The Experts below are selected from a list of 1629 Experts worldwide ranked by ideXlab platform
Russell Q Bridge - One of the best experts on this subject based on the ideXlab platform.
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the shape of Circumferential Weld induced imperfections in thin walled steel silos and tanks
Thin-walled Structures, 2001Co-Authors: Martin Pircher, P A Berry, Xiaoli Ding, Russell Q BridgeAbstract:The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, Circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during the erection of steel silos and tanks, specific types of imperfections are introduced into these structures, among them Circumferential Weld-induced imperfections between strakes of steel plates. The shape of such a localised Circumferential imperfection has been shown to have a great influence on the degree of strength loss of thin-walled cylindrical shell structures. The results of a survey of imperfections in an existing silo at a location in Port Kembla, Australia in combination with linear elastic shell bending theory was used to develop and calibrate a shape function which accurately describes the geometric features of Circumferential Weld imperfections. The proposed shape function is the first function to combine shell theory with actual field imperfection measurements. It is a continuous function and incorporates all the necessary features to represent the geometry of a Circumferential Weld-induced imperfection. It was found that after filtering out the effects of overall imperfections three parameters governed the shape of the surveyed imperfections: the depth, the wavelength and the roundness.
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the influence of Circumferential Weld induced imperfections on the buckling of silos and tanks
Journal of Constructional Steel Research, 2001Co-Authors: Martin Pircher, Russell Q BridgeAbstract:Abstract The load carrying behaviour of cylindrical thin-walled shell structures under axial load is strongly dependent on imperfections invariably caused by various manufacturing processes. Axisymmetric imperfections have been known to result in particularly severe reductions in strength. Imperfections in the vicinity of Circumferential Welds in steel silos and tanks fall into this category and therefore deserve special attention. A detailed bifurcation and post-buckling finite element analysis was performed on imperfect cylindrical shells. Special care was taken to model the Weld-induced Circumferential imperfection. The geometry was calibrated against data gained from measuring such imperfections on existing silos and residual stresses were taken into account. Interaction between neighbouring Weld imperfections and the role of the strake height in this interaction was investigated. Weld-induced residual stresses were found to have a small strengthening influence on the buckling load. Interaction between neighbouring imperfections was found to reduce the buckling strength of the structures. A post-buckling analysis was undertaken and an explanation of the load-carrying behaviour of the structure after initial bifurcation was given.
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Buckling of Thin-Walled Silos and Tanks under Axial Load—Some New Aspects
Journal of Structural Engineering, 2001Co-Authors: Martin Pircher, Russell Q BridgeAbstract:The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, Circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during the erection of steel silos and tanks, specific types of imperfections are introduced into these structures, among them Circumferential Weld-induced imperfections between strakes of steel plates. A study on several factors influencing the buckling of silos and tanks was carried out using the finite-element method. The interaction between neighboring Circumferential Weld imperfections was investigated, and it was found that the influence on the buckling behavior depended on the strake height in relation to the linear meridional bending half-wavelength and the depth of the imperfection. The shape of localized Circumferential Weld imperfections was found to influence the buckling behavior of silos and tanks. The influence of a recently developed shape function on the buckling behavior has been examined. The strengthening effect of Weld-induced residual stress fields was also studied, and the extent of the increase in buckling strength was derived for a large range of cylinder geometries.
Martin Pircher - One of the best experts on this subject based on the ideXlab platform.
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the shape of Circumferential Weld induced imperfections in thin walled steel silos and tanks
Thin-walled Structures, 2001Co-Authors: Martin Pircher, P A Berry, Xiaoli Ding, Russell Q BridgeAbstract:The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, Circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during the erection of steel silos and tanks, specific types of imperfections are introduced into these structures, among them Circumferential Weld-induced imperfections between strakes of steel plates. The shape of such a localised Circumferential imperfection has been shown to have a great influence on the degree of strength loss of thin-walled cylindrical shell structures. The results of a survey of imperfections in an existing silo at a location in Port Kembla, Australia in combination with linear elastic shell bending theory was used to develop and calibrate a shape function which accurately describes the geometric features of Circumferential Weld imperfections. The proposed shape function is the first function to combine shell theory with actual field imperfection measurements. It is a continuous function and incorporates all the necessary features to represent the geometry of a Circumferential Weld-induced imperfection. It was found that after filtering out the effects of overall imperfections three parameters governed the shape of the surveyed imperfections: the depth, the wavelength and the roundness.
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the influence of Circumferential Weld induced imperfections on the buckling of silos and tanks
Journal of Constructional Steel Research, 2001Co-Authors: Martin Pircher, Russell Q BridgeAbstract:Abstract The load carrying behaviour of cylindrical thin-walled shell structures under axial load is strongly dependent on imperfections invariably caused by various manufacturing processes. Axisymmetric imperfections have been known to result in particularly severe reductions in strength. Imperfections in the vicinity of Circumferential Welds in steel silos and tanks fall into this category and therefore deserve special attention. A detailed bifurcation and post-buckling finite element analysis was performed on imperfect cylindrical shells. Special care was taken to model the Weld-induced Circumferential imperfection. The geometry was calibrated against data gained from measuring such imperfections on existing silos and residual stresses were taken into account. Interaction between neighbouring Weld imperfections and the role of the strake height in this interaction was investigated. Weld-induced residual stresses were found to have a small strengthening influence on the buckling load. Interaction between neighbouring imperfections was found to reduce the buckling strength of the structures. A post-buckling analysis was undertaken and an explanation of the load-carrying behaviour of the structure after initial bifurcation was given.
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Buckling of Thin-Walled Silos and Tanks under Axial Load—Some New Aspects
Journal of Structural Engineering, 2001Co-Authors: Martin Pircher, Russell Q BridgeAbstract:The strength of thin-walled cylindrical shell structures is highly dependent on the nature and magnitude of imperfections. Most importantly, Circumferential imperfections have been reported to have an especially detrimental effect on the buckling resistance of these shells under axial load. Due to the manufacturing techniques commonly used during the erection of steel silos and tanks, specific types of imperfections are introduced into these structures, among them Circumferential Weld-induced imperfections between strakes of steel plates. A study on several factors influencing the buckling of silos and tanks was carried out using the finite-element method. The interaction between neighboring Circumferential Weld imperfections was investigated, and it was found that the influence on the buckling behavior depended on the strake height in relation to the linear meridional bending half-wavelength and the depth of the imperfection. The shape of localized Circumferential Weld imperfections was found to influence the buckling behavior of silos and tanks. The influence of a recently developed shape function on the buckling behavior has been examined. The strengthening effect of Weld-induced residual stress fields was also studied, and the extent of the increase in buckling strength was derived for a large range of cylinder geometries.
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The Influence of Circumferential Weld-induced Imperfections on the Buckling of Silos and Tanks
Advances in Steel Structures (ICASS '99), 1999Co-Authors: Martin PircherAbstract:Publisher Summary The load carrying behavior of cylindrical thin-walled shell structures under axial load is strongly dependent on imperfections invariably caused by various manufacturing processes. Axisymmetric imperfections have been recognized to result in particularly severe reductions in strength. Imperfections in the vicinity of Circumferential Welds in steel silos and tanks fall into this category. A detailed bifurcation and postbuckling finite element analysis was performed on imperfect cylindrical shells. Special care was taken to model the Weld-induced Circumferential imperfection. The geometry was calibrated against data gained from measuring such imperfections on existing silos and residual stresses were taken into account. Interactions between neighboring Weld imperfections and the role of the strake height in this interaction was investigated. Weld-induced residual stresses were found to have a small strengthening influence on the buckling load. Interaction between neighboring imperfections was found to reduce the buckling strength of the structures. A postbuckling analysis was undertaken to investigate the load-carrying behavior of the structure after initial bifurcation.
Yang Zhao - One of the best experts on this subject based on the ideXlab platform.
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Form of Circumferential Weld-induced imperfections for tapered-wall cylindrical shell structures
The IES Journal Part A: Civil & Structural Engineering, 2013Co-Authors: Zhen Wang, Yang ZhaoAbstract:Initial geometric imperfections have a great effect on the buckling strength of thin-walled cylindrical shells under axial compression, and the Circumferential Weld-induced imperfection is usually the most deleterious imperfection form. Two axisymmetric imperfection forms proposed by Rotter and Teng have widely been employed in the buckling analysis of cylindrical shells. However, the applicability of the two forms for tapered-wall cylinders needs further study, since they are derived from the elastic bending theory for long thin-walled cylinders with a constant wall thickness. This paper presents a modified form of Circumferential imperfection for tapered-wall cylinders. Finite element analyses are carried out by employing the trapezoidal strain field approach to model the Welding process, and the obtained Circumferential depression shapes are used to evaluate the availability of the modified imperfection form. It is shown that the modified imperfection form is reasonable for any wall thickness ratio bet...
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Buckling Strength of Tapered Cylindrical Shells under Partial Axial Compression: Effect of Circumferential Weld-Induced Imperfections
Advanced Materials Research, 2010Co-Authors: Zhen Wang, Yang ZhaoAbstract:Buckling is often the main design consideration for thin cylindrical shells. For most load cases, the stability behavior of the shell is acutely sensitive to Circumferential Weld-induced imperfections, and the corresponding residual stresses are some beneficial to buckling strength of the shell generally. However, these conclusions are all based on the cylinders with constant wall thickness, and the studies about the effect of residual stresses on buckling strength of tapered cylindrical shells under partial axial compression are few. This paper applies trapezoidal strain field approach to simulate Circumferential Weld-induced imperfections on tapered cylindrical shellls, and studies the stability behavior of the cylinders with single Circumferential Weld and multiple Circumferential Welds under partial axial compression respectively. By comparing the results derived from the models with/without Circumferential Welds and corresponding residual stresses, the effects of Weld depressions and residual stresses on tapered cylindrical shells under partial axial compression are obtained.
Zhen Wang - One of the best experts on this subject based on the ideXlab platform.
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Form of Circumferential Weld-induced imperfections for tapered-wall cylindrical shell structures
The IES Journal Part A: Civil & Structural Engineering, 2013Co-Authors: Zhen Wang, Yang ZhaoAbstract:Initial geometric imperfections have a great effect on the buckling strength of thin-walled cylindrical shells under axial compression, and the Circumferential Weld-induced imperfection is usually the most deleterious imperfection form. Two axisymmetric imperfection forms proposed by Rotter and Teng have widely been employed in the buckling analysis of cylindrical shells. However, the applicability of the two forms for tapered-wall cylinders needs further study, since they are derived from the elastic bending theory for long thin-walled cylinders with a constant wall thickness. This paper presents a modified form of Circumferential imperfection for tapered-wall cylinders. Finite element analyses are carried out by employing the trapezoidal strain field approach to model the Welding process, and the obtained Circumferential depression shapes are used to evaluate the availability of the modified imperfection form. It is shown that the modified imperfection form is reasonable for any wall thickness ratio bet...
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Buckling Strength of Tapered Cylindrical Shells under Partial Axial Compression: Effect of Circumferential Weld-Induced Imperfections
Advanced Materials Research, 2010Co-Authors: Zhen Wang, Yang ZhaoAbstract:Buckling is often the main design consideration for thin cylindrical shells. For most load cases, the stability behavior of the shell is acutely sensitive to Circumferential Weld-induced imperfections, and the corresponding residual stresses are some beneficial to buckling strength of the shell generally. However, these conclusions are all based on the cylinders with constant wall thickness, and the studies about the effect of residual stresses on buckling strength of tapered cylindrical shells under partial axial compression are few. This paper applies trapezoidal strain field approach to simulate Circumferential Weld-induced imperfections on tapered cylindrical shellls, and studies the stability behavior of the cylinders with single Circumferential Weld and multiple Circumferential Welds under partial axial compression respectively. By comparing the results derived from the models with/without Circumferential Welds and corresponding residual stresses, the effects of Weld depressions and residual stresses on tapered cylindrical shells under partial axial compression are obtained.
M.m.i. Hammouda - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Weld-induced residual stresses and distortions in thin-walled cylinders
Journal of Mechanical Science and Technology, 2009Co-Authors: Naeem Ullah Dar, Ejaz M. Qureshi, M.m.i. HammoudaAbstract:Circumferential Weld specifically in thin-walled structures is a common joint type in the fabrication of structural members in aerospace, aeronautical and pressure vessel industries. This type of Weld joint suffers various types of Weld-induced residual stress fields (hoop and axial) and deformation patterns (axial shrinkage, radial shrinkage). These imperfections have negative effects on fabrication accuracies and result in low strength Welded structures that can lead to premature failures. To precisely capture the distortions and residual stresses, computational methodology based on three-dimensional finite element model for the simulation of gas tungsten arc Welding in thin-walled cylinders is presented. Butt-Weld geometry with single “V” for a 300 mm outer diameter cylinder of 3 mm thick is used. The complex phenomenon of arc Welding is numerically solved by sequentially coupled transient, non-linear thermo-mechanical analysis. The accuracy of both the thermal and structural models is validated through experiments for temperature distribution, residual stresses and distortion. The simulated result shows close correlation with the experimental measurements.