Mechanical Behavior of Composite Girder with Perfobond Shear Connector under Hogging Moment

2012 ◽  
Vol 446-449 ◽  
pp. 1046-1053
Author(s):  
Jun He ◽  
Yu Qing Liu ◽  
Chen Zhao ◽  
Ai Rong Chen ◽  
Teruhiko Yoda
Keyword(s):  
Mechanical Behavior ◽  
Concrete Slab ◽  
Limit State ◽  
Experimental Studies ◽  
Scale Model ◽  
Flexural Stiffness ◽  
Shear Connector ◽  
Inelastic Behavior ◽  
Stiffness Reduction ◽  
Composite Girders

The mechanical behavior of the support regions for continuous composite girders with tensile stresses in the concrete slab and compressive stresses in the lower steel profile becomes strongly nonlinear under negative bending moments. A static test on four half-scale model of a steel and concrete composite girders with different shear connectors including studs and PBL under hogging moments was conducted and observed to evaluate the influence of shear connector on inelastic behavior such as flexural stiffness reduction, crack initiation and development in concrete slab. From the test results, the flexural stiffness and loading capacity of the composite girders were improved by PBL shear connector. Higher initial cracking load and crack resistance stiffness of composite girders with PBL shear connector under serviceability limit state was obtained during crack development process. The test specimen could be assumed as full composite section until the ultimate state from load-slip relationship of shear connector. Analytical and experimental studies can serve as a basis for continuous composite bridges design.

Response of fire exposed composite girders under dominant flexural and shear loading

2018 ◽  
Vol 9 (2) ◽  
pp. 108-125 ◽  
Author(s):  
Mohannad Naser ◽  
Venkatesh Kodur
Keyword(s):  
Elevated Temperatures ◽  
Concrete Slab ◽  
Limit State ◽  
Shear Loading ◽  
Critical Parameters ◽  
Buckling Mode ◽  
Steel Girder ◽  
Content Type ◽  
Numerical Studies ◽  
Composite Girders

Purpose This paper aims to present results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading. A finite element-based numerical model was developed to trace the thermal and structural response of composite girders subjected to simultaneous structural loading and fire exposure. This model accounts for various critical parameters including material and geometrical nonlinearities, property degradation at elevated temperatures, shear effects, composite interaction between concrete slab and steel girder, as well as temperature-induced local buckling. To generate test data for validation of the model, three composite girders, each comprising of hot-rolled (standard) steel girder underneath a concrete slab, were tested under simultaneous fire and gravity loading. Design/methodology/approach The validated model was then applied to investigate the effect of initial geometric imperfections, load level, thickness of slab and stiffness of shear stud on fire response of composite girders. Findings Results from experimental and numerical analysis indicate that the composite girder subjected to flexural loading experience failure through flexural yielding mode, while the girders under shear loading fail through in shear web buckling mode. Further, results from parametric studies clearly infer that shear limit state can govern the response of fire exposed composite girders under certain loading configuration and fire scenario. Originality/value This paper presents results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading.

scholarly journals Experimental Investigation of the Mechanical Behavior of NC Linings in consideration of Voids and Lining Thinning

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Zude Ding ◽  
Jincheng Wen ◽  
Xiafei Ji ◽  
Zhihua Ren ◽  
Sen Zhang
Keyword(s):  
Mechanical Behavior ◽  
Local Deformation ◽  
Scale Model ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Normal Concrete ◽  
Failure Characteristics ◽  
Defect Position ◽  
Deformation Properties ◽  
Combined Defects

The presence of voids or lining thinning directly affects the mechanical behavior of linings, and these defects threaten the safety of tunnel operation. In this study, a series of 1/5-scale model tests was used to investigate the mechanical behavior of normal concrete (NC) linings in consideration of voids and combined defects. Test results showed that the void and combined defects substantially reduced the load-bearing capacity and deformation properties of the linings. The inelastic mechanical behavior of the linings was also significantly affected by the defects. The effects of lining defects located at the spandrel were slightly weaker than those of lining defects located at the crown. As the void size or degree of combined defects increased, the tensile strain at the location of the lining defects also increased. Therefore, the defect position of the linings was easily damaged. The defects considerably reduced the overall deformation of the linings but increased the local deformation. The distribution of lining cracks was concentrated at the defect position. In addition, different failure characteristics of the lining were observed due to the differences in defects.

Thermal and mechanical improvement of the air supply system of a turbocharged piston engine

2021 ◽  
Vol 14 (2) ◽  
pp. 108-114
Author(s):  
Y. M. Brodov ◽  
L. V. Plotnikov ◽  
K. O. Desyatov
Keyword(s):  
Heat Transfer ◽  
Experimental Studies ◽  
Local Heat Transfer ◽  
Supply System ◽  
Scale Model ◽  
Piston Engine ◽  
Intake System ◽  
Gas Dynamic ◽  
Air Supply ◽  
Air Flows

A method of thermomechanical improvement of pulsating air flows in the intake system of a turbocharged piston engine is described. The main objective of this study is to develop a method for suppressing the rate of heat transfer to improve the reliability of a piston turbocharged engine. A brief review of the literature on improving the reliability of piston engines is given. Scientific and technical results were obtained on the basis of experimental studies on a full-scale model of a piston engine. The hot-wire anemometer method was used to obtain gas-dynamic and heatexchange characteristics of gas flows. Laboratory stands and instrumentation facilities are described in the article. The data on gas dynamics and heat exchange of stationary and pulsating air flows in gas-dynamic systems of various configurations as applied to the air supply system of a turbocharged piston engine are presented. A method of thermomechanical improvement of flows in the intake system of an engine based on a honeycomb is proposed in order to stabilize the pulsating flow and suppress the intensity of heat transfer. Data were obtained on the air flow rate and the local heat transfer coefficient both in the exhaust duct of the turbocharger compressor (i.e., without a piston engine) and in the intake system of a supercharged engine. A comparative analysis of the data has been carried out. It was found that the installation of a leveling grid in the exhaust channel of a turbocharger leads to an intensification of heat transfer by an average of 9%. It was found that the presence of a leveling grid in the intake system of a piston engine causes the suppression of heat transfer within 15% in comparison with the baseline values. It is shown that the use of a modernized intake system in a diesel engine increases its probability of failure-free operation by 0.8%. The data obtained can be extended to other types and designs of air supply systems for heat engines.

scholarly journals Low-rise structures in reinforced concrete: approximation of material nonlinearity for global stability analysis

2018 ◽  
Vol 11 (1) ◽  
pp. 1-25
Author(s):  
L. M. MOREIRA ◽  
C. H. MARTINS
Keyword(s):  
Global Stability ◽  
Iterative Process ◽  
Global Analysis ◽  
Second Order ◽  
Material Nonlinearity ◽  
Flexural Stiffness ◽  
Analysis Model ◽  
Structural Element ◽  
Global Stability Analysis ◽  
Stiffness Reduction

Abstract In the analysis of the second-order global effects, the material nonlinearity (NLF) can be considered in an approximate way, defining for the set of each structural element a mean flexural stiffness. However, there is less research concerning low-rise buildings in the analysis of global stability in contrast to high buildings, because these have a greater sensitivity to this phenomenon and they are more studied. In this way, the paper objective is to determine the flexural stiffness values, of beams and columns, for buildings with less than four floors, to approximate consideration of the NLF in the global analysis. The idealized examples to buildings with 1, 2 and 3 floors, being simulated through the software CAD/TQS and an analysis model based in an iterative process. The simulations results defined the stiffness values of the set of beams and columns in each example, followed by a statistical analysis to define general values of application in the buildings. Finally, a proposal is suggested of stiffness reduction coefficients for beams and columns to be adopted in the approximation the NLF (EIsec = αv/p ∙ Eci Ic), as follows: buildings with 1 floor (αv = 0,17 and αp = 0,66), buildings with 2 floors (αv = 0,15 and αv = 0,71) and buildings with 3 floors (αv = 0,14 and αv = 0,72). The results obtained can be used for the analysis of low-rise structures to consider the second order global effects with more safely.

Investigation on Mechanical Properties of Fibreglass Reinforced Flexible Pipes Under Torsion

2018 ◽  
Author(s):  
Pan Fang ◽  
Yuxin Xu ◽  
Shuai Yuan ◽  
Yong Bai ◽  
Peng Cheng
Keyword(s):  
Mechanical Behavior ◽  
Torsion Angle ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Load Condition ◽  
Element Model ◽  
Flexible Pipe ◽  
Torsional Load ◽  
Flexible Pipes ◽  
The Impact

Fibreglass reinforced flexible pipe (FRFP) is regarded as a great alternative to many bonded flexible pipes in the field of oil or gas transportation in shallow water. This paper describes an analysis of the mechanical behavior of FRFP under torsion. The mechanical behavior of FRFP subjected to pure torsion was investigated by experimental, analytical and numerical methods. Firstly, this paper presents experimental studies of three 10-layer FRFP subjected to torsional load. Torque-torsion angle relations were recorded during this test. Then, a theoretical model based on three-dimensional (3D) anisotropic elasticity theory was proposed to study the mechanical behavior of FRFP. In addition, a finite element model (FEM) including reinforced layers and PE layers was used to simulate the torsional load condition in ABAQUS. Torque-torsion angle relations obtained from these three methods agree well with each other, which illustrates the accuracy and reliability of the analytical model and FEM. The impact of fibreglass winding angle, thickness of reinforced layers and radius-thickness ratio were also studied. Conclusions obtained from this research may be of great practicality to manufacturing engineers.

scholarly journals Shear Capacity of Open Sandwich Steel Plate-Concrete Composite Slab: Experimental and Analytical Studies

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Lili Wu ◽  
Lipei An ◽  
Jiawei Li
Keyword(s):  
Failure Mode ◽  
Shear Force ◽  
Steel Plate ◽  
Concrete Slab ◽  
Experimental Studies ◽  
Shear Capacity ◽  
Crack Model ◽  
Composite Slab ◽  
Finite Element Software ◽  
Shear Performance

Considering that the fixed crack model by default of the general finite element software was unable to simulate the shear softening behavior of concrete in the actual situation, a rotational crack model based on the modified compression field theory developed by UMAT (user material) of ABAQUS software was proposed and applied to the nonlinear analysis, and a numerical simulated model for the steel-concrete composite slab was built for shear analysis. Experimental studies and numerical analyses were used to investigate the shear load-carrying capacity, deformation, and crack development in steel plate-concrete composite slab, as well as the effects of the shear span ratio and shear stud spacing on the shear performance and the contribution of the steel plate and the concrete to the shear performance. Shear capacity tests were conducted on three open sandwich steel plate-concrete composite slabs and one plain concrete slab without a steel plate. The results indicated that the shear-compression failure mode occurred primarily in the steel plate-concrete composite slab and that the steel plate sustained more than 50% of the total shear force. Because of the combination effect of steel plate, the actual shear force sustained by the concrete in the composite slab was 1.27 to 2.22 times greater than that of the calculated value through the Chinese Design Code for Concrete Structures (GB 50010-2010). Furthermore, the shear capacity of the specimen increases by 37% as the shear stud spacing decreases from 250 mm to 150 mm. By comparing the shear capacity, the overall process of load deformation development, and the failure mode, it was shown that the simulation results corresponded with the experimental results. Furthermore, the numerical simulation model was applied to analyze the influence of some factors on composite slab, and a formula of shear bearing capacity of slab was obtained. The results of the formula agreed with the test result, which could provide references to the design and application of steel plate-concrete composite slab.

Reliability Analysis of Lead-Free Solders in Electronic Packaging Using a Novel Surrogate Model and Kriging Concept

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Hamoon Azizsoltani ◽  
Achintya Haldar
Keyword(s):  
Response Surface ◽  
Electronic Packaging ◽  
Limit State ◽  
Experimental Studies ◽  
Lead Free ◽  
Evaluation Procedure ◽  
Design Parameters ◽  
State Function ◽  
Thermomechanical Loading ◽  
Lead Free Solders

A novel reliability evaluation procedure of lead-free solders used in electronic packaging (EP) subjected to thermomechanical loading is proposed. A solder ball is represented by finite elements (FEs). Major sources of nonlinearities are incorporated as realistically as practicable. Uncertainties in all design variables are quantified using available information. The thermomechanical loading is represented by five design parameters and uncertainties associated with them are incorporated. Since the performance or limit state function (LSF) of such complicated problem is implicit in nature, it is approximately generated explicitly in the failure region with the help of a completely improved response surface method (RSM)-based approach and the universal Kriging method (KM). The response surface (RS) is generated by conducting as few deterministic nonlinear finite element analyses as possible by integrating several advanced factorial mathematical concepts producing compounding beneficial effect. The accuracy, efficiency, and application potential of the procedure are established with the help of Monte Carlo simulation (MCS) and the results from laboratory investigation reported in the literature. The study conclusively verified the proposed method. Similar studies can be conducted to fill the knowledge gap for cases where the available analytical and experimental studies are limited or extend the information to cases where reliability information is unavailable. The study showcased how reliability information can be extracted with the help of multiple deterministic analyses. The authors believe that they proposed an alternative to the classical MCS technique.

Characterization of Limit State for Seismic Fragility Assessment of T-Joints in Piping System

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Ankit R. Dubey ◽  
Abhinav Gupta ◽  
Sung Gook Cho
Keyword(s):  
Limit State ◽  
Experimental Studies ◽  
State Equation ◽  
Cyclic Behavior ◽  
Piping System ◽  
Damage State ◽  
T Joints ◽  
Performance Function ◽  
A Performance

Abstract Fragility assessment requires characterization of a component or system's performance through a performance function/limit-state equation. The exceedance of limit-state is representative of failure or damage state. For the purposes of evaluating piping fragility, characterizing the behavior of T-joints through an appropriate performance function is critical, as failures in piping are generally localized at the location of T-joints, elbows, and nozzles. Past studies have utilized a monotonic rotation-based performance function. However, the existing criteria does not account for the effect of cyclic behavior. As observed during prior experimental studies, the T-joint behavior under cyclic loading is different from that under monotonic loading, and therefore, it is important to include the effects of cyclic behavior while characterizing a performance function. Moreover, the monotonic rotation-based performance function could not replicate all the leakage locations observed during experimental studies on a full-scale two-story piping system. Therefore, it is important to develop a new limit-state for accurate piping fragility assessment. This paper presents the development of a new limit state which considers the cyclic behavior of a T-joint and quantifies the number of cycles to failure.

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