Pub Date : 2022-10-24DOI: 10.1108/ijsi-08-2022-0108
Vikas Sharma, J. P. Misra, S. Singhal
PurposeIn the present study, wire electro-spark machining of Titanium alloy is performed with the machining parameter such as spark-on time, spark-off time, current and servo voltage. The purpose of this study is to model surface roughness using machine learning approach for input/controllable variable. Machined surface examined using scanning electron microscope (SEM) and XRD methods.Design/methodology/approachFull factorial approach has been used to design the experiments with varying machining parameters into three-level four factors. Obtained surface roughness was modeled using machine learning methods namely Gaussian process regression (GPR) and support vector machine (SVM) methods. These methods were compared for both training and testing data with a coefficient of correlation and root mean square error basis. Machined surface examined using scanned electron microscopy and XRD for surface quality produced and check migration of tool material to workpiece material.FindingsMachine learning algorithms has excellent scope for prediction quality response for the wire electric discharge machining (WEDM) process, resulting in saving of time and cost as it is difficult to find each time experimentally. It has been found that the proposed model with minimum computational time, provides better solution and avoids priority weightage calculation by decision-makers.Originality/valueThe proposed modeling provides better predication about surface produced while machining of Ti6Al7Nb using zinc-coated brass wire electrode during WEDM operation.
{"title":"Surface roughness modeling using machine learning approaches for wire electro-spark machining of titanium alloy","authors":"Vikas Sharma, J. P. Misra, S. Singhal","doi":"10.1108/ijsi-08-2022-0108","DOIUrl":"https://doi.org/10.1108/ijsi-08-2022-0108","url":null,"abstract":"PurposeIn the present study, wire electro-spark machining of Titanium alloy is performed with the machining parameter such as spark-on time, spark-off time, current and servo voltage. The purpose of this study is to model surface roughness using machine learning approach for input/controllable variable. Machined surface examined using scanning electron microscope (SEM) and XRD methods.Design/methodology/approachFull factorial approach has been used to design the experiments with varying machining parameters into three-level four factors. Obtained surface roughness was modeled using machine learning methods namely Gaussian process regression (GPR) and support vector machine (SVM) methods. These methods were compared for both training and testing data with a coefficient of correlation and root mean square error basis. Machined surface examined using scanned electron microscopy and XRD for surface quality produced and check migration of tool material to workpiece material.FindingsMachine learning algorithms has excellent scope for prediction quality response for the wire electric discharge machining (WEDM) process, resulting in saving of time and cost as it is difficult to find each time experimentally. It has been found that the proposed model with minimum computational time, provides better solution and avoids priority weightage calculation by decision-makers.Originality/valueThe proposed modeling provides better predication about surface produced while machining of Ti6Al7Nb using zinc-coated brass wire electrode during WEDM operation.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42236950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-19DOI: 10.1108/ijsi-05-2022-0070
Jiafeng Lai, Yu-Hsing Wang, Yuwei Wei, Jinlu Liang, Xintian Liu
PurposeThe purpose of the paper is to predict the residual life of liquid-storage tank to ensure safety and long-term service life of the structure.Design/methodology/approachThe paper carried out the stress analysis of the wall plate and bottom plate of the liquid-storage tank, and the influence of circumferential stress on the tank is considered. On the other hand, considering the influence of the tank wall surface on the tank life, based on the Paris law, the surface processing coefficient and surface roughness coefficient are introduced to improve the Paris law.FindingsThe effectiveness of the improved model is verified by comparing with theoretical and experimental data, which provide a new method for the prediction of the remaining service life of the tank. Combined with the fatigue crack data in the test report and the calculated circumferential stress, the residual life of the storage tank is predicted.Originality/valueThe improved model provides a new method for the prediction of the remaining service life of the tank.
{"title":"The prediction of residual life of liquid-storage tank considering the tank wall surface state","authors":"Jiafeng Lai, Yu-Hsing Wang, Yuwei Wei, Jinlu Liang, Xintian Liu","doi":"10.1108/ijsi-05-2022-0070","DOIUrl":"https://doi.org/10.1108/ijsi-05-2022-0070","url":null,"abstract":"PurposeThe purpose of the paper is to predict the residual life of liquid-storage tank to ensure safety and long-term service life of the structure.Design/methodology/approachThe paper carried out the stress analysis of the wall plate and bottom plate of the liquid-storage tank, and the influence of circumferential stress on the tank is considered. On the other hand, considering the influence of the tank wall surface on the tank life, based on the Paris law, the surface processing coefficient and surface roughness coefficient are introduced to improve the Paris law.FindingsThe effectiveness of the improved model is verified by comparing with theoretical and experimental data, which provide a new method for the prediction of the remaining service life of the tank. Combined with the fatigue crack data in the test report and the calculated circumferential stress, the residual life of the storage tank is predicted.Originality/valueThe improved model provides a new method for the prediction of the remaining service life of the tank.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49313539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-18DOI: 10.1108/ijsi-04-2022-0063
J. Henriques, J. Xavier, A. Andrade-Campos
PurposeThis work aims to identify the linear elastic orthotropic material paramters of Pinus pinaster Ait. wood, using full-field measurements and an inverse identification strategy based on the finite element (FE) method updating technique.Design/methodology/approachCompression tests are carried out under uniaxial and quasi-static loading conditions on wood specimens oriented on the radial-tangential (RT) plane, with different grain orientations. Full-field displacements and strains are measured using digital image correlation (DIC), which are then used as a reference in the identification procedure. A FE model is implemented assuming plane stress conditions, where wood is modelled as an orthotropic homogeneous material. Based on the numerical results, a synthetic image reconstruction scheme is implemented to synthetically deform the reference experimental image, which is then processed by DIC and further compared to the experimental results.FindingsThe results for both approaches were similar when both specimen configurations were used in a single run. However, when using the DIC-based FEMU approach with the on-axis configuration, the identified modulus of elasticity in the tangential direction and shear modulus are closer to the reference values.Originality/valueThis approach ensures a fair comparison between both sets of data since the full-field strain maps are obtained through the same filter and therefore have the same strain formulation, spatial resolution and data filtering. Firstly, the identification is performed using a single configuration, either the on-axis or the off-axis specimen. Secondly, the identification is carried out by merging data from both on-axis and off-axis configurations.
{"title":"On the inverse identification of wood elastic properties using a DIC-based FEMU approach","authors":"J. Henriques, J. Xavier, A. Andrade-Campos","doi":"10.1108/ijsi-04-2022-0063","DOIUrl":"https://doi.org/10.1108/ijsi-04-2022-0063","url":null,"abstract":"PurposeThis work aims to identify the linear elastic orthotropic material paramters of Pinus pinaster Ait. wood, using full-field measurements and an inverse identification strategy based on the finite element (FE) method updating technique.Design/methodology/approachCompression tests are carried out under uniaxial and quasi-static loading conditions on wood specimens oriented on the radial-tangential (RT) plane, with different grain orientations. Full-field displacements and strains are measured using digital image correlation (DIC), which are then used as a reference in the identification procedure. A FE model is implemented assuming plane stress conditions, where wood is modelled as an orthotropic homogeneous material. Based on the numerical results, a synthetic image reconstruction scheme is implemented to synthetically deform the reference experimental image, which is then processed by DIC and further compared to the experimental results.FindingsThe results for both approaches were similar when both specimen configurations were used in a single run. However, when using the DIC-based FEMU approach with the on-axis configuration, the identified modulus of elasticity in the tangential direction and shear modulus are closer to the reference values.Originality/valueThis approach ensures a fair comparison between both sets of data since the full-field strain maps are obtained through the same filter and therefore have the same strain formulation, spatial resolution and data filtering. Firstly, the identification is performed using a single configuration, either the on-axis or the off-axis specimen. Secondly, the identification is carried out by merging data from both on-axis and off-axis configurations.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47708226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-14DOI: 10.1108/ijsi-06-2022-0081
F. H. Øyasæter, A. Aeran, S. Siriwardane
PurposeSeveral experimental and numerical studies were performed in the past to estimate buckling capacity of corroded tubular members. However, the effect of initial imperfections has not been properly considered in most of these earlier proposed formulas. Therefore, the main objective of this paper is to propose an accurate analytical formula to determine the buckling capacity of patched corroded tubular members.Design/methodology/approachTubular members with initial geometrical imperfections can be regarded as beam-columns because of the combination of axial load and bending moment. The proposed formula is derived for a rectangular corrosion patch. The proposed formula is verified with results from finite element analysis of corroded tubular members and experimental results. The formula is also applied to an existing offshore jacket structure to highlight its significance and applicability. It is found that the buckling capacity of jacket members in splash zone reduces significantly with ageing. This reduction is around 29 and 14% for the selected brace and leg member respectively, during the design life. Finally, it is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers to give an accurate and slightly conservative estimate the remaining buckling capacity.FindingsThe main finding is the new formula which accurately and conservatively estimate the buckling capacity of corroded tubular members. The proposed formula considers the secondary effect of both initial geometrical imperfections and shifting of centroid because of corrosion.Originality/valueThe proposed new formula is unique and original in that it considers both secondary effects from geometrical imperfections, reduction of cross-section from corrosion wastage and shifting of centroid because of corrosion. Finally, it is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers to conservatively estimate the remaining buckling capacity and verify if further, more advanced estimations are needed.
{"title":"A formula for estimating the buckling capacity of corroded tubular members","authors":"F. H. Øyasæter, A. Aeran, S. Siriwardane","doi":"10.1108/ijsi-06-2022-0081","DOIUrl":"https://doi.org/10.1108/ijsi-06-2022-0081","url":null,"abstract":"PurposeSeveral experimental and numerical studies were performed in the past to estimate buckling capacity of corroded tubular members. However, the effect of initial imperfections has not been properly considered in most of these earlier proposed formulas. Therefore, the main objective of this paper is to propose an accurate analytical formula to determine the buckling capacity of patched corroded tubular members.Design/methodology/approachTubular members with initial geometrical imperfections can be regarded as beam-columns because of the combination of axial load and bending moment. The proposed formula is derived for a rectangular corrosion patch. The proposed formula is verified with results from finite element analysis of corroded tubular members and experimental results. The formula is also applied to an existing offshore jacket structure to highlight its significance and applicability. It is found that the buckling capacity of jacket members in splash zone reduces significantly with ageing. This reduction is around 29 and 14% for the selected brace and leg member respectively, during the design life. Finally, it is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers to give an accurate and slightly conservative estimate the remaining buckling capacity.FindingsThe main finding is the new formula which accurately and conservatively estimate the buckling capacity of corroded tubular members. The proposed formula considers the secondary effect of both initial geometrical imperfections and shifting of centroid because of corrosion.Originality/valueThe proposed new formula is unique and original in that it considers both secondary effects from geometrical imperfections, reduction of cross-section from corrosion wastage and shifting of centroid because of corrosion. Finally, it is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers to conservatively estimate the remaining buckling capacity and verify if further, more advanced estimations are needed.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42684740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-11DOI: 10.1108/ijsi-04-2022-0056
O. Staroverov, D. Lobanov, E. Strungar, E. Lunegova
PurposeThe main purpose of this study was to evaluate the mechanical behaviour of layered fibrous carbon-fibre reinforced plastic (CFRP) under complex low-speed bending and impact loads and subsequent cyclic tensile loads.Design/methodology/approachA comprehensive approach was adopted to study the damage accumulation processes using state-of-the-art testing and diagnostic equipment. In the course of the study, a microstructure analysis of damages caused by a transverse impact and cyclic tension was performed.FindingsA dependence of residual fatigue life of the studied composite material on the intensity of the preliminary impact bending was established. Temperature field distribution fields on the surface of the sample during tests were shown. Data on damage accumulation processes were presented, which were obtained during the registration of acoustic emission signals.Originality/valueA connection was established between changes of registered acoustic response signals and thermal imaging camera data, which was supported by the results of an experimental study. The results of the comprehensive approach showed a qualitative correlation.
{"title":"Evaluation of the influence of preliminary low-velocity impacts on the residual fatigue life of CFRP composites","authors":"O. Staroverov, D. Lobanov, E. Strungar, E. Lunegova","doi":"10.1108/ijsi-04-2022-0056","DOIUrl":"https://doi.org/10.1108/ijsi-04-2022-0056","url":null,"abstract":"PurposeThe main purpose of this study was to evaluate the mechanical behaviour of layered fibrous carbon-fibre reinforced plastic (CFRP) under complex low-speed bending and impact loads and subsequent cyclic tensile loads.Design/methodology/approachA comprehensive approach was adopted to study the damage accumulation processes using state-of-the-art testing and diagnostic equipment. In the course of the study, a microstructure analysis of damages caused by a transverse impact and cyclic tension was performed.FindingsA dependence of residual fatigue life of the studied composite material on the intensity of the preliminary impact bending was established. Temperature field distribution fields on the surface of the sample during tests were shown. Data on damage accumulation processes were presented, which were obtained during the registration of acoustic emission signals.Originality/valueA connection was established between changes of registered acoustic response signals and thermal imaging camera data, which was supported by the results of an experimental study. The results of the comprehensive approach showed a qualitative correlation.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46394445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-04DOI: 10.1108/ijsi-07-2022-0094
M. Labibzadeh, Farhad Bostan Shirin, A. Khajehdezfuly
PurposeThis study aims to investigate the effects of using circular spirals as the longitudinal reinforcing bars on the performance of the concrete beams subjected to four-point bending load.Design/methodology/approachThe effects of using circular spirals as the longitudinal reinforcing bars on the performance of the concrete beams subjected to four-point bending load are investigated in this study. Employing circular spirals as the main longitudinal reinforcement is a novel idea presented in this paper. In this regard, a finite element model of the beam with spiral longitudinal reinforcement was developed. After model verification, several configurations of concrete beams reinforced by longitudinal spirals were simulated under the four-point loading condition.FindingsObtained results showed that using the longitudinal spirals in place of the conventional longitudinal reinforcing bars can improve the bearing capacity of the concrete beam, but at the same time, increases its ductility unacceptably. In other words, the spirals reduce the initial stiffness of the beam significantly. To solve the problem, the authors decided to use the longitudinal spirals as the auxiliary bars added to the main conventional longitudinal bars in the beams. New gained results were satisfactory. By adding the longitudinal spirals to the conventional bars, not only the bearing capacity of the beam increases between 24% and 63%, but also the initial stiffness and ductility of the beam raises between 11%–29% and 3%–57%, respectively, in comparison to the corresponding beam reinforced with conventional longitudinal bars.Originality/valueEmploying circular spirals as the main longitudinal reinforcement is a novel idea presented in this paper.
{"title":"Improvement of performance of the RC beams using the longitudinal spiral reinforcements","authors":"M. Labibzadeh, Farhad Bostan Shirin, A. Khajehdezfuly","doi":"10.1108/ijsi-07-2022-0094","DOIUrl":"https://doi.org/10.1108/ijsi-07-2022-0094","url":null,"abstract":"PurposeThis study aims to investigate the effects of using circular spirals as the longitudinal reinforcing bars on the performance of the concrete beams subjected to four-point bending load.Design/methodology/approachThe effects of using circular spirals as the longitudinal reinforcing bars on the performance of the concrete beams subjected to four-point bending load are investigated in this study. Employing circular spirals as the main longitudinal reinforcement is a novel idea presented in this paper. In this regard, a finite element model of the beam with spiral longitudinal reinforcement was developed. After model verification, several configurations of concrete beams reinforced by longitudinal spirals were simulated under the four-point loading condition.FindingsObtained results showed that using the longitudinal spirals in place of the conventional longitudinal reinforcing bars can improve the bearing capacity of the concrete beam, but at the same time, increases its ductility unacceptably. In other words, the spirals reduce the initial stiffness of the beam significantly. To solve the problem, the authors decided to use the longitudinal spirals as the auxiliary bars added to the main conventional longitudinal bars in the beams. New gained results were satisfactory. By adding the longitudinal spirals to the conventional bars, not only the bearing capacity of the beam increases between 24% and 63%, but also the initial stiffness and ductility of the beam raises between 11%–29% and 3%–57%, respectively, in comparison to the corresponding beam reinforced with conventional longitudinal bars.Originality/valueEmploying circular spirals as the main longitudinal reinforcement is a novel idea presented in this paper.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45287399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-23DOI: 10.1108/ijsi-07-2022-0100
Solomon O. Obadimu, K. Kourousis
PurposeThe material extrusion (ME) process induces variations in the final part’s microscopic and macroscopic structural characteristics. This viewpoint article aims to uncover the relation between ME fabrication parameters and the microstructural and mesostructural characteristics of the ME BASF Ultrafuse Steel 316L metal parts. These characteristics can affect the structural integrity of the produced parts and components used in various engineering applications.Design/methodology/approachRecent studies on the ME BASF Ultrafuse Steel 316L are reviewed, with a focus on those which report microstructural and mesostructural characteristics that may affect structural integrity.FindingsA relationship between ME fabrication parameters and subsequent microstructural and mesostructural characteristics is discussed. Common microstructural and mesostructural/macrostructural defects are also highlighted and discussed.Originality/valueThis viewpoint article attempts to bridge the existing gap in the literature, highlighting the influence of ME fabrication parameters on Steel 316L parts fabricated via this additive manufacturing method. Moreover, this article identifies and discusses important considerations for the purposes of selecting and optimising the structural integrity of ME-fabricated Steel 316L parts.
{"title":"Microscopic and mesoscopic/macroscopic structural characteristics of material extrusion Steel 316L: influence of the fabrication process","authors":"Solomon O. Obadimu, K. Kourousis","doi":"10.1108/ijsi-07-2022-0100","DOIUrl":"https://doi.org/10.1108/ijsi-07-2022-0100","url":null,"abstract":"PurposeThe material extrusion (ME) process induces variations in the final part’s microscopic and macroscopic structural characteristics. This viewpoint article aims to uncover the relation between ME fabrication parameters and the microstructural and mesostructural characteristics of the ME BASF Ultrafuse Steel 316L metal parts. These characteristics can affect the structural integrity of the produced parts and components used in various engineering applications.Design/methodology/approachRecent studies on the ME BASF Ultrafuse Steel 316L are reviewed, with a focus on those which report microstructural and mesostructural characteristics that may affect structural integrity.FindingsA relationship between ME fabrication parameters and subsequent microstructural and mesostructural characteristics is discussed. Common microstructural and mesostructural/macrostructural defects are also highlighted and discussed.Originality/valueThis viewpoint article attempts to bridge the existing gap in the literature, highlighting the influence of ME fabrication parameters on Steel 316L parts fabricated via this additive manufacturing method. Moreover, this article identifies and discusses important considerations for the purposes of selecting and optimising the structural integrity of ME-fabricated Steel 316L parts.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46695594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-07DOI: 10.1108/ijsi-03-2022-0045
Paulo Silva Lobo, Mariana Jesus, Paulo S.A. Freitas
PurposeIn this paper a model for the prediction of the failure strain of fiber reinforced polymer (FRP) sheets is proposed, based on a significant database consisting of results reported in the literature for concrete columns with circular cross-section confined with carbon, glass and aramid fiber reinforced polymers. This study aims to analyze the aforementioned model.Design/methodology/approachSignificant experimental research on the confinement of columns externally wrapped with FRP has been carried out in the last decades. Several models of confined concrete have been proposed using different approaches for the prediction of the failure strain of FRP sheets. The majority of those proposals were developed to be simple, thus significant differences with experimental results can be found.FindingsThe results of a total of 572 specimens were considered. Statistical analysis was used to derive a regression model, which relates the outcome to a set of predictors of interest using linear assumptions.Originality/valueThe proposed model is shown to be more accurate than other proposals found in the literature.
{"title":"Prediction of the failure strain of FRP sheets on confined concrete columns with circular cross-section","authors":"Paulo Silva Lobo, Mariana Jesus, Paulo S.A. Freitas","doi":"10.1108/ijsi-03-2022-0045","DOIUrl":"https://doi.org/10.1108/ijsi-03-2022-0045","url":null,"abstract":"PurposeIn this paper a model for the prediction of the failure strain of fiber reinforced polymer (FRP) sheets is proposed, based on a significant database consisting of results reported in the literature for concrete columns with circular cross-section confined with carbon, glass and aramid fiber reinforced polymers. This study aims to analyze the aforementioned model.Design/methodology/approachSignificant experimental research on the confinement of columns externally wrapped with FRP has been carried out in the last decades. Several models of confined concrete have been proposed using different approaches for the prediction of the failure strain of FRP sheets. The majority of those proposals were developed to be simple, thus significant differences with experimental results can be found.FindingsThe results of a total of 572 specimens were considered. Statistical analysis was used to derive a regression model, which relates the outcome to a set of predictors of interest using linear assumptions.Originality/valueThe proposed model is shown to be more accurate than other proposals found in the literature.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47798618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-31DOI: 10.1108/ijsi-07-2022-0095
Yingbao He, Jianhui Liu, Feilong Hua, He Zhao, Jie Wang
PurposeUnder multiaxial random loading, the material stress–strain response is not periodic, which makes it difficult to determine the direction of the critical plane on the material. Meanwhile, existing methods of constant loading cannot be directly applied to multiaxial random loading; this problem can be solved when an equivalent stress transformation method is used.Design/methodology/approachFirst, the Liu-Mahadevan critical plane is introduced into multiaxial random fatigue, which is enabled to determine the material's critical plane position under random loading. Then, an equivalent stress transformation method is proposed which can convert random load to constant load. Meanwhile, the ratio of mean stress to yield strength is defined as the new mean stress influence factor, and a new non-proportional additional strengthening factor is proposed by considering the effect of phase differences.FindingsThe proposed model is validated using multiaxial random fatigue test data of TC4 titanium alloy specimens and the results of the proposed model are compared with that based on Miner's rule and BSW model, showing that the proposed method is more accurate.Originality/valueIn this work, a new multiaxial random fatigue life prediction model is proposed based on equivalent stress transformation method, which considers the mean stress effect and the additional strengthening effect. Results show that the predicted fatigue lives given by the proposed model are in well accordance with the tested data.
{"title":"Low-cycle multiaxial random fatigue life prediction model based on equivalent stress transformation","authors":"Yingbao He, Jianhui Liu, Feilong Hua, He Zhao, Jie Wang","doi":"10.1108/ijsi-07-2022-0095","DOIUrl":"https://doi.org/10.1108/ijsi-07-2022-0095","url":null,"abstract":"PurposeUnder multiaxial random loading, the material stress–strain response is not periodic, which makes it difficult to determine the direction of the critical plane on the material. Meanwhile, existing methods of constant loading cannot be directly applied to multiaxial random loading; this problem can be solved when an equivalent stress transformation method is used.Design/methodology/approachFirst, the Liu-Mahadevan critical plane is introduced into multiaxial random fatigue, which is enabled to determine the material's critical plane position under random loading. Then, an equivalent stress transformation method is proposed which can convert random load to constant load. Meanwhile, the ratio of mean stress to yield strength is defined as the new mean stress influence factor, and a new non-proportional additional strengthening factor is proposed by considering the effect of phase differences.FindingsThe proposed model is validated using multiaxial random fatigue test data of TC4 titanium alloy specimens and the results of the proposed model are compared with that based on Miner's rule and BSW model, showing that the proposed method is more accurate.Originality/valueIn this work, a new multiaxial random fatigue life prediction model is proposed based on equivalent stress transformation method, which considers the mean stress effect and the additional strengthening effect. Results show that the predicted fatigue lives given by the proposed model are in well accordance with the tested data.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48442047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-30DOI: 10.1108/ijsi-05-2022-0064
G. Narayanan
PurposeThe front bearing mount structure in an aero engine has been severely loaded under the fan blade off (FBO) event since imbalance forces at high amplitude but low frequency is transformed to the engine front mount structure. The bearing mount structural forces are estimated by an integrated implicit-explicit analysis process of whole engine model of an aero engine. Since there are many dependent factors which are governing those predicted loads, experimental evidence on FBO is becoming necessary to validate the model used for the load prediction which is more expensive and also time consuming. This paper aims to discuss the above mentioned issues.Design/methodology/approachThe current paper deals with the high impact but low probability nature of FBO load prediction on the bearing mount structure by stochastic approach which could be replaced for FBO experiments which is highly essential for current economic conditions. Several influential factors on the predicted loads have been chosen in the stochastic model and sensitive analysis has also been performed to bring down the variation involved in the predicted load.FindingsThe predicted load by proposed stochastic model is then compared with the experimental results. The conclusion on the predicted load with various dependent influential factors is matching well with certain value of damage factor from planned FBO test event.Research limitations/implicationsLimitation of this paper could be that it does not cover with range of load amplitude and is only applicable for civil small and medium engines.Practical implicationsThe high amplitude but low frequency load pattern is assessed with impact condition by stochastic model.Originality/valueCombining experimental and probabilistic load prediction was never done before and read across from previous engine test program could be effectively performed with stochastic model approach.
{"title":"Probabilistic method for impact load estimation by Stochastic Model – a Fan Blade Off event","authors":"G. Narayanan","doi":"10.1108/ijsi-05-2022-0064","DOIUrl":"https://doi.org/10.1108/ijsi-05-2022-0064","url":null,"abstract":"PurposeThe front bearing mount structure in an aero engine has been severely loaded under the fan blade off (FBO) event since imbalance forces at high amplitude but low frequency is transformed to the engine front mount structure. The bearing mount structural forces are estimated by an integrated implicit-explicit analysis process of whole engine model of an aero engine. Since there are many dependent factors which are governing those predicted loads, experimental evidence on FBO is becoming necessary to validate the model used for the load prediction which is more expensive and also time consuming. This paper aims to discuss the above mentioned issues.Design/methodology/approachThe current paper deals with the high impact but low probability nature of FBO load prediction on the bearing mount structure by stochastic approach which could be replaced for FBO experiments which is highly essential for current economic conditions. Several influential factors on the predicted loads have been chosen in the stochastic model and sensitive analysis has also been performed to bring down the variation involved in the predicted load.FindingsThe predicted load by proposed stochastic model is then compared with the experimental results. The conclusion on the predicted load with various dependent influential factors is matching well with certain value of damage factor from planned FBO test event.Research limitations/implicationsLimitation of this paper could be that it does not cover with range of load amplitude and is only applicable for civil small and medium engines.Practical implicationsThe high amplitude but low frequency load pattern is assessed with impact condition by stochastic model.Originality/valueCombining experimental and probabilistic load prediction was never done before and read across from previous engine test program could be effectively performed with stochastic model approach.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43618710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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