Rectangular Hollow Beams Research Articles

Study on the Shear Characteristics of Perforated Lean Duplex Stainless Steel Rectangular Hollow Beams

Abstract: The paper deals with the shear behavior of the Lean duplex stainless steel perforated hollow beams. Lean duplex stainless steel offers significant advantages such as better economy, improved strength, high temperature properties, acceptable, weldability and fracture toughness properties. Hollow beams have wide range of applications in the construction industry, such as in buildings, bridges, oil refineries etc. The ultimate strength and elastic stiffness of a structural member can vary with perforation position, size, shape, and orientation. In this study the shear behaviour of perforated hollow beam is studied based on different shapes of perforation. . Different shapes of perforation mainly include circle, square and diamond. ANSYS Workbench is used to analyze the shear behavior of perforated lean duplex stainless steel rectangular hollow beams.

Behaviour of cold-formed steel hollow beam with perforation under flexural loading

Cold-formed steel (CFS) is widely used as structural members in roof trusses, wall panels and claddings, storage racks and support structures. Nowadays, CFS is proposed to use as building components as beam and column etc. Owing to the very small thickness, the failure of the beam and column with perforation was mainly by excessive buckling and deformation. Thus, the behaviour of cold-formed steel hollow beam with web openings under flexural loading must be studied. In this study two different tubular cross section, shape and the position of the web openings were considered. The objective of the study is to examine the flexural strength, failure mode, load-deflection and load-strain behaviour of the cold-formed steel hollow beams with or without web openings under flexure. From the experimental study it was observed that square hollow beam fails by local and overall buckling whereas the rectangular hollow fails only by outward local buckling. The flexural strength of rectangular hollow beam was increased by 41% as compared to square hollow beam. The finite element model using ANSYS, was validated against the experimental results. A nonlinear finite element model shows good agreement with the experimental results.

Shear behavior of stiffened single perforated lean duplex stainless steel (LDSS) rectangular hollow beams

This paper presents the study on shear behavior of stiffened single perforated LDSS rectangular hollow beam, considering various orientations / patterns viz., inclined (IS), vertical (VS), horizontal (HS) and ring (RS); and effect of various cross-sections i.e. flat, angular and semi-circular (considering same material consumption). Based on the study, it has been found that in general, inclined stiffener (with flat cross-section) is relatively most effective in enhancing the shear capacity of perforated beams. For the inclined stiffeners, it is observed that the rate of increase in shear capacity (Vu/Vy) increases (in a non linear trend) with increasing stiffener length for higher stiffener thicknesses. In the case of vertical and horizontal stiffeners, there appears to have no/little significant improvement in shear capacity for both the variation in length, width and thickness. For the ring stiffeners, it is found that, shear capacity increases with increase in both breadth and thickness of the stiffeners. Comparison made between angular and semi-circular sections (keeping the same cross sectional area) showed that both the sections predicted similar behavior of shear capacity.

Parametric Study of Longitudinal Hollow Steel Fibre Reinforced Concrete (SFRC)Beams

The main aim of this study is to investigate on the crack patterns and flexural strength of simply supported RC rectangular hollow beams and SFRC rectangular hollow beams (with a circular hole in longitudinal direction) under a loading frame with a gradual increasing load. The experimental program consists of casting and testing of 4RC and 4 SFRC beams of size 1400 × 150 × 150. M 25 grade of concrete was used for the casting of all the beams. Hollow beams were made using pipes of diameters 32mm, 40mm and 50mm and the position of placing the pipes are at a distance of 3 to 4 cm from bottom reinforcement. All other properties of the beam were kept constant such as the cross section of the beam and the amount of longitudinal steel. In this study we also focus on the material management by the introduction of a hollow core. By this material optimization we can decrease the dead loads which contributes to the seismic effect in high rise buildings. The influence of area of hole is taken as reference for the study. A comparison of experimental results of RC and SFRC were made to predict the crack behaviour and the flexural load carrying capacity of hollow beams.

Shear behaviour of single perforated lean duplex stainless steel (LDSS) rectangular hollow beams

In this work, the effect of single circular perforation in the shear behaviour of LDSS rectangular hollow beams has been presented using finite element analyses, in a systematic manner, considering a key cross sectional parameters viz., flange thickness, flange width, web thickness, shear span etc. Predominantly, the effects of single perforation size / diameter and location (along longitudinal, transverse, and diagonals) are determined with an attention on the shear load capacity (Vu/Vy), deformed shapes (or failure modes) etc. The effects of the perforation are presented parametrically in relation to web slenderness (hw/tw) and flange to web thickness ratio (tf/tw). The FE results are then compared with the newly amended stainless steel European design code (EN 1993-1-4, 2006/A1:2015) [8]. Additionally, based on the current FE understanding, new design expressions for shear buckling factor are proposed.

Shear characteristics of Lean Duplex Stainless Steel (LDSS) rectangular hollow beams

A numerical investigation on the shear characteristics of Lean Duplex Stainless Steel (LDSS) rectangular hollow beams are presented in this paper, through a parametric study, using the commercial finite element software, Abaqus. Effects of key cross sectional parameters viz., flange thickness (tf), flange width (wf), web thickness (tw) and shear span (a) have been considered, keeping the height of the web (hw) constant. It is observed that increasing flange thickness for the same web thickness, can enhance both shear capacity and ductility. The shear capacity of the beam is seen to decrease with increasing shear span, the decrease being ~32–36%, for 100% increase in shear span (a/hw). The effect of increasing flange width is found to be relatively significant for stockier cross sections as compared to that of slender sections. Three failure mechanisms have been identified viz., 1) shear dominant, 2) bending dominant, and 3) combined shear and bending. In general, both EN 1993-1-4 (2006/A1:2015) and DSM are found to be applicable for the shear design of LDSS rectangular hollow beams. Possible modifications to both EN 1993-1-4 (2006/A1:2015) and DSM have been suggested by bifurcating into two span ratios: 1) a/hw≤1.0 and 2) 1<a/hw≤2.0.

Gyrator transform of four-petal Gaussian beam and generation of rectangular hollow beam

Four-petal Gaussian beam is a special type of Gaussian beam, and its propagation properties are widely used in micro optics, optical communication and splitting technology. Recently, the generations and the properties of different types of hollow beams have become a hot research topic, such as research on hollow optical vortex beams. The Gyrator transform can be used to fulfill the mode conversion of laser beam. In this paper, based on the Gyrator transform, the analytical expression of four-petal Gaussian beam passing through such a transform system is derived, and the intensity distribution and the corresponding phase distribution associated with the transforming four-petal Gaussian beam are analyzed by numerical simulations. It is found that the four-petal Gaussian beam can be transformed into rectangular hollow beam by Gyrator transform, under the appropriate conditions of the beam order, the beam parameter, the transform angle of Gyrator transform, and the waist width. For the beam order n=m=3, the transform angle of Gyrator transform = 0.4133, the beam parameter K=30, and the waist width = 0.9, the rectangular hollow optical vortex beams can be obtained. Under such conditions, the maximum intensities appear in the four corners, and they are almost uniform on the four sides. The effects of the beam parameters, the transform angle, and the beam order on the distributions of intensity and phase of the rectangular hollow beam are analyzed in detail. The numerical results show that for the beam parameter K10, the rectangular hollow beam always is obtained, and for a lager beam parameter, the intensity distribution of the rectangular hollow beam is more uniform. Different beam order generates different type of hollow beam. For example, for n=m = 2, = 1.2, K = 30, and = 0.5409, a new strange circular hollow beam with solid circular nucleus can be obtained. The transform angle of Gyrator transform has a significant effect on the energy distribution of the hollow beam. When the transform angle changes in a small range, the uniformity of the intensity distribution of the rectangular hollow beam is lost. The bigger the transform angle change, the more serious the loss of uniformity of the hollow beam intensity is. The size of the hollow beam bright ring is determined by the waist width of the four-petal Gaussian beam: the larger the waist width, the smaller the bright ring is. The results further enriches the applications of Gyrator transform system and the four-petal Gaussian beam in the beam shaping.

Free vibration of horizontally curved thin-walled beams with rectangular hollow sections considering two compatible displacement fields

ABSTRACTA finite element is presented for vibration analyses of horizontally curved thin-walled rectangular hollow beams. Eight cross-section deformation modes are employed to describe the mid-surface contour displacement field with the modal superposition method. Focused on the in-plane moment equilibrium condition and the displacement continuity condition, two compatible displacement fields are constructed to calculate the strain energy and the kinetic energy of the beam, respectively. With the application of Hamilton’s principle the dynamic governing equations are formulated, and then approximated for the finite element implementation. Finally, numerical examples are illustrated to verify the validity of the present theory.

用波晶片产生可调矩形空心光束

用波晶片产生可调矩形空心光束

Design and Optimization of Portable Foot Bridge

Portable footbridge provide a solution that will aid a person carrying a load in crossing streams; which is portable, easy to install and dismantle. In this paper effort has been made to design and optimize such footbridge. The basic emphasis has been given to minimize the total deformation of the structural member by optimizing the cross sections, material properties and weight. The structural member consists of a rectangular plate of length 1.5m, 0.5m width and thickness of 3mm fixed on the frame of prismatic beams at the periphery and in between. A three dimensional model was developed using SolidWorks. Six different cross sections (circular, rectangular and square with solid and hollow sections) of the beam with three different materials (Aluminium alloy, Structural steel and Titanium alloy) were analyzed in ANSYS 11.0 with similar loading and support conditions. The results obtained, after analysis of different cross sections and with different materials, were compared. Rectangular hollow beam of Aluminum alloy with dimension 60mm×40mm×3mm (thickness) was considered for the structural member of the portable footbridge after optimization.

Lateral buckling strengths of cold-formed rectangular hollow sections

Code rules for designing steel beams against lateral buckling which are based on data for hot-rolled I-sections are unnecessarily conservative when used for cold formed rectangular hollow section beams. Cold-formed rectangular hollow section beams have different stress-strain curves, residual stresses, and crookedness and twist. The effects of residual stress on the inelastic buckling of I-section beams are not nearly as pronounced for hollow sections with two webs, while the strengthening effects of pre-buckling deflections are greater for hollow sections. Simplistic code rules for top flange loading are very conservative when applied to hollow sections. This paper reviews elastic lateral buckling behaviour and the strength rules used to design steel beams. It develops realistic models for cold-formed rectangular hollow beams which are analysed to predict the effects of moment distribution, load height and yield stress on their strengths. The results of the analyses are used to develop improved design rules which remove much of the conservatism of present design rules.