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The structural steel design specification in Canada, CSA S16-14, uses the same equations for the design of rolled and welded shape beams for lateral torsional buckling (LTB). A recent study has shown that the current design equations might overestimate the capacity of welded wide flange (WWF) beams. This paper evaluates the performance of the current design equations in providing LTB capacities of welded I-shape beams (WWF beams). An extensive finite element (FE) analysis is performed for simply supported WWF beams subjected to constant moment. In total, 256 FE models are analyzed and it is observed that both CSA and AISC overestimate the LTB capacity of welded I-shape beams by as much as 37%, particularly when residual stress measured at Lehigh University is used in the analysis. Also, the Eurocode is found to be conservative and the proposed equation by MacPhedran and Grondin in 2011 provides better predictions of LTB strengths of WWF shapes than the current CSA approach. [ABSTRACT FROM AUTHOR]

The convex model approach is applied to derive the robust seismic fragility curves of a five-span isolated continuous girder bridge with lead rubber bearings (LRB) in China. The uncertainty of structure parameters (the yield force and the post-yield stiffness of LRB, the yield strength of steel bars, etc.) are considered in the convex model, and the uncertainty of earthquake ground motions is also taken into account by selecting 40 earthquake excitations of peak ground acceleration magnitudes ranging from 0.125 to 1.126 g. A 3-D finite element model is employed using the software package OpenSees by considering the nonlinearity in the bridge piers and the isolation bearings. Section ductility of piers and shearing strain isolation bearings are treated as damage indices. The cloud method and convex model approach are used to construct the seismic fragility curves of the bridge components (LRB and bridge piers) and the bridge system, respectively. The numerical results indicate that seismic fragility of the bridge system and bridge components will be underestimated without considering the uncertainty of structural parameters. Therefore, the failure probability P had better be served as the seismic fragility, especially, the fragility of the bridge system is largely dictated by the fragility of LRB. Finally, the probabilistic seismic performance evaluation of the bridge is carried out according to the structural seismic risk estimate method. [ABSTRACT FROM AUTHOR]

This paper presents a two-step approach for structural damage identification in beam structure using the influence line and bird mating optimizer (BMO). Local damage is simulated as the reduction of the elemental Young's modulus and mass of beam element. The technique for damage localization based on influence line and its derivatives before and after damage for beam structure was outlined. An objective function comprised of dynamic acceleration is utilized for BMO algorithm. The dynamic response data under external force is calculated by Newmark integration method. Numerical examples of a simply supported beam was investigated. Effect of measurement noise is studied. Studies in the paper indicate that the proposed method is efficient and robust for identifying damages in beam structures. [ABSTRACT FROM AUTHOR]

This paper investigates multi-objective Neutrosophic Optimization (NSO) approach to optimize the cost of welding and deflection at the tip of a welded steel beam, while the maximum shear stress in the weld group, maximum bending stress in the beam, and buckling load of the beam have been considered as constraints. The problem of designing an optimal welded beam consists of dimensioning a welded steel beam and the welding length so as to minimize its cost, subject to the constraints as stated above. The purpose of the present study firstly to investigate the effect of truth, indeterminacy and falsity membership function in neutrosophic optimization in perspective of welded beam design and secondly is to analyse the results obtained by different optimization methods like fuzzy, intuitionistic fuzzy so that the welding cost of the welded steel beam become most cost effective with minimum deflection. Specifically based on truth, indeterminacy and falsity membership function, a multi objective NSO algorithm has been developed to optimize the welding cost, subjected to a set of constraints. It has been shown that NSO is an efficient method in finding out the optimum value in comparison to other iterative methods for nonlinear welded beam design in imprecise environment till investigated. Numerical example is also given to demonstrate the efficiency of the proposed NSO approach. [ABSTRACT FROM AUTHOR]

This paper develops a solution procedure of Neutrosophic Optimization (NSO) to solve optimum welded beam design with inexact co-efficient and resources. Interval approximation method is used here to convert the imprecise co-efficient which is a triangular neutrosophic number to an interval number. We transform this interval number to a parametric interval valued functional form and then solve this parametric problem by NSO technique. Usually interval valued optimization consist of two level mathematical programs, but a parametric interval valued optimization in neutrosophic environment is direct approach to find the objective function, this is the main advantage. In this paper we have considered a welded beam design with cost of welding as objective and the maximum shear stress in the weld group, maximum bending stress in the beam, buckling load of the beam and deflection at the tip of a welded steel beam as constraints .Numerical example is given here to illustrate this structural model through this approximation method. [ABSTRACT FROM AUTHOR]

Laser oscillating welding was employed to join 4 mm-thick AA6061-T6 aluminum alloy in butt configuration. Three beam oscillating patterns that are transversal, longitudinal and circular were studied. The beam oscillation improved the weld morphologies and promoted the formation of equiaxed grain within the fusion zone due to stirring effect. The circular oscillation obtained the soundest weld, the finest grain and the most amount of equiaxed grains within the weld. The beam oscillation almost had no effect on the tensile strength of the weld, but increased the ductility obviously. The strain of circularly oscillating weld was up to 8%, 38% higher than the weld without beam oscillation. The ductility improvement was attributed to the decrease of weld morphological defects and the increase of equiaxed grains. Besides, the improving mechanisms of weld characterization were discussed by the beam oscillating effect on the behaviors of laser keyhole and melt flow. [ABSTRACT FROM AUTHOR]

This paper presents the modal analysis for the calculation of total and modal dynamical responses in displacements and bending moments for rectangular plate loaded with a uniformly distributed forces over the entire surface. Using the multiplier dynamic function is simplifies the dynamic methodology calculation of plates. The method considered the shapes functions of plates vibrations as the product of beams shape functions having the same limits conditions. The results obtained in this paper reveal the most dangerous sections of the structure relative to the x and y axes. [ABSTRACT FROM AUTHOR]

The peculiarities of methods of restriking of plastic deformation during production of center girder of gondola cars are presented. The paper traverses the reasonable use of heat impact free restriking of center girder of gondola cars. The classification of methods of restriking of permanent deformation after welding for carriage building. [ABSTRACT FROM AUTHOR]

Pressure-impulse diagrams are commonly used in preliminary blast resistant design to assess the maxima of damage related parameter(s) in different types of structures as a function of pulse loading parameters. It is well established that plastic dynamic response of elastic-plastic structures is profoundly influenced by the temporal shape of applied pulse loading (Youngdahl, 1970, "Correlation Parameters for Eliminating the Effect of Pulse Shape on Dynamic Plastic Deformation," ASME, J. Appl. Mech., 37, pp. 744-752; Jones, Structural Impact (Cambridge University Press, Cambridge, Eng-land, 1989); Li, and Meng, 2002, "Pulse Loading Shape Effects on Pressure-Impulse Diagram of an Elastic-Plastic, Single-Degree-of-Freedom Structural Model," Int. J. Mech. Sei., 44(9), pp. 1985-1998). This paper studies pulse loading shape effects on the dynamic response of continuous beams. The beam is modeled as a single span with symmetrical semirigid support conditions. The rotational spring can assume different stiffness values ranging from 0 (simply supported) to oo (fully clamped). An analytical solution for evaluating displacement time histories of the semirigidly supported (contin-uous) beam subjected to pulse loads, which can be extendable to very high frequency pulses, is presented in this paper. With the maximum structural deflection, being gener-ally the controlling criterion for damage, pressure-impulse diagrams for the continuous system are developed. This work presents a straightforward preliminary assessment tool for structures such as blast walls utilized on offshore platforms. For this type of structures with semirigid supports, simplifying the whole system as a single-degree-of-freedom (SDOF) discrete-parameter model and applying the procedure presented by Li and Meng (Li and Meng, 2002, "Pulse Loading Shape Effects on Pressure-Impulse Diagram of an Elastic-Plastic, Single-Degree-of-Freedom Structural Model," Int. J. Mech. Sei., 44(9), pp. 1985-1998; Li and Meng, 2002, "Pressure-Impulse Diagram for Blast Loads Based on Dimensional Analysis and Single-Degree-of-Freedom Model," J. Eng. Mech., 128(1), pp. 87-92) to eliminate pulse loading shape effects on pressure-impulse diagrams would be very conservative and cumbersome considering the support conditions. It is well known that an SDOF model is a very conservative simplification of a continuous system. Dimensionless parameters are introduced to develop a unique pulse-shape-independent pressure-impulse diagram for elastic and elastic-plastic responses of continuous beams. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents experimental and numerical investigations on multi-layered timber beams using welded-through wood dowels in place of traditional poly(vinyl acetate) (PVAc)-adhesives (or metallic nails). Four-layer beams were constructed with varying numbers of dowels, in each, and then loaded using four-points bending tests to evaluate the mechanical performance of these beams. The practical difficulties encountered in constructing deeper multi-layer beams are discussed and possible solutions which have been employed for the purpose of this work, and proved successful are presented. In order to investigate thoroughly the full potential of multi-layered beams with a very limited number of experimental studies, a 3D FE model has been presented, validated against experimental results and then used to study some influential parameters. The results showed that a reasonable bending stiffness of multi-layered beams is achievable with a good combination of material and geometric parameters. [Copyright &y& Elsevier]

Cracked cross-beam connections made of thin-walled rectangular hollow sections (RHS) are repaired with carbon fiber-reinforced polymer (CFRP) sheets. Constant amplitude fatigue experiments are conducted on the repaired specimens. A pilot test is conducted on a T-connection of square hollow sections (SHS) to explore the effective method of applying CFRP. Due to the peeling effect at the corner region of the SHS-to-SHS connection, early debonding happens in the pilot test that only results in a slight extension in fatigue life. In the following experiments of repairing RHS-to-RHS cross-beam connections, circumferential or transverse restraining CFRP patches are applied in the corner region that prevents early debonding successfully and leads to significant increase in fatigue life. Finally, an improvement is made with the addition of steel strengthening plates that increase both the flexural stiffness and fatigue life of the cracked specimens significantly. The proposed retrofitting method may be useful for repairing other similar fatigue-cracked welded tubular connections. [ABSTRACT FROM AUTHOR]

The article focuses on a study which presents an algorithm model for the cost optimization of concrete beams based on the specifications of the SR EN 1994-1-1/2006 standard. It cites different techniques and objective functions for optimizing composite structures. It introduces the structural mass minimization, in the context of a highway bridge composite welded plate girder.

Abstract: A series of tests were executed for H-shaped beams whose flanges were connected to end-plate by non-completely penetrated welds. The welds were designed by equal capacity rule and the beams were mainly composed of non-compact or slender elements. The parameters introduced are width–thickness ratios of beam flange and web, end-plate thickness, angle between flange plane and end-plate plane and so on. 24 pieces of specimens were tested to failure under monotonic loading and 6 under cyclic loading. For comparison, a few of the specimens are those with completely penetrated groove welds. Finite element (FE) analysis was also carried out to study the effect of parameter change on the resistance of the welds. The parameters involved end-plate thickness, weld size, column flange thickness and bolt gauge. The results show that thinner end-plate and greater bolt gauge will deteriorate the resistance of weld. As long as the components are properly designed, as done in tests, the connections will not fail at the welds no matter what kind of weld form is adopted. In addition, weld form has no obvious effect on the ultimate loads and cyclic behavior of specimens. It is confirmed that the non-completely penetrated welds connecting flanges of H-shaped beams and end-plates can be used both under static loading and seismic loading in low-rise building structure where local buckling of the member is the predominant factor. [Copyright &y& Elsevier]