajima test, considering different values of the classic Coulomb friction coefficient, including a pressure-dependent model. The validity of the finite element model is examined through a comparison with experimental data. The results show that friction affects the location and strain path of the necking point by changing the strain rate distribution in the specimen. The strain localization alters the contact status from slip to stick at a portion of the contact area from the pole to the necking zone. This leads to the sharp increase of the strain rate at the necking point, as the punch rises further. The influence of the pressure-dependent friction coefficient on the deformation behaviour is very small, due to the uniform distribution of the contact pressure in the Nakajima test. Moreover, the low contact pressure range attained cannot properly replicate real contact condition in sheet metal forming processes of advanced high strength steels.

3D Coupled Thermomechanical Finite Element Analysis of Ultrasonic Consolidation

2007 ◽  
Vol 539-543 ◽  
pp. 2651-2656 ◽  
Author(s):  
C.J. Huang ◽  
E. Ghassemieh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Stress Field ◽  
Ultrasonic Wave ◽  
Ultrasonic Vibration ◽  
Softening Effect ◽  
Element Analysis ◽  
Consolidation Process ◽  
Ultrasonic Consolidation

A 3-D coupled temperature-displacement finite element analysis is performed to study an ultrasonic consolidation process. Results show that ultrasonic wave is effective in causing deformation in aluminum foils. Ultrasonic vibration leads to an oscillating stress field. The oscillation of stress in substrate lags behind the ultrasonic vibration by about 0.1 cycle of ultrasonic wave. The upper foil, which is in contact with the substrate, has the most severe deformation. The substrate undergoes little deformation. Apparent material softening by ultrasonic wave, which is of great concern for decades, is successfully simulated. The higher the friction coefficient, the more obvious the apparent material softening effect.

scholarly journals Relationship Between Rockwell C Hardness and Inelastic Material Constants

2002 ◽  
Vol 124 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Akihiko Hirano ◽  
Masao Sakane ◽  
Naomi Hamada
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Hardening ◽  
Yield Stress ◽  
Plastic Material ◽  
Stress And Strain ◽  
Material Constants ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Hardening Coefficient

This paper describes the relationship between Rockwell C hardness and elastic-plastic material constants by using finite element analyses. Finite element Rockwell C hardness analyses were carried out to study the effects of friction coefficient and elastic-plastic material constants on the hardness. The friction coefficient and Young’s modulus had no influence on the hardness but the inelastic materials constants, yield stress, and strain hardening coefficient and exponent, had a significant influence on the hardness. A new equation for predicting the hardness was proposed as a function of yield stress and strain hardening coefficient and exponent. The equation evaluated the hardness within a ±5% difference for all the finite element and experimental results. The critical thickness of specimen and critical distance from specimen edge in the hardness testing was also discussed in connection with JIS and ISO standards.

A Study on the Restrainer for Isolated Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 5208-5213
Author(s):  
Yong Feng Du ◽  
Xiao Yu Sun
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Nonlinear Characteristics ◽  
Isolation System ◽  
Finite Element Software ◽  
Continuous Beam Bridge ◽  
History Analysis ◽  
Isolated Bridge ◽  
Isolated Bridges ◽  
Beam Bridge

As a result of adopting isolated bearings, it is inevitable to increase the lateral displacement of the superstructure and the chance of girder falling. However, the shear keys that just satisfies the structural design is far from meeting the requirements of displacement of isolated bridge restrictions. On account of this, given the nonlinear characteristics of bearings and the restrainer, the authors make the study on the "damping rubber with coupling collar" restrainer, and then establish isolation system model of continuous beam bridge with finite element software named Midas. Meanwhile, the effect of the restrainer on the dynamic response of isolated bridges is presented by time-history analysis, which reveals the great value in the application of limiting displacement of isolated bridge.

Finite element formulation and shaking table tests of direction-optimized-friction-pendulum system

2008 ◽  
Vol 30 (9) ◽  
pp. 2321-2329 ◽  
Author(s):  
C.S. Tsai ◽  
Po-Ching Lu ◽  
Wen-Shin Chen ◽  
Tsu-Cheng Chiang ◽  
Chen-Tsung Yang ◽  
...  
Keyword(s):  
Finite Element ◽  
Shaking Table ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Shaking Table Tests ◽  
Pendulum System ◽  
Friction Pendulum ◽  
Friction Pendulum System

scholarly journals Design and Structural Analysis of a SWATH type vessel using the Finite Element Method and its response to Slamming events

2020 ◽  
Vol 14 (27) ◽  
pp. 55-66
Author(s):  
Hugo Leonardo Murcia Gallo ◽  
Richard Lionel Luco Salman ◽  
David Ignacio Fuentes Montaña
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Speed ◽  
Load Condition ◽  
Structural Response ◽  
Water Area ◽  
The Finite Element Method ◽  
Short Period ◽  
Classification Society ◽  
Element Method

The main objective of this study is to analyze the structural response of a boat during a slamming event using the Finite Element Method in a Small Water Area Twin Hull (SWATH) type boat.  In the mentioned load condition, the acceptance criteria established by a classification society must be fulfilled, taking into account the areas where this event affects the structure such as the junction deck, the pontoons and other structural members established by the standard, all this generated by the high pressure loads in the ship's structure in a very short period of time being an element of study in this type of vessels, as long as they are within the range of high speed vessels. Among the main results of this study were the deformations and stresses in the structure obtained under the reference parameters of the classification society.

Creative Design-by-Analysis Solutions Applied to High-Temperature Components

1993 ◽  
Vol 115 (3) ◽  
pp. 221-227
Author(s):  
A. K. Dhalla
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Detailed Analysis ◽  
Structural Response ◽  
Cost Effective ◽  
Element Analysis ◽  
Finite Element Software ◽  
Division 1 ◽  
High Temperature Components ◽  
Elevated Temperature Design

Elevated temperature design has evolved over the last two decades from design-by-formula philosophy of the ASME Boiler and Pressure Vessel Code, Sections I and VIII (Division 1), to the design-by-analysis philosophy of Section III, Code Case N-47. The benefits of design-by-analysis procedures, which were developed under a US-DOE-sponsored high-temperature structural design (HTSD) program, are illustrated in the paper through five design examples taken from two U.S. liquid metal reactor (LMR) plants. Emphasis in the paper is placed upon the use of a detailed, nonlinear finite element analysis method to understand the structural response and to suggest design optimization so as to comply with Code Case N-47 criteria. A detailed analysis is cost-effective, if selectively used, to qualify an LMR component for service when long-lead-time structural forgings, procured based upon simplified preliminary analysis, do not meet the design criteria, or the operational loads are increased after the components have been fabricated. In the future, the overall costs of a detailed analysis will be reduced even further with the availability of finite element software used on workstations or PCs.

Sign in / Sign up

Export Citation Format

Share Document