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Effects of Welding Residual Stress on Compressive Behavior and Ultimate Strength of Corroded Plate
Abstract
This study examined the effects of welding residual stress on the compressive behavior and the ultimate strength of the corroded
plate. First, welding residual stress was obtained by the thermal elastic-plastic analysis. Then, the change of welding residual
stress and the deflection due to the volume loss was investigated by using a newly developed program based on FEM. Finally,
the effects of welding residual stress on the compressive behavior and the ultimate strength of the corroded plate were investigated
by the elastic-plastic large deformation analysis. As results, the beginning point of the reduction of the initial stiffness
with welding residual stress was earlier than that without welding residual stress. Such effect was observed significantly
in the case that the volume was lost in the region which has compressive residual stress. Furthermore, the ultimate strength
of the corroded plate was reduced by welding residual stress regardless of the plate length, the corroded regions and the
reduction of the thickness. The effect of welding residual stress on the ultimate strength became small with the decrease
of the thickness.
... On cooling, locally shrinkage and residual tensile stresses, up to the yield stress are generated in these areas, while in adjacent areas residual compressive stresses occur to maintain equilibrium. In terms of corrosion effect studies, only [97,81] applied the welding residual stresses to models of stiffened panels and plating respectively, under uniaxial compressive loading. Corrosion features were located in areas with either compressive or tensile residual stress. ...
... Dunbar et al. [97] concluded that corrosion in the region of tensile residual stress mainly reduced the post-ultimate strength and would raise the buckling strength when corrosion occurs in the compression region. Tamagawa and Kim reported that the ultimate strength would be reduced by residual stresses regardless of the corrosion parameters [81]. But the reduction diminished when the thickness reduction due to corrosion becomes significant. ...
... Both work rebalanced the equilibrium condition after applying corrosion damage using different approaches. Moreover, Tamagawa and Kim [81] also updated the predefined geometric imperfection to satisfy the equilibrium. However, the welding effect has been ignored in most of the work. ...
The state-of-the-art in modelling the influence of corrosion damage on the ultimate strength of aged steel-plated maritime platforms is reviewed. This critical review outlines the corrosion mechanisms and fundamentals of steel-plated structures in the marine environment. Recent developments in mathematical modelling strategies, in association with in situ thickness measurements, have significantly enhanced the qualitative understanding of the corrosion processes at various locations within marine structures. Based on the corrosion prediction, both experimental and numerical methods have been adopted to realistically assess the ultimate strength of such corroded steel ship structures, in order to ultimately improve the survey and repair strategies.
... Tenga et al. [9] investigated the influence of welding sequence on residual stress and the optimum welding sequence was derived. Tamagawa and Kim [10] studied the mechanical behavior of steel plate under compression, but the symmetry hypothesis was adopted and only a quarter of the steel plate was built. This may bring error for the welding residual stress is not in completely symmetrical distribution due the error happens during real welding process, even though the structure is symmetrical. ...
Investigation of welding residual stress on the mechanical behavior of the entire structures is a very difficult work to do due to the amazing computational resource required. It is very necessary to access the influence of welding residual stress on mechanical behavior of absolute welding structures, buckling behavior especially. The residual stress will decrease the component stiffness and then the critical load of the entire structures. In this paper, a method was proposed to access the influence of welding residual stress on the entire structure and was adopted to calculate its influence on buckling behavior of a practical absolute welding structure. The results indicate that the welding residual stress has significant influence on buckling behavior of the structure. The method proposed in this paper is the foundation of further study on influence of welding residual stress.
... Generally, initial deflections are introduced in form of the half sine wave in both orthogonal directions of the interior web panels. However, in the stiffener and free end of the web, it is provided as quarter of the sine wave in transversal direction, and half sine wave in longitudinal direction by using the expression given in Equation (2) (Dunbar, Pegg, Taheric, & Jianga, 2004;Tamagawa & Kim, 2010). In this study, the initial deflections were incorporated by using the scaled deformations from the elastic buckling (eigenvalue) analysis as used by many other researchers (Choi, Hwanga, Yoona, & Yoo, 2009). ...
Many field surveys depict that steel plate girder ends tend to corrode due to the leakage of water from construction joints and/or detention of rain water near bearing regions. In many cases, buckling failures of plate girders were observed due to the excessive loss of material at the bottom portion of bearing stiffeners. In this study, the effect on the buckling strength of steel plate girder due to the corrosion damage at bearing stiffeners was investigated. Full-scale experimental tests were performed on two plate girder ends to determine the bearing capacity. Bearing capacity and failure modes were also verified by numerical analyses. Initial imperfections and welding residual stresses were also taken into account in analytical models. The simulation of the model was extended to the various corrosion damages, considering different damaged heights and thicknesses of the bearing stiffener near weld seam. All results were plotted in terms of remaining bearing capacity versus damage thickness ratio keeping the damage height of the stiffener constant. In this study, a damage parameter Reduced Thickness Ratio was used to assess the ultimate capacity and buckling of steel plate girder end with various corrosion levels.
Because of its characteristics of good rigidity and strong ant-vibration, heavy-duty welding turning tools are widely applied in the rough machining of water chamber heads. However, welding residual stress is induced around the welding seam of the tool. During the heavy-duty machining, cracks easily occur due to an influence of impacts, high-temperature and thermal-mechanical loading, which causes tools failure. In this paper, ANSYS finite element model of heavy-duty cutting tools is established based on thermal elastic-plastic theory in order to analyze thermal stress field distribution in welding process. Secondly, actual welding residual stress distribution is obtained by the nano indentation experiment, verifying that the model can effectively analyze the stress and strain distribution. The welding tool failure mechanism is explored further. Finally, vibration aging and ultrasonic impact treatment methods are adopted to reduce welding residual stress of heavy-duty cutting tools. Two methods are compared for the influence of welding residual stress. Through the above research, finite element model can exactly reflect the welding residual stress distribution. The ultrasonic impact treatment is better than vibration aging treatment to reduce the welding residual stress and then extend their service life.
Most existing studies on the vibration analysis of cylindrical shells with structural stress are limited to uniform stress distribution. However, non-uniform stress distributions are encountered in many engineering applications. In this study, a unified solution for the vibration analysis of cylindrical shells with a general stress distribution is presented using the Flügge shell theory and modal orthogonality simplification. The obtained analytical solution can be applied to a structure with arbitrary distributed stress, thus it has a wider range of applications than previous methods. The accuracy and advantage of the proposed method are validated by comparing with the finite element method results.
Detailed numerical investigation on the mechanical behavior of welded box member was conducted by applying welding residual stress as initial load. The temperature field was first derived and the result was used as body load for elastic–plastic mechanical analysis. Distribution law of welding residual stress was derived based on models in different scales. Results derived from different models were then compared. Residual stress was used as initial stress by conducting secondary development of finite element software ANSYS, and the influence of welding residual stress on mechanical behavior of box members was derived. Finally, parametrical analysis was conducted to investigate the influence of weld-induced deformation on mechanical behavior of box member and the sensitivity of box members consisting of steel plates with different thickness. The ultimate load bearing capacity under compression and bending moment decreased along with the increase of the amplitude of weld-induced deformation. Torsional capacity was almost unaffected by the amplitude of weld-induced deformation. Results presented in this study established the basis for studying the influence of welding residual stress on the entire structure.
In this study, two methods, X-ray diffraction (nondestructive) and hole-drilling (destructive) are applied to measure the residual stress of gas metal arc welded steel plate. Both non-relaxed and relaxed (local heating, furnace annealing and bead blasting) weldments are examined to understand the residual stress distributions before and after elimination of residual stresses. Results show that the heat affected zone of gas metal arc welding method is about 10 mm from the weld centerline. The local heating method is very effective in reducing the residual stress caused by the cold work of the original steel plate. The furnace annealing method reduces the residual stress to compressive but not uniformly distributed. The detrimental fluctuation of residual stress is successfully reduced and uniformly relaxed to be beneficially compressive in the bead blasting. Most importantly, X-ray diffraction shows more precise and better handling than hole-drilling method in terms of data error. © 2016, Korean Society of Steel Construction and Springer-Verlag Berlin Heidelberg.
FEM analysis is a useful method of estimating the ultimate strength of damaged structures by corrosion. Actually, a large number of studies have been made on the ultimate strength of these structures by use of FEM analysis. However, most of them neglected effects of a redistribution of residual stress or dead load stress caused by volume change due to corrosion.This paper develops a finite element method that estimate the ultimate strength of corroded steel structures, and proposes a shell element that takes into consideration the change of mechanical behavior caused by volume change due to corrosion. Moreover, the effects of redistribution of residual stress or dead load stress on the ultimate strength of a steel plate are shown.
腐食は鋼橋における損傷の中でも最も一般的なものであり, 橋梁を架け替える際の重要な要因の一つとなっている. また, 今後, 既設橋梁を健全な状態に保持していくためには, 腐食に関して, その点検から補修補強に至る一連の維持管理手法を確立しておくことが重要である. このような観点から, 本研究では, 鋼道路橋を管理する技術者に腐食に関する情報をわかりやすい形で提供することを目的として, これまでに報告されている腐食事例や実橋調査結果を収集・整理し, 鋼橋のどのような部位に, どのようなことが原因で腐食が生じるのかを整理分析した. また, 点検に際しての留意点や効率的な点検を実施するための重要点検部位を示すとともに, 腐食を検出するための非破壊検査手法に関しても提案した.
The loss of material due to corrosion sometimes has a large influence on the change of weld residual. stresses and residual deflections of steel structures. A new finite-element method is proposed that can take into account the effects of the volume change of material. By the use of this new method, it is expected that the change of weld residual stresses and residual deflections due to loss of material can be evaluated, if only the distributions of the residual stresses and residual deflections at the initial state as well as the corrosion profiles are known in advance. In order to confirm the validity of the proposed method, an experiment is carried out to measure the change of weld residual stresses and residual deflections by mechanically forming a groove on the surface of a welded steel box column that mimics a local corrosion loss pattern. From the experiment, it is observed that the change of the weld residual stresses and residual deflections caused by the groove is well predicted by the proposed analysis method as long as the corresponding initial values of the box column without groove are known in advance.
The necessity of assessing the durability of structures such as bridges and offshore structures has arisen recently. It is obvious that the maintenance of infrastructures has become a key issue to assure the desired performance in operational condition and to prolong the life of structures. As for the life cycle performance of the steel elements in the marine atmosphere, in particular, the damage due to corrosion is important rather than that by fatigue. Investigated herein is the effect of the surface profile of corroded steel plates on the compressive strength by the elasto-plactic finite displacement analysis, by using the ficticious surface profile as well as the surface profile measured for the corroded steel pipes subjected to the corrosion exposure in the field under severer marine environment for about 20 years. The simple strength evaluation is proposed by considering the plate thickness variation in the smallest cross section.
Treatment of welding imperfection in elastic-plastic large deformation analysis for elucidating compressive behavior of butt-welded plate
- Y C Kim
- M Hirohata
- D H Park
- Y. C. Kim
Prediction of welding distortion and residual stress by idealization of welding and its accuracy-In the case of butt welding
- Y C Kim
- J Y Lee
- M Sawada
- K Inose
- Y. C. Kim
Specifications for highway bridges Part1 Common Part
- Japan Road Association
Development and application of a finite element analysis based on shell element considering a redistribution of stress caused by corrosion
- S Tamagawa
- T Miyoshi
- S. Tamagawa