scholarly journals Study on the System Reliability of Steel-Concrete Composite Beam Cable-stayed Bridge

2016 ◽  
Vol 10 (1) ◽  
pp. 418-432 ◽  
Author(s):  
Buyu Jia ◽  
Xiaolin Yu ◽  
Quansheng Yan ◽  
Zhen Yang
Keyword(s):  
Mechanical Behavior ◽  
System Reliability ◽  
Composite Beam ◽  
Degrees Of Freedom ◽  
Failure Modes ◽  
Limit State ◽  
Element Model ◽  
Differential Method ◽  
Component Reliability ◽  
Cable Stayed Bridge

Steel-concrete composite beam cable-stayed bridge is a complicated system consisting of a composite beam, tower, and stayed cables. And the composite beam is composed of a steel beam, bridge deck and connectors, which has a different mechanical behavior from the general beam structure. In a word, the steel-concrete composite beam cable-stayed bridge is characterized by specific mechanical behavior and has many influencing factors. Thus, its safety analysis often cannot be easily implemented. This paper aims to study the component reliability of the steel-concrete composite beam based on the stochastic finite element method (SFEM) and the recognition of main failure modes in the system reliability of the cable-stayed bridge. For the component reliability of the steel-concrete composite beam, a nonlinear element model with 10 degrees of freedom (DOF) is adopted, which can consider the particular longitudinal slip effect between the steel and concrete. And the direct differential method (DDM) is used to deduce the response gradient of the element model. Meanwhile, the tower and the composite beam are considered as beam-column members to establish their limit state functions in the form of interaction equations. For the recognition of main failure modes in the system reliability, this paper proposes the concept of uniformity of the reliability index and the refinement strategy to improve theβ-unzipping method, which can identify the main failure modes or neglect the unnecessary non-main failure modes. Finally, a certain steel-concrete composite beam cable-stayed bridge is used to verify the effectiveness of the proposed method.

A FEA Simulation Model for Thin-Walled C-Section Composite Beam Assembling With R-Angle Deviation

2014 ◽  
Author(s):  
Hua Wang ◽  
Suo Si
Keyword(s):  
Numerical Model ◽  
Composite Beam ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Element Model ◽  
Load Level ◽  
Compression Tests ◽  
Accurate Analysis ◽  
Angle Deviation ◽  
Thin Walled

There are unavoidable deviations, such as shrinkage and distortions, in the composite detail parts production due to the complexity of composites fabrication. Interests in the assembly analysis of composite beams have led to a need for more accurate analysis especially in the case of fabrication deviations. This work proposes a numerical finite element model of thin-walled C-section composite beam with R-angle deviation for assembling. The rule of Hashin failure combined with cohesive element is applied to study the mechanical performance of the fiber and matrix (implemented as user subroutine UMAT in ABAQUS) while positioning and clamping. Tension and compression tests are carried out based on available standards to determine the C-section beam behavior under load. The testing data validates the proposed numerical model. The numerical model captures the experimentally obtained results with minimal error, and predicts the failure modes successfully. The proposed model allows to determine accurately the first failure location and the associated load level. It will enhance the understanding of the composite components pre-loading analysis, and help systematically improving the composites assembling efficiency in civil aircraft industry.

Reliability Model for Complex Mechanical Component Design

2013 ◽  
Vol 365-366 ◽  
pp. 28-31
Author(s):  
Li Yang Xie ◽  
Wen Xue Qian ◽  
Ning Xiang Wu
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
Statistical Dependence ◽  
Series System ◽  
Reliability Model ◽  
Component Reliability ◽  
Damage Site ◽  
Mechanical Component ◽  
Component Design ◽  
Element Failure

Taking into account the uncertainty in material property and component quality, a complex mechanical component such as a gear should be treated as a series system instead of a component when evaluating its reliability, since there exist many sites of equal likelihood to fail. Besides, conventional system reliability model is not applicable to such a system because of the statistical dependence among the failures of the every element (damage site). The present paper presents a model to estimate complex mechanical component reliability by incorporating order statistic of element strength into load-strength interference analysis, which can deal with multiple failure mechanisms, reflect statistical dependence among element failure events and that among different failure modes.

Experimental Study on Mechanical Behavior of Serving Prestressed Concrete Poles

2011 ◽  
Vol 368-373 ◽  
pp. 1617-1620 ◽  
Author(s):  
Kai Quan Xia ◽  
Xiang Gang Zhang ◽  
Zong Ping Chen ◽  
Jiang Mei Wang
Keyword(s):  
Mechanical Behavior ◽  
Prestressed Concrete ◽  
Failure Modes ◽  
Ultimate Load ◽  
Design Method ◽  
Limit State ◽  
Safety Performance ◽  
Reinforced Beams ◽  
Loading Tests ◽  
Bending Loading

In order to assess accurately safety performance of prestressed concrete poles servicing 30 years, bending loading tests are carried out on 3 samples extracted randomly, these ones are studied on the mechanical behavior and failure mechanism, failure modes are revealed, and important experimental data including cracking load, the ultimate load of normal use, the ultimate load of carrying capacity is obtained. Furthermore, based on measured test data, the curves of load-crack width and moment-deflection are made among the whole force process. The results show that failure modes of specimens are similar to one of “rare-reinforced beams”. Moreover, based on design method of serviceability limit state, the average security surplus coefficient is 1.2 before collapse damage.

Innovative Applications of Steel Fibres in Concrete Flange of Composite Beam Subjected to Combined Negative Bending and High Axial Tension

2015 ◽  
Vol 1129 ◽  
pp. 367-374
Author(s):  
Mahesan Bavan ◽  
Shahrizan bin Baharom ◽  
Siti Aminah Osman
Keyword(s):  
Composite Beam ◽  
Failure Modes ◽  
Limit State ◽  
Experimental Studies ◽  
Plain Concrete ◽  
Ultimate Limit State ◽  
Steel Fibres ◽  
Axial Tension ◽  
Negative Bending ◽  
Ultimate Limit

The steel-concrete composite beam has become very popular these days and deterioration of the composite beam and its ultimate limit state are often reported in the subjection of combined negative bending and axial tension. Due to the presence of high axial loads, it was given a guideline in a previous research study by experimental investigation such that the failure modes were reinforcement fracture and shear connection failure in limiting the ultimate limit state of the composite beam subjected to combined negative bending and high axial tension rather than concrete failure. Thus, it is important to study in order to implement the strengthening methods with innovative material applications to overcome this problem. It was assumed that the application of steel fibres in the concrete flange will be an excellent contender owing to its in-service and mechanical properties, which is the hypothesis of this research. In order to evaluate this concept, the finite element (FE) models of a composite beam subjected to negative bending and high axial tension, and steel fibre reinforced concrete (SFRC) slab were developed with non-linear material components and validated with relevant experimental studies. Consequently, the plain concrete flange of composite beam was replaced by SFRC flange and studied the failure behaviour of the composite beam subjected to combined negative bending and high axial tension. It was predicted that an improvement in the ultimate limit state and in initial cracking load due to the postponing the failure modes, which are extensively discussed and suggested as it will be a strengthening method of the concrete flange on the composite beam in such cases.

Research on Horizontal Scheme for Multi-Pylon Cable-Stayed Bridge

2012 ◽  
Vol 446-449 ◽  
pp. 1217-1220
Author(s):  
Yue Qiang ◽  
Li Li ◽  
Peng Cheng Li ◽  
He Jian
Keyword(s):  
Comparative Analysis ◽  
Mechanical Behavior ◽  
Element Model ◽  
Model Analysis ◽  
Simplified Model ◽  
Longitudinal Displacement ◽  
Cable Stayed Bridge ◽  
Cable Force ◽  
Midspan Deflection

Longitudinal assembled stiffness is the biggest problem for multi-pylon cable-stayed bridge. The longitudinal displacement and midspan deflection could be effectively controlled by setting horizontal cable at the top of pylon of multi-pylon cable-stayed bridge. This paper obtains the area and the cable force change formula of the horizontal cable through simplified model analysis of the mechanical behavior of setting horizontal cable at the top of pylon. The comparative analysis is performed by application of finie element model to discuss the effect of setting horizontal cable at the top of pylon of multi-pylon cable-stayed bridge.

scholarly journals Probabilistic Approach to System Reliability of Mechanism with Correlated Failure Models

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Xianzhen Huang ◽  
Yimin Zhang
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
Failure Modes ◽  
Limit State ◽  
Probabilistic Approach ◽  
Upper And Lower Bounds ◽  
State Function ◽  
System Reliability Analysis ◽  
Kinematic Performance ◽  
Planar Linkages

In this paper, based on the kinematic accuracy theory and matrix-based system reliability analysis method, a practical method for system reliability analysis of the kinematic performance of planar linkages with correlated failure modes is proposed. The Taylor series expansion is utilized to derive a general expression of the kinematic performance errors caused by random variables. A proper limit state function (performance function) for reliability analysis of the kinematic performance of planar linkages is established. Through the reliability theory and the linear programming method the upper and lower bounds of the system reliability of planar linkages are provided. In the course of system reliability analysis, the correlation of different failure modes is considered. Finally, the practicality, efficiency, and accuracy of the proposed method are shown by a numerical example.

Time-Dependent System Reliability Analysis With Second-Order Reliability Method

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Hao Wu ◽  
Zhangli Hu ◽  
Xiaoping Du
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
Limit State ◽  
Second Order ◽  
Time Dependent ◽  
Component Reliability ◽  
Reliability Method ◽  
Series Systems ◽  
State Functions ◽  
Time Dependent System

Abstract System reliability is quantified by the probability that a system performs its intended function in a period of time without failures. System reliability can be predicted if all the limit-state functions of the components of the system are available, and such a prediction is usually time consuming. This work develops a time-dependent system reliability method that is extended from the component time-dependent reliability method using the envelope method and second-order reliability method. The proposed method is efficient and is intended for series systems with limit-state functions whose input variables include random variables and time. The component reliability is estimated by the second-order component reliability method with an improve envelope approach, which produces a component reliability index. The covariance between component responses is estimated with the first-order approximations, which are available from the second-order approximations of the component reliability analysis. Then, the joint distribution of all the component responses is approximated by a multivariate normal distribution with its mean vector being component reliability indexes and covariance being those between component responses. The proposed method is demonstrated and evaluated by three examples.

Time-Dependent System Reliability Analysis With Second Order Reliability Method

2020 ◽  
Author(s):  
Hao Wu ◽  
Xiaoping Du
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
Limit State ◽  
Second Order ◽  
Time Dependent ◽  
Component Reliability ◽  
Reliability Method ◽  
Series Systems ◽  
State Functions ◽  
Time Dependent System

Abstract System reliability is quantified by the probability that a system performs its intended function in a period of time without failure. System reliability can be predicted if all the limit-state functions of the components of the system are available, and such a prediction is usually time consuming. This work develops a time-dependent system reliability method that is extended from the component time-dependent reliability method that uses the envelop method and second order reliability method. The proposed method is efficient and is intended for series systems with limit-state functions whose input variables include random variables and time. The component reliability is estimated by the existing second order component reliability method, which produces component reliability indexes. The covariance between components responses are estimated with the first order approximations, which are available from the second order approximations of the component reliability analysis. Then the joint probability of all the component responses is approximated by a multivariate normal distribution with its mean vector being component reliability indexes and covariance being those between component responses. The proposed method is demonstrated and evaluated by three examples.

Study on Space Nonlinear FE Model of Composite Beam Cable-Stayed Bridge with Three Towers

2011 ◽  
Vol 90-93 ◽  
pp. 975-978
Author(s):  
Feng Wang
Keyword(s):  
Composite Beam ◽  
Shell Element ◽  
Element Model ◽  
Internal Force ◽  
Fe Model ◽  
Beam Model ◽  
Single Beam ◽  
Cable Stayed Bridge ◽  
Double Beam ◽  
Nonlinear Finite Element Model

Taking Wuhan Erqi Yangtze River Bridge as an example, based on link element, shell element, and beam element, a double beam nonlinear finite element model is purposed using popular finite analyzing software ANSYS. The internal force and deformation characteristics of composite beam cable-stayed bridge with three towers is analyzed by double beam model, and compared to the single beam. The results show that the double beam nonlinear FE model, which have less freedom and conveniently calculate, can be used to well analyze the nonlinear of composite beam cable-stayed bridge with three towers.

System Reliability of Jack-Up Platforms Under Fatigue and Fracture Failures

2008 ◽  
Author(s):  
Naser Shabakhty
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
Limit State ◽  
Crack Size ◽  
System Failure ◽  
Structural Element ◽  
New Approach ◽  
Fatigue And Fracture ◽  
Fatigue Limit State ◽  
Jack Up

Jack-up is a rig for oil drilling and exploration in shallow water. The ability of movement from one location to another place, in addition to the possibility of lifting up the hull during operation, increase demand for the use of this platform in deeper water and harsher environments. Fatigue is the process of damage accumulation in material due to stress fluctuation caused by variation of loads in service time. The fatigue failure occurs when accumulated damage has exceeded a critical level. In practice, some uncertainties are included in loads and characteristics of capacity demand. It will be reasonable to take these uncertainties into account within reliability framework. Based on the crack propagation approach and fracture mechanics, a reliability of structural element under fatigue degradation can be estimated. However, the first failure of structural element under fatigue degradation may not cause system failure. This paper presents a new approach to estimate structural system reliability of jack-up platforms in combination of fatigue and fracture failure modes. The probability of failure of each component is firstly estimated using fatigue limit state and the subsequent failure probability is calculated extending fracture modes. In fracture mode, the crack size is required. In this paper a new approach based on Monte Carlo Simulation is presented to estimate the statistical crack size in accordance to the fatigue limit state. Important sequences of failure are then identified utilizing branch and bound technique and finally the system reliability through combination of important failure paths leading to system failure has been calculated. The advantage of this method is that the FORM or SORM technique can be applied to compute each failure path individually and finally determine system reliability based on combination of significant failure paths identified in branch and bound search technique. It is shown the system failure in this sequence has higher probability than the entirely first and second failure under fatigue failure modes.

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