• Title/Summary/Keyword: Welded structures

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An Experimental Study on the Fatigue Strength of Rolling Stock Structures (철도차량 구조물의 피로강도에 관한 실험적 연구)

  • Goo Byeong-choon;Kim Jae-Hoon;Oh Chang-rok;Kim Dae-Jin
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.878-882
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    • 2004
  • We investigated the effect of weld details on fatigue behavior of a material, JIS SM 490 A, with yielding strength of about 350 MPa and tensile strength of about 520 MPa. Tensile tests, instrumented indentation tests and fatigue tests were carried out on double V-grooved butt weld plates such as reinforcement removed, as-welded and weld toe ground. In addition plates with transverse fillet welded web, load carrying cruciform fillet welded plates, non-load-carrying cruciform fillet welded plates, longitudinal butt welded plates and welded rectangular life-size box beams were tested. S-N curves for the above specimens were obtained and analyzed.

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A Study on Fatigue Design for Welded Joint of STS301L (STS301L 용접종류별 이음재의 피로설계에 관한 연구)

  • Baek, Seung-Yeb
    • Journal of Welding and Joining
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    • v.28 no.3
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    • pp.86-91
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    • 2010
  • Stainless steel sheets are widely used as the structural material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug type joint, it is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. And also, the influence of the geometrical parameters of gas welded joints on stress distribution and fatigue strength must be evaluated. the ${\Delta}P-N_f$ curves were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curves were rearranged in the ${\Delta}{\sigma}-N_f$ relation with the maximum stress at the edge of fillet welded joint.

A complete integrity assessment of welded connections under high and low cycle fatigue followed by fracture failure

  • Feng, Liuyang;Liu, Tianyao;Qian, Xudong;Chen, Cheng
    • Steel and Composite Structures
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    • v.43 no.4
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    • pp.465-481
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    • 2022
  • This paper presents a comprehensive integrity assessment of welded structural components, including uniform high- and low-cycle fatigue assessment of welded plate joints and fatigue-induced fracture assessment of welded plate joints. This study reports a series of fatigue and fracture tests of welded plate joints under three-point bending. To unify the assessment protocol for high- and low-cycle fatigue of welded plate joints, this study develops a numerical damage assessment framework for both high- and low-cycle fatigue. The calibrated damage material parameters are validated through the smooth coupon specimens. The proposed damage-based fatigue assessment approach describes, with reasonable accuracy, the total fatigue life of welded plate joints under high- and low-cycle fatigue actions. Subsequently, the study performs a tearing assessment on the ductile crack extension of the fatigue-induced crack. The tearing assessment diagram derives from the load-deformation curve of a single-edge notched bend, SE(B) specimen and successfully predicts the load-crack extension relation for the reported welded plate joints during the stable tearing process.

An experimental study of the behaviour of double sided welded plate connections in precast concrete frames

  • Gorgun, Halil
    • Steel and Composite Structures
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    • v.29 no.1
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    • pp.1-22
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    • 2018
  • Multi-storey precast concrete skeletal structures are assembled from individual prefabricated components which are erected on-site using various types of connections. In the current design of these structures, beam-to-column connections are assumed to be pin jointed. Welded plate beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is at present limited information concerning their detailed structural behaviour under bending and shear loadings. The experimental work has involved the determination of moment-rotation relationships for semi-rigid precast concrete connections in full scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and weld arrangements conformed with successful commercial practice. Proprietary hollow core slabs were tied to the beams by tensile reinforcing bars, which also provide the in-plane continuity across the connections. The strength of the connections in the double sided tests was at least 0.84 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.7 to 3.9 times the flexural stiffness of the attached beam. When the connections were tested without the floor slabs and tie steel, the reduced strength and stiffness were approximately a third and half respectively. This remarkable contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. In general, the double sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided welded plate connection test results are presented in this paper. The behaviour of single sided welded plate connection test results is the subject of another paper.

Reduction of residual stress for welded joint using vibrational load

  • Aoki, Shigeru;Nishimura, Tadashi;Hiroi, Tetsumaro
    • Steel and Composite Structures
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    • v.4 no.5
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    • pp.355-365
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    • 2004
  • A new reduction method of residual stress in welding joint is proposed where welded metals are shaken during welding. By an experiment using a small shaker, it can be shown that tensile residual stress near the bead is significantly reduced. Since tensile residual stress on the surface degrades fatigue strength for cumulative damage, the proposed method is effective to reduction of residual stress of welded joints. The effectiveness of the proposed method is demonstrated by the response analysis using one mass model with nonlinear springs.

Fatigue Characteristics of Load-Carrying-Cruciform-Fillet-Welded-Joints According to Welding Methods (용접방법에 따른 하중전달 십자형 필렛 용접부의 피로특성)

  • 이용복;오병덕
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.1
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    • pp.38-44
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    • 2003
  • In this study, endurance limit and fatigue behavior of load carrying fillet welded cruciform joints depending on commonly used welding methods such as SMAW, SAW, MIG and FCAW are investigated. In respect of endurance limit SMAW specimen showes highest result, and then MIG, SAW, FCAW in descending order. However, SMAW specimen showes lowest crack growth rate and it followed by MIG, FCAW, SAW. By these results, it is needed to use SMAW or MIG welding methods for welding structures with small welding capacity and SAW or FCAW methods for large welding structures with respect to economic benefits and operation efficiency of welding. It was also shown fatigue crack growth rate was more influenced by the strenght of welding materials than the endurance limit of welding materials.

FATIGUE STRENGTH OF FILLET WELDED STEEL STRUCTURE UNDER OUT-OF-PLANE BENDING LOAD

  • Kang, Sung-Won;Kim, Wha-Soo;Paik, Young-Min
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.113-120
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    • 2002
  • The effect of out-of-plane loads on the fatigue strength of welded steel structures is examined through fatigue tests with weldment of two fillet weld joint types. The results of the fatigue tests are compared with those under axial loads, on the basis of the hot spot stress range at the weld toe. From the result of the comparison, a method on how to incorporate the effect of the out-of-plane bending stress is proposed using design S-N curves derived from fatigue tests under the axial load. The proposed method is useful for rational assessment of the fatigue strength of fillet-welded structures, where combined stresses of the in-plane axial stress and the out-of-plane bending stress are induced simultaneously due to the complexity of applied loads and structural geometry.

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Effect of the welding residual stress redistribution on impact absorption energy (재분포된 용접잔류응력이 충격흡수에너지에 미치는 영향)

  • Yang, Zhaorui;Lee, Youngseog
    • Journal of Welding and Joining
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    • v.33 no.1
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    • pp.72-79
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    • 2015
  • Evaluation of fracture toughness of welded structures has a significant influence on the structural design. However the residual stresses is redistributed while the welded structures is cut for preparing specimens. This study investigated an effect of the welding residual stress redistribution on the impact absorption energy of Charpy specimen. SA516Gr70 steel plate by at the flux cored arc welding (FCAW) and gas tungsten arc welding(GTAW) was cutting. Specimens for Charpy impact testing were taken from the welded plate. Two material removal mechanisms (wire cutting and water jet) were used to make the specimens. Welding residual stress and redistribution residual stress were measured using the XRD (X-Ray Diffraction) method. The amount of redistribution of residual stress depends on the different material removal mechanism. Redistribution of residual stress of reduced the impact absorption energy by 15%.

A Study on the Fatigue Life Assessment for Load-carrying Fillet Welded Joints using Stress Intensity Factor (응력확대계수를 이용한 하중 전달형 필릿 용접부의 피로강도 평가에 관한 연구)

  • Kim, Myung-Hyun;Kang, Sung-Won;Kim, Hyoung-Rae
    • Journal of Welding and Joining
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    • v.26 no.6
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    • pp.97-102
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    • 2008
  • It is well known that there exist two typical fatigue crack initiation locations in ship structures: one is the weld toe and the other is the weld root where partial penetration weld is performed. In particular, it is important for fillet weldments to avoid weld root cracking in order to prevent catastrophic failure particularly in ship structures. Therefore detail considerations are required for cruciform joints with partial penetration when there is a possibility of weld root crack initiation. For these reasons, fatigue tests on welded joints were performed in this study. Concept of stress intensity factor(SIF) by means of fracture mechanics is applied for predicting fatigue life of fillet welded joints.

Fatigue Life Analysis of Butt-welded specimen by Local Strain Approach (국부변형률방법을 이용한 용접시험편의 피로수명 해석)

  • Lee Dong-Hyong;Seo Jung-Won;Goo Byeong-choon;Seok Chang-Sung
    • Proceedings of the KSR Conference
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    • 2003.10c
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    • pp.73-78
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    • 2003
  • The residual stresses and. distortions of structures by welding exert negative effect on the safety of railroad structures. This investigation performs a thermal elasto-plastic analysis using finite element techniques to evaluate residual stresses in butted-welded joint. Considering this initial residual stresses, local stress and strain at the critical location (weld toe) during the loading were analyzed by elastic plastic finite element analysis. Fatigue crack initiation life and fatigue crack propagation life of butt-welded specimen were predicted by local strain approach and Neuber's role and Paris law. It is demonstrated that fatigue life estimates by local strain approach closely approximate the experimental results.

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