scholarly journals NUMERICAL ANALYSIS AND EVALUATION OF EFFECTIVE SLAB WIDTH OF COMPOSITE CONTINUOUS BEAMS WITH SEMI-RIGID JOINT

The characterization of the structural behavior of composite beams is directly affected by the determination of the effective slab width. Various codes propose their own definitions of the effective width based on the beam span and the slab width parameters. However, the evaluation of the effective width may be influenced by other parameters. The aim of this work is to determine the most important factors affecting effective width for continuous composite beams with semi-rigid joints using numerical simulations. A three-dimensional finite element model of a composite continuous beam using explicit-solver available in ABAQUS is developed. The proposed model is validated through comparisons to available experimental results. A modified model is proposed based on the so-validated model to study the influence of the composite beam-column joint stiffness on the effective width. Then, both numerical models are used to perform an extensive parametric study to investigate the influence of various parameters on the estimation of the effective slab width. The influence of slab width, the shear connection degree, and composite joint stiffness are particularly analyzed to find out the most important parameters influencing the effective width so that simplified equations for the calculation of the effective slab width are proposed.

2017 ◽  
Vol 893 ◽  
pp. 380-383
Author(s):  
Jun Xia ◽  
Z. Shen ◽  
Kun Liu

The tapered cross-section beams made of steel-concrete composite material are widely used in engineering constructions and their dynamic behavior is strongly influenced by the type of shear connection jointing the two different materials. The 1D high order finite element model for tapered cross-section steel-concrete composite material beam with interlayer slip was established in this paper. The Numerical results for vibration nature frequencies of the composite beams with two typical boundary conditions were compared with ANSYS using 2D plane stress element. The 1D element is more efficient and economical for the common tapered cross-section steel-concrete composite material beams in engineering.


Author(s):  
Hao Gong ◽  
Jianhua Liu ◽  
Xiaoyu Ding

An understanding of conditions that trigger the loosening of bolted joints is essential to ensure joint reliability. In this study, a three-dimensional finite element model of a typical bolted joint is developed, and a new simulation method is proposed to quantitatively identify the critical transverse force for initiating loosening. This force is used to evaluate the anti-loosening capacity of bolted joints. Using the proposed simulation method, the effects of factors affecting critical loosening are systematically studied. It is found that the preload, frictional coefficients at the thread and the bearing surfaces, clamped length, and fit tolerance mainly affected loosening. When the preload and friction coefficients are increased, and the clamped length and fit tolerance are reduced, loosening is inhibited. Experiments are performed to demonstrate the reliability of the results. Finally, a suggestion is proposed to improve the design guideline VDI 2230 for bolted joints, which considers the requirement of avoiding loosening under vibrational loading.


2011 ◽  
Vol 219-220 ◽  
pp. 1211-1214
Author(s):  
Wei Jiang

Finite element simulation is an efficient method for studying factors affecting weld-induced residual stress distributions. In this paper, a validated three-dimensional finite element model consisting of sequentially coupled thermal and structural analyses was developed. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were perceived to generate the least distortion in actual welding circumstances, were proposed and their influences on the residual stress fields in a thick-walled tee joint were investigated. Appropriate conclusions and recommendations regarding welding sequences are presented.


2016 ◽  
Vol 20 (10) ◽  
pp. 1451-1465 ◽  
Author(s):  
Shou-Chao Jiang ◽  
Gianluca Ranzi ◽  
Ling-Zhu Chen ◽  
Guo-Qiang Li

This article presents an extensive experimental and numerical study aimed at the evaluation of the thermo-structural response of composite beams with composite slabs. Two full-scale fire tests were carried out on simply supported composite steel-concrete beams with steel sheeting perpendicular and parallel to the steel joist, respectively. Both specimens were observed to fail by developing large displacements. Concrete crushing at the mid-span, debonding of the profiled sheeting and spalling of the fire protection were observed during both tests. A three-dimensional finite element model was developed in ABAQUS, and its accuracy was validated against the experimental measurements collected as part of this study. The model was then used to perform a parametric study to determine the influence of the degree of shear connection, load ratio and design fire rate on the structural response of composite beams at elevated temperatures. These results, together with experimental data available in the literature, were used to evaluate the ability of European guidelines to predict the critical temperature of composite beams. It was shown that predictions from Eurocode 4 were safe and provided conservative estimates for most cases.


Author(s):  
Liang Cheng ◽  
Qing Wang ◽  
Yinglin Ke

In order to investigate the effect of shim compensation for nonuniform gaps in aircraft assembly, the influence of the shims with different material and parameters on bolted joints is studied in this paper. According to the real material and assembly conditions of the aircraft joint structures, the specimen and experiment are designed to obtain the tensile performance of the joint structures with different shims. A three-dimensional finite element model, which incorporates the Johnson–Cook material property of the alloys, traction-separation law of liquid shims, contact relationships between the joint elements, and boundary conditions of the tensile process, is established with the specimen configurations. After validating through comparing with the experimental results, the modeling method is adopted to simulate the tensile response of the bolted joints with shims. Furthermore, both the influence of the shim material and thickness on the mechanical behaviors of bolted joints is investigated in detail. Shims can considerably reduce the assembly stress of joint structures and improve the joint stiffness and load capacity, and this effect is more remarkable with the increase of gap values. Liquid shims improve the joint stiffness due to its cohesive ability, while solid shims improve the joint load capacity. Hybrid shims possess a composite shimming effect of liquid and solid shims. Whatever the shim material is applied, the joint stiffness and strength drop with the growth of shim thickness, so strict deviation control method should be taken to ensure the assembly gaps as small as possible. The research results enhance the knowledge of shimming effect on joint structures, and thus offer positive guidance for practical application in aircraft assembly.


2021 ◽  
Vol 8 ◽  
Author(s):  
Wei Wang ◽  
Xie-dong Zhang ◽  
Xi-long Zhou ◽  
Lin Wu ◽  
Hao-jie Zhu

Multi-bolt shear connectors (MBSCs), arranging bolts as a group in several rows, can be applied in prefabricated steel–concrete composite beams or bridges (SCCBs) to reduce the construction time and meet the requirements of sustainable development. The mechanical behavior of bolt shear connectors has been broadly investigated in recent years, but they were mainly focused on the normal arrangement. The shear performance of MBSCs is not consistent with that of the same number of single bolts. In this study, a three-dimensional (3D) finite element model (FEM) was developed to investigate the multiple bolts effect and its mechanical performance. Material non-linearities and the interactions among all components were included in the FEM. The accuracy and reliability of the proposed FEM were initially verified against the available push-out test results. The validated FEM further studied the load–slip relationship, shear capacity, and shear stiffness of the MBSCs. A parametric study was carried out to determine the effect of the bolt spacing, bolt row numbers, the concrete strength, and the bolt diameter on the shear performance of MBSCs. Based on the extensive parametric analyses, design recommendations considering the multiple bolts effect for predicting the shear resistance per bolt in multi-bolt connectors were proposed and verified.


2019 ◽  
Vol 56 (3) ◽  
pp. 398-419 ◽  
Author(s):  
Albrecht von Boetticher ◽  
Axel Volkwein

Chain-link mesh is one of several net types used as protection against rockfall, shallow landslides, and debris flows. The dynamic impact and the corresponding nonlinear barrier response require numerical models. Chain-link meshes show a nonlinear anisotropic behaviour caused by the geometry of the wire. Resolving this geometry and its deformation results in a bottleneck of numerical costs. We present a discrete element model that covers the nonlinear and anisotropic behaviour of the chain-link mesh, using results from either small-scale, quasi-static tension tests or from a detailed mechanical model as material-law input. The mesh stiffness, resistance, and failure depend on the inner mesh opening angle and thus on the direction of deformation. This information enters the model through the transformation of the nonlinear, three-dimensional deformation processes into a nonlinear material law, with an interpolated dependency on the inner mesh angle. The model maps the resistance of the mesh against impacting masses and covers the energy absorption and it is capable of predicting the dynamic behaviour of different protection barriers with high accuracy, optimized calculation time, and minimized calibration efforts. This is illustrated by high impact energy tests that follow the ETAG027 standard, and also with a rockfall attenuating system.


2005 ◽  
Vol 293-294 ◽  
pp. 591-598 ◽  
Author(s):  
C.T. McCarthy ◽  
M.A. McCarthy ◽  
Michael D. Gilchrist

A three-dimensional finite element model of a three-bolt, single-lap composite joint is constructed using the non-linear finite element code MSC.Marc. The model is validated against an experiment where the load distribution in the joint is measured using instrumented bolts. Two different joint configurations are examined, one with neat-fit clearances at each bolt-hole and another with a 240 µm clearance at one hole with neat-fits at the others. Bearing and by-pass stresses are extracted from the model and used in conjunction with published bearing/by-pass diagrams to predict the failure load, mode and location for the joints. It is shown that the proposed model accurately predicts the failure behaviour of the joints, as determined from experiments on three-bolt joints loaded to failure. It is also shown that introducing a clearance into one hole significantly changes the failure sequence, but does not affect the ultimate failure load, mode or location. The proposed method demonstrates a simple approach to predicting damage in complex multi-bolt composite joints.


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