The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Meneghetti G. - One of the best experts on this subject based on the ideXlab platform.
-
Austempered ductile iron-to-steel dissimilar arc-welded joints: fatigue Strength Assessment according to local approaches
'Elsevier BV', 2020Co-Authors: Meneghetti G., Campagnolo A., Pullin E., Masaggia S.Abstract:The design of mechanical components increasingly requires the adoption of different materials in the same structure with the aim of improving its performance. One of the available solutions is to adopt dissimilar arc-welded joints, which typically must withstand high fatigue loadings during in-service life. In a recent paper, the fatigue Strength of EN-JS-1050 austempered ductile iron-to-S355J2 steel dissimilar arc-welded joints was experimentally investigated by testing some typical welded details in the as-welded conditions, under either axial or four-point bending loadings. In the present work, previous experimental campaign has been extended by fatigue testing other ADI-to-steel joint details. The fracture surfaces of all tested joints have been analysed to identify the fatigue crack initiation locations. Then, experimental fatigue results have been re-analysed to determine the fatigue Strength category of each welded detail, which have been compared with those provided by International Standards for corresponding homogeneous steel joints. Afterwards, the local approach based on the Peak Stress Method (PSM) combined with the averaged Strain Energy Density (SED) fatigue criterion, has been used for the first time for fatigue Strength Assessment of ADI-to-steel dissimilar arc-welded joints. First, the structural volume size R0 has been calibrated for joints exhibiting fatigue crack initiation and propagation at the ADI side; then, a PSM-based fatigue design curve has been determined by fitting the available experimental results
-
Experimental tests and fatigue Strength Assessment of a scotch yoke valve actuator
'Elsevier BV', 2018Co-Authors: Bergonzoni Matteo, Campagnolo A., Pellinghelli D., Riboli M., Spagnoli A., Meneghetti G.Abstract:Aim of this work is the fatigue Assessment of a main component of a valve actuator used for oil & gas, power and chemical industries, in order to comply with its heavy-duty applications. To do this, full-scale valve actuator assemblies made of S355J2 steel have been fatigue tested under nominal axial loading. All specimens have been tested under stress-relieved conditions by adopting a nominal load ratio R=-1. After experimental tests, the fatigue crack paths have been analysed by means of liquid penetrant inspections. The fatigue Strength class of the considered yoke has been determined by statistically re-analysing the experimental results, expressed in terms of range of the nominal applied load, and it has been compared with the design condition required by the relevant European Standard, EN 15714-3/4. Finally, two methodologies for fatigue Strength Assessment of the considered scotch yokes have been proposed, which are based on experimental fatigue data derived from smooth or sharp V-notched specimens, respectively, made of the same yoke material. The Assessment capability of the proposed methodologies has been evaluated and discussed by comparing theoretical estimations with the experimental fatigue results of the scotch yokes
-
Experimental tests and fatigue Strength Assessment of a scotch yoke valve actuator
'Elsevier BV', 2018Co-Authors: Bergonzoni M., Campagnolo A., Pellinghelli D., Riboli M., Spagnoli A., Meneghetti G.Abstract:Aim of this work is the fatigue Assessment of a main component, termed scotch yoke, of a valve actuator used for oil & gas, power and chemical industries, in order to comply with its heavy-duty applications. To do this, full-scale specimens of the scotch yoke made of structural steel have been fatigue tested under nominal axial loading. All specimens have been tested under stress-relieved conditions by adopting a nominal load ratio R=-1. After experimental tests, the fatigue crack paths have been analysed by means of liquid penetrant inspections. The fatigue Strength class of the considered scotch yoke has been determined by statistically re-analysing the experimental results, expressed in terms of range of the nominal applied load, and it has been compared with the design condition required by the relevant European Standard, EN 15714-3/4. Finally, two methodologies for fatigue Strength Assessment of the considered scotch yokes have been proposed, which are based on experimental fatigue data derived from smooth or sharp V-notched specimens, respectively, made of the same yoke material. The Assessment capability of the proposed methodologies has been evaluated and discussed by comparing theoretical estimations with the experimental fatigue results of the scotch yokes
J Kodvanj - One of the best experts on this subject based on the ideXlab platform.
-
tensile Strength Assessment of corroded small scale specimens
Corrosion Science, 2014Co-Authors: Yordan Garbatov, Guedes C Soares, Joško Parunov, J KodvanjAbstract:Tensile Strength tests are performed on small scale corroded specimens, so as to derive their mechanical properties. The specimens were cut from a box girder that was initially corroded in real sea water conditions. As a result of the tensile tests the mechanical properties of the specimens are determined, namely modulus of elasticity, yield stress, tensile Strength, resilience, fracture toughness and total uniform elongation. Regression equations are derived for the properties as a function of the degree of corrosion degradation. It is identified that those material parameters are influenced by the severity of corrosion degradation.
Guedes C Soares - One of the best experts on this subject based on the ideXlab platform.
-
Strength Assessment of an intact and damaged container ship subjected to asymmetrical bending loadings
Marine Structures, 2018Co-Authors: M Tekgoz, Yordan Garbatov, Guedes C SoaresAbstract:Abstract The objective of this work is to analyse the effect of structural damage and associated neutral axis translation and rotation of the residual load carrying capacity of a container ship hull subjected to asymmetrical bending loading. The Assessment is performed by a finite element analysis (FEA) and a formulation based on the Common Structural Rules (CSR). A container ship is analysed in intact and damaged conditions. The position of the neutral axis of the mid-ship section of the container ship is identified at each load step based on FEA and CSR. An update to the progressive collapse approach stipulated by CSR is proposed and compared with the finite element solution. Finally, some conclusions are presented.
-
fast approach for ultimate Strength Assessment of steel box girders subjected to non uniform corrosion degradation
Corrosion Engineering Science and Technology, 2016Co-Authors: S Saadeldeen, Yordan Garbatov, Guedes C SoaresAbstract:The present paper assesses the ultimate bending moment of steel box girders subjected to intensive non-uniform corrosion degradation. A comparison between the experimental results of three corroded box girders and different existing formulations has been performed. The moment–curvature relationship for the three corroded box girders has been calculated using the Common Structural Rules iterative process and the finite element method, leading to a development of corrosion scale factors to account for both geometrical and mechanical properties changes. Based on the experimental results, a relationship has been developed to calculate the equivalent Young's modulus of corroded structures as a function of the total reduction in cross-sectional area. A systematic procedure for the application of the newly developed fast approach and the new equivalent Young's modulus has been presented that can be used for any ultimate bending moment–curvature calculation tools.
-
tensile Strength Assessment of corroded small scale specimens
Corrosion Science, 2014Co-Authors: Yordan Garbatov, Guedes C Soares, Joško Parunov, J KodvanjAbstract:Tensile Strength tests are performed on small scale corroded specimens, so as to derive their mechanical properties. The specimens were cut from a box girder that was initially corroded in real sea water conditions. As a result of the tensile tests the mechanical properties of the specimens are determined, namely modulus of elasticity, yield stress, tensile Strength, resilience, fracture toughness and total uniform elongation. Regression equations are derived for the properties as a function of the degree of corrosion degradation. It is identified that those material parameters are influenced by the severity of corrosion degradation.
-
Strength Assessment of a severely corroded box girder subjected to bending moment
Journal of Constructional Steel Research, 2014Co-Authors: S Saadeldeen, Yordan Garbatov, Guedes C SoaresAbstract:Abstract This work deals with the evaluation of the ultimate bending moment of a severely corroded box girder subjected to uniform vertical bending moment through a series of nonlinear finite element analysis. Two models of corrosion degradation have been adopted, one is an average general corrosion thickness reduction, and the other is the real thickness of the corroded plates. New stress–strain relations have been developed to account for the effect of corrosion on the flexural rigidity. To validate the new developed stress–strain relationships, a comparison between the finite element analysis results using the existing stress–strain models, the newly developed ones and the experimental test results of a severely corroded box girder have been conducted. The comparison showed a good agreement and supported the choice of the newly developed stress–strain relationships of corroded structures.
-
ultimate Strength Assessment of rectangular steel plates subjected to a random localised corrosion degradation
Engineering Structures, 2013Co-Authors: J Silva, Y Garbatov, Guedes C SoaresAbstract:Abstract The objective of the present study is to investigate the effects of a random corrosion thickness distribution on the ultimate Strength of unstiffened rectangular steel plates subjected to uniaxial compressive load. Two new and distinct corrosion surface models are proposed and investigated. A total of 3575 corroded plate surface geometries are generated by Monte Carlo simulation for different degrees of degradation, location and ages and non-linear finite element analyses are carried out, using a finite element code. Based on a regression analysis, empirical formulae to predict Strength reduction due to corrosion have been derived demonstrating a good accuracy.
Yordan Garbatov - One of the best experts on this subject based on the ideXlab platform.
-
Strength Assessment of an intact and damaged container ship subjected to asymmetrical bending loadings
Marine Structures, 2018Co-Authors: M Tekgoz, Yordan Garbatov, Guedes C SoaresAbstract:Abstract The objective of this work is to analyse the effect of structural damage and associated neutral axis translation and rotation of the residual load carrying capacity of a container ship hull subjected to asymmetrical bending loading. The Assessment is performed by a finite element analysis (FEA) and a formulation based on the Common Structural Rules (CSR). A container ship is analysed in intact and damaged conditions. The position of the neutral axis of the mid-ship section of the container ship is identified at each load step based on FEA and CSR. An update to the progressive collapse approach stipulated by CSR is proposed and compared with the finite element solution. Finally, some conclusions are presented.
-
fast approach for ultimate Strength Assessment of steel box girders subjected to non uniform corrosion degradation
Corrosion Engineering Science and Technology, 2016Co-Authors: S Saadeldeen, Yordan Garbatov, Guedes C SoaresAbstract:The present paper assesses the ultimate bending moment of steel box girders subjected to intensive non-uniform corrosion degradation. A comparison between the experimental results of three corroded box girders and different existing formulations has been performed. The moment–curvature relationship for the three corroded box girders has been calculated using the Common Structural Rules iterative process and the finite element method, leading to a development of corrosion scale factors to account for both geometrical and mechanical properties changes. Based on the experimental results, a relationship has been developed to calculate the equivalent Young's modulus of corroded structures as a function of the total reduction in cross-sectional area. A systematic procedure for the application of the newly developed fast approach and the new equivalent Young's modulus has been presented that can be used for any ultimate bending moment–curvature calculation tools.
-
tensile Strength Assessment of corroded small scale specimens
Corrosion Science, 2014Co-Authors: Yordan Garbatov, Guedes C Soares, Joško Parunov, J KodvanjAbstract:Tensile Strength tests are performed on small scale corroded specimens, so as to derive their mechanical properties. The specimens were cut from a box girder that was initially corroded in real sea water conditions. As a result of the tensile tests the mechanical properties of the specimens are determined, namely modulus of elasticity, yield stress, tensile Strength, resilience, fracture toughness and total uniform elongation. Regression equations are derived for the properties as a function of the degree of corrosion degradation. It is identified that those material parameters are influenced by the severity of corrosion degradation.
-
Strength Assessment of a severely corroded box girder subjected to bending moment
Journal of Constructional Steel Research, 2014Co-Authors: S Saadeldeen, Yordan Garbatov, Guedes C SoaresAbstract:Abstract This work deals with the evaluation of the ultimate bending moment of a severely corroded box girder subjected to uniform vertical bending moment through a series of nonlinear finite element analysis. Two models of corrosion degradation have been adopted, one is an average general corrosion thickness reduction, and the other is the real thickness of the corroded plates. New stress–strain relations have been developed to account for the effect of corrosion on the flexural rigidity. To validate the new developed stress–strain relationships, a comparison between the finite element analysis results using the existing stress–strain models, the newly developed ones and the experimental test results of a severely corroded box girder have been conducted. The comparison showed a good agreement and supported the choice of the newly developed stress–strain relationships of corroded structures.
Jani Romanoff - One of the best experts on this subject based on the ideXlab platform.
-
fatigue Strength analysis of laser hybrid welds in thin plate considering weld geometry in microscale
International Journal of Fatigue, 2016Co-Authors: Sami Liinalampi, Heikki Remes, Jani Romanoff, Pauli Lehto, Ingrit Lillemae, David PorterAbstract:Abstract Utilization of thin plates together with laser-based welding processes allows manufacturing of large weight efficient steel structures. However, the fatigue Strength of welds in thin-plate structures with plate thicknesses below 5 mm is observed to have large variation, which brings challenges to fatigue Strength Assessment. One possible reason for this variation is the increased influence of actual weld geometry that is neglected in common fatigue Strength Assessment approaches utilizing geometry idealization. To reveal this influence the fatigue Strength of 3 mm thick laser-hybrid welded butt joints were studied using the measured microscale weld geometry and the notch stress approach. Notch stresses were defined using Neuber’s stress averaging approach which allows the determination of the fatigue-effective stress without fictitious geometric modifications. For the studied specimens the large scatter of fatigue Strength in the high-cycle region could be explained using this approach with high-resolution weld profile measurements combined with thorough finite-element analysis. It was observed that axial misalignment in narrow laser-hybrid welds causes a significant notch stress increase on the root side reducing the fatigue Strength dramatically in terms of structural and nominal stress. In order to capture the increased notch stress it is crucial to use a significantly smaller stress averaging length than commonly assumed for welded joints.
-
j integral based approach to fatigue Assessment of laser stake welded t joints
International Journal of Fatigue, 2013Co-Authors: Darko Frank, Heikki Remes, Jani Romanoff, Heikki Remes, Jani RomanoffAbstract:Abstract The aim of this paper is to investigate the influence of the plate thickness on the fatigue Strength of laser stake-welded T-joints under the tension loading condition. Fatigue tests were conducted on specimens with plate thicknesses below 5 mm subjected to tension loading with the load ratio R = 0. The statistical analysis of the weld geometry showed a normal distribution of the each parameter that was measured. In addition, the parameters had similar proportions in comparison to the specimens with plate thicknesses above 5 mm. FE analysis was performed with the aim of determining the stress state in the joint along with the J-integral. If the square root of the J-integral, √ΔJ, is used as the fatigue Strength Assessment parameter, the fatigue Strength obtained at five million cycles is similar as in the case of other steel welded joint types. The investigation concluded that the stress state changes with the reduction of the plate thicknesses and the contribution of fracture mode II becomes significant. However, using √ΔJ as a fatigue Strength Assessment parameter ensures that the complex state of the mixed fracture mode loading is accurately accounted for. This fact further enables the fatigue Strength of laser stake-welded T-joints of any plate thicknesses to be described by means of a narrower scatterband than the one obtained by the nominal stress approach.
