• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.9
• /
• pp.6385-6390
• /
• 2015

With bending moment, torsional moment due to geometric properties as "Initial curvature" acts in horizontally curved I-girder. These behavior causes the secondary effect of bending in minor-axis because of interaction between bending and torsion. The bending and torsion interaction cause a loss of load bearing capacity by induced the early inelastic or plasticity condition in curved girder. Also eccentric load by movements of traffic can increase torsion. However, Equation of interaction between bending and torsion for straight girder, not deal with characteristics of curved girder behavior in previous studies, can be overestimated for ultimate strength in horizontally curved I-girder acting vertical force. Therefore, using more rational, obvious suggestion is required when design curved girder. In this study, we identified the bending-torsional moment interaction for the horizontally curved I-girder of the eccentric load acting by FEM analysis.

• Steel and Composite Structures
• /
• v.16 no.2
• /
• pp.157-185
• /
• 2014

This paper examines the behaviour of two types of practical open beam-to-tubular column connection details subjected to combined moment, axial and/or shear loads. Detailed continuum finite element models are developed and validated against available experimental results, and extended to deal with flexural, axial and shear load interactions. A numerical investigation is then carried out on the behaviour of selected connections with different stiffness and strength characteristics under various load combination scenarios. The influence of applied levels of axial tensile or compressive loads on the bending stiffness and capacity is examined and discussed. Additionally, the interaction effects between shear forces and co-existing bending and axial loads are examined and shown to be comparatively insignificant in terms of stiffness and capacity in most cases. It is also shown that the range of connections considered in this paper can provide rotational ductility levels in excess of those required under typical design scenarios. Based on these findings, a simplified component-based representation is proposed and described, and its ability to represent the connection response under combined loading is verified using results from detailed numerical simulations.

• Steel and Composite Structures
• /
• v.21 no.5
• /
• pp.1145-1156
• /
• 2016

To study the effects of foam core density and face-sheet thickness on the mechanical properties and failure modes of aluminum foam sandwich (AFS) beam, especially when the aluminum foam core is made in aluminum alloy and the face sheet thickness is less than 1.5 mm, three-point bending tests were investigated experimentally by using WDW-50E electronic universal tensile testing machine. Load-displacement curves were recorded to understand the mechanical response and photographs were taken to capture the deformation process of the composite structures. Results demonstrated that when foam core was combined with face-sheet thickness of 0.8 mm, its carrying capacity improved with the increase of core density. But when the thickness of face-sheet increased from 0.8 mm to 1.2 mm, result was opposite. For AFS with the same core density, their carrying capacity increased with the face-sheet thickness, but failure modes of thin face-sheet AFS were completely different from the thick face-sheet AFS. There were three failure modes in the present research: yield damage of both core and bottom face-sheet (Failure mode I), yield damage of foam core (Failure mode II), debonding between the adhesive interface (Failure mode III).

• Steel and Composite Structures
• /
• v.14 no.2
• /
• pp.173-190
• /
• 2013

The major objective of this paper is to evaluate the behavior and ultimate resisting capacity of circular CFT columns. To consider the confinement effect, proper material models with respect to the confinement pressure are selected. A fiber section approach is adopted to simulate the nonlinear stress distribution along the section depth. Material nonlinearity due to the cracking of concrete and the yielding of the surrounding steel tube, as well as geometric nonlinearity due to the P-${\Delta}$ effect, are taken into account. The validity of the proposed numerical analysis model is established by comparing the analytical predictions with the results from previous experimental studies about pure bending and eccentric axial loading. Numerical predictions using an unconfined material model were also compared to investigate the confinement effects on various loading combinations. The ultimate resisting capacities predicted by the proposed numerical model and the design guidelines in Eurocode 4 are compared to evaluate the existing design recommendation.

• International Journal of Concrete Structures and Materials
• /
• v.10 no.3
• /
• pp.373-381
• /
• 2016

As part of this study, has been developed a numerical method which allows to establish abacuses connecting the normal force with bending moment for a circular section and therefore to predict the rupture of this type of section. This may be for reinforced concrete (traditional steel) or concrete reinforced with steel fibers. The numerical simulation was performed in nonlinear elasticity up to exhaustion of the bearing capacity of the section. The rupture modes considered occur by plasticization of the steel or rupture of the concrete (under compressive stresses or tensile stresses). Regarding the fiber-reinforced concrete, the rupture occurs, usually, by tearing of the fibers. The behavior laws of the different materials (concrete and steel) correspond to the real behavior. The influence of several parameters was investigated, namely; diameter of the section, concrete strength, type of steel, percentage of reinforcement and contribution of concrete in tension between two successive cracks of bending. A comparison was made with the behavior of a section considering the conventional diagrams of materials; provided by the BAEL rules. A second comparative study was performed for fibers reinforced section.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.281-286
• /
• 2008

Wall thinning defect due to flow accelerated corrosion is one of major aging phenomena in most power plant industries, and it results in reducing load carrying capacity of the piping systems. A failure testing system was set up for real scale elbows containing various simulated wall thinning defects, and monotonic in-plane bending tests were performed under internal pressure to find out the failure behavior of thinned elbows. Various finite element models were generated and analysed to figure out and simulate the behavior for other thinning shapes and loading conditions. This paper presents the decreasing trends of load carrying capacity according to the thinning dimensions which were revealed from the investigation of finite element analysis results. A mechanical integrity evaluation model for thinned elbows was proposed, also. This model can be used to calculate the TES plastic load of thinned elbows for general internal pressure, thinning location, and in-plane bending direction.

• Structural Engineering and Mechanics
• /
• v.15 no.5
• /
• pp.495-511
• /
• 2003

New material applications and transparency are desired by contemporary architects. Its superb transparency and high strength make glass a very suitable building material -in spite of its brittleness- even for primary load bearing structures. Currently we will focus on load bearing glass beams, subjected to different loading types. Since glass beams have a very slender, rectangular cross section, they are sensitive to lateral torsional buckling. Glass beams fail under a critical buckling load at stresses that lie far below the theoretical simple bending strength, due to the complex combination of torsion and out-of-plane bending, which characterises the instability phenomenon. The critical load can be increased considerably by preventing the upper rim from moving out of the beam's plane. Different boundary conditions are examined for different loading types. The load carrying capacity of glass beams can be increased three times and more using relatively simple, cheap lateral restraints.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.8 s.185
• /
• pp.154-162
• /
• 2006

By laying its drum horizontally, front-loaded washing machine mostly used in Europe that uses the head of the water to launder was appropriate for washing only small amount of laundry. However, the demands of customers are requiring front-loaded washing machine to handle big capacity laundry as well, and have faster rotation speed to increase drying ability. To meet such demands, more stress from bending and twisting are complexly loaded onto the shaft supporting the horizontal drum, causing problems in fracture strength and fatigue life. Shafting system is mainly divided into flange and shaft. Flange is located between the drum and shaft, transferring power from the shaft to drum, and acting as a supporter of the back of the drum. Shaft is connected from the flange to insert production, transferring power from the motor to drum, and mainly acting as stiffness against the horizontal weight of the shafting system. In this paper, strength analysis and experiment were executed on both the shaft and flange of front-loaded washing machine to suggest the design improvement of shafting system for big capacity, high-rotation drying. Also, verification of this evaluation was executed on fracture strength and fatigue life for studied shaft system.

• Structural Engineering and Mechanics
• /
• v.77 no.4
• /
• pp.509-521
• /
• 2021

The neighbouring gaps at the mortise-tenon joint in traditional timber structure, which leads to the complexity of the joint, are considered to impair the mechanical performance of the joint. In this paper, numerical simulation of loose joint was conducted to examine the deformation states, stress distributions, and bearing capacities, which was verified by full-scale test. On the basis of the experimental and numerical results, a simplified mechanics model with gaps has been proposed to present the bending capacity of the loose joint. Besides, the gap effects and parameter studies on the influences of tenon height, friction coefficient, elastic modulus and axial load were also investigated. As a result, the estimated relationship between moment and rotation angle of loose joint showed the agreement with the numerical results, demonstrating validity of the proposed model; The bending bearing capacity and rotational stiffness of loose joint had a certain drop with the increasing of gaps; and the tenon height may be the most important factor affecting the mechanical behaviors of the joint when it is subjected to repeated load; Research results can provide important references on the condition assessments of the existing mortise-tenon joint.

• Structural Engineering and Mechanics
• /
• v.81 no.5
• /
• pp.539-550
• /
• 2022

A detailed experimental program was conducted to investigate the flexural behavior of ultra high performance concrete (UHPC) beams reinforced with high strength steel (HSS) rebars with a specified yield strength of 600 MPa via direct tensile test and monotonic four-point bending test. First, two sets of direct tensile test specimens, with the same reinforcement ratio but different yield strength of reinforcement, were fabricated and tested. Subsequently, six simply supported beams, including two plain UHPC beams and four reinforced UHPC beams, were prepared and tested under four-point bending load. The results showed that the balanced-reinforced UHPC beams reinforced with HSS rebars could improve the ultimate load-bearing capacity, deformation capacity, ductility properties, etc. more effectively owing to interaction between high strength of HSS rebar and strain-hardening characteristic of UHPC. In addition, the UHPC with steel rebars kept strain compatibility prior to the yielding of the steel rebar, further satisfied the plane-section assumption. Most importantly, the crack pattern of the UHPC beam reinforced with HSS rebars was prone to transform from single main crack failure corresponding to the normal-strength steel, to multiple main cracks failure under the condition of balanced-reinforced failure, which validated by the conclusion of direct tensile tests cooperated with acoustic emission (AE) source locating technique as well.