Pub Date : 2022-06-07DOI: 10.1108/ijsi-04-2022-0061
F. Bjørheim, D. Pavlou, S. Siriwardane
PurposeBrinell, Vickers and low-force Vickers hardness measurements are herein adopted to investigate and quantify the fatigue damage evolution in specimens made of S355J2+AR ferritic pearlitic steel. Though nano and microhardness measurements have been well adopted, they require a strict preparation routine, whereas macroscopic hardness measurements are not as stringent.Design/methodology/approachThe feasibility of adopting macroscopic hardness measurements as a means of measuring fatigue damage is investigated through a combination of experimental tests and finite element analyses with both Brinell and Vickers hardness indenter.FindingsIt is found that the Brinell hardness measurements method seems more feasible, regarding finding a continuous and significant change during the fatigue life, in comparison to both Vickers and low-force Vickers. Thereafter, the question regarding the feasibility of the hardness measurements as a method of assessing accumulated fatigue damage in situ is discussed.Originality/valueMuch work has previously been performed towards correlation of the micro and nano hardness indentations, which generally has stringent preparation requirements before testing. Herein, the adoption of macroscopic hardness measurements as a means of assessing accumulated fatigue damage is considered both experimentally and theoretically.
{"title":"Hardness measurements as a technique for measuring accumulated fatigue damage","authors":"F. Bjørheim, D. Pavlou, S. Siriwardane","doi":"10.1108/ijsi-04-2022-0061","DOIUrl":"https://doi.org/10.1108/ijsi-04-2022-0061","url":null,"abstract":"PurposeBrinell, Vickers and low-force Vickers hardness measurements are herein adopted to investigate and quantify the fatigue damage evolution in specimens made of S355J2+AR ferritic pearlitic steel. Though nano and microhardness measurements have been well adopted, they require a strict preparation routine, whereas macroscopic hardness measurements are not as stringent.Design/methodology/approachThe feasibility of adopting macroscopic hardness measurements as a means of measuring fatigue damage is investigated through a combination of experimental tests and finite element analyses with both Brinell and Vickers hardness indenter.FindingsIt is found that the Brinell hardness measurements method seems more feasible, regarding finding a continuous and significant change during the fatigue life, in comparison to both Vickers and low-force Vickers. Thereafter, the question regarding the feasibility of the hardness measurements as a method of assessing accumulated fatigue damage in situ is discussed.Originality/valueMuch work has previously been performed towards correlation of the micro and nano hardness indentations, which generally has stringent preparation requirements before testing. Herein, the adoption of macroscopic hardness measurements as a means of assessing accumulated fatigue damage is considered both experimentally and theoretically.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41588680","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 : 2022-05-23DOI: 10.1108/ijsi-02-2022-0015
G. Alabbadi, Rabab Allouzi
PurposeThe purpose of this study is to improve the lateral capacity of Cold-Formed Steel (CFS) frame walls filled with lightweight foamed concrete (LFC) and supported with straw boards by introducing structural foamed concrete and/or bracing.Design/methodology/approachFinite element models are developed and calibrated based on previous experimental work. Then, these models are extended to conduct a parametric study to quantify the effect of filling CFS walls and structural LFC and the effect of supporting CFS walls with bracing.FindingsResults of the study conclude that the finite element analysis can be used to simulate and analyze the lateral capacity of CFS walls effectively since the maximum deviation between calibrated and experimental results is 10%. The structural LFC usage in CFS walls improves the lateral capacity considerably by (25–75) % depending on the wall properties. Besides, the application of lateral bracing does not always have a positive effect on the lateral performance of these walls.Originality/valueAlthough CFS walls are preferred due to it is light in weight, low in cost, easy to install and recyclable, low seismic performance, buckling vulnerability, poor thermal insulation and sound insulation properties, low lateral stiffness, and low shear strength limit their use. This study proposes the use of structural foamed concrete and a different bracing method than what is available in the literature. This can overcome the drawbacks of the CFS walls alone which can permit the usage of such walls in mid-rise buildings and other applications.
{"title":"Finite element analysis of lateral response of lightweight foamed concrete-filled cold-formed steel walls","authors":"G. Alabbadi, Rabab Allouzi","doi":"10.1108/ijsi-02-2022-0015","DOIUrl":"https://doi.org/10.1108/ijsi-02-2022-0015","url":null,"abstract":"PurposeThe purpose of this study is to improve the lateral capacity of Cold-Formed Steel (CFS) frame walls filled with lightweight foamed concrete (LFC) and supported with straw boards by introducing structural foamed concrete and/or bracing.Design/methodology/approachFinite element models are developed and calibrated based on previous experimental work. Then, these models are extended to conduct a parametric study to quantify the effect of filling CFS walls and structural LFC and the effect of supporting CFS walls with bracing.FindingsResults of the study conclude that the finite element analysis can be used to simulate and analyze the lateral capacity of CFS walls effectively since the maximum deviation between calibrated and experimental results is 10%. The structural LFC usage in CFS walls improves the lateral capacity considerably by (25–75) % depending on the wall properties. Besides, the application of lateral bracing does not always have a positive effect on the lateral performance of these walls.Originality/valueAlthough CFS walls are preferred due to it is light in weight, low in cost, easy to install and recyclable, low seismic performance, buckling vulnerability, poor thermal insulation and sound insulation properties, low lateral stiffness, and low shear strength limit their use. This study proposes the use of structural foamed concrete and a different bracing method than what is available in the literature. This can overcome the drawbacks of the CFS walls alone which can permit the usage of such walls in mid-rise buildings and other applications.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42862087","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 : 2022-05-10DOI: 10.1108/ijsi-03-2022-0023
Muzhou Ma, Xintian Liu
PurposeA large number of data have proved that under the same von Mises equivalent strain condition, the fatigue life under multiaxial non-proportional loading is often much lower than the life under multiaxial proportional loading. This is mainly due to the influence of the non-proportional loading path and the additional hardening effect, which lead to a sharp decrease in life.Design/methodology/approachThe modulus attenuation effect is used to modify the static hardening coefficient, and the predicted value obtained is closer to the additional hardening coefficient obtained from the experiment. A fatigue life model can consider non-proportional paths, and additional hardening effects are proposed. And the model uses multiaxial fatigue test data to verify the validity and adaptability of the new model. The life prediction accuracy and material application range are satisfactory.FindingsBecause loading path and additional hardening of the material affect fatigue life, a new multiaxis fatigue life model based on the critical plane approach is proposed. And introducing a non-proportional additional damage coefficient, the joint influence of the load path and the additional hardening can be considered. The model's life prediction accuracy and material applicability were verified with multiaxial fatigue test data of eight materials and nine loads compared with the prediction accuracy of the Kandil–Brown–Miller (KBM) model and Fatemi–Socie (FS) model.Originality/valueThe physical meaning of the new model is clear, convenient for practical engineering applications.
{"title":"Multiaxial fatigue life prediction for metallic materials considering loading path and additional hardening effect","authors":"Muzhou Ma, Xintian Liu","doi":"10.1108/ijsi-03-2022-0023","DOIUrl":"https://doi.org/10.1108/ijsi-03-2022-0023","url":null,"abstract":"PurposeA large number of data have proved that under the same von Mises equivalent strain condition, the fatigue life under multiaxial non-proportional loading is often much lower than the life under multiaxial proportional loading. This is mainly due to the influence of the non-proportional loading path and the additional hardening effect, which lead to a sharp decrease in life.Design/methodology/approachThe modulus attenuation effect is used to modify the static hardening coefficient, and the predicted value obtained is closer to the additional hardening coefficient obtained from the experiment. A fatigue life model can consider non-proportional paths, and additional hardening effects are proposed. And the model uses multiaxial fatigue test data to verify the validity and adaptability of the new model. The life prediction accuracy and material application range are satisfactory.FindingsBecause loading path and additional hardening of the material affect fatigue life, a new multiaxis fatigue life model based on the critical plane approach is proposed. And introducing a non-proportional additional damage coefficient, the joint influence of the load path and the additional hardening can be considered. The model's life prediction accuracy and material applicability were verified with multiaxial fatigue test data of eight materials and nine loads compared with the prediction accuracy of the Kandil–Brown–Miller (KBM) model and Fatemi–Socie (FS) model.Originality/valueThe physical meaning of the new model is clear, convenient for practical engineering applications.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47092228","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 : 2022-05-09DOI: 10.1108/ijsi-03-2022-0039
Erfan Najaf, H. Abbasi, S. M. Zahrai
PurposeToday, using lightweight structural concrete plays a major role in reducing the damage to concrete structures. On the other hand, lightweight concretes have lower compressive and flexural strengths with lower impact resistance compared to ordinary concretes. The aim of this study is to investigate the effect of simultaneous use of waste glass powder, microsilica and polypropylene fibers to make sustainable lightweight concrete that has high compressive and flexural strengths, ductility and impact resistance.Design/methodology/approachIn this article, the lightweight structural concrete is studied to compensate for the lower strength of lightweight concrete. Also, considering the environmental aspects, microsilica as a partial replacement for cement, waste glass powder instead of some aggregates and polypropylene fibers are used. Microsilica was used at 8, 10 and 12 wt% of cement. Waste glass powder was added to 20, 25 and 30 wt% of aggregates, while fibers were used at 0.5, 1 and 1.5 wt% of cement.FindingsAfter making the experimental specimens, compressive strength, flexural strength and impact resistance tests were performed. Ultimately, it was concluded that the best percentage of used microsilica and glass powder was equal to 10 and 25%, respectively. Furthermore, using 1.5 wt% of fibers could significantly improve the compressive and flexural strengths of lightweight concrete and increase its impact resistance at the same time. For constructing a five-story building, by replacing cement with microsilica by 10 wt%, the amount of used cement is reduced by 5 tons, consequently producing 4,752 kg less CO2 that is a significant value for the environment.Originality/valueThe study provides a basis for making sustainable lightweight concrete with high strength against compressive, flexural and impact loads.
{"title":"Effect of waste glass powder, microsilica and polypropylene fibers on ductility, flexural and impact strengths of lightweight concrete","authors":"Erfan Najaf, H. Abbasi, S. M. Zahrai","doi":"10.1108/ijsi-03-2022-0039","DOIUrl":"https://doi.org/10.1108/ijsi-03-2022-0039","url":null,"abstract":"PurposeToday, using lightweight structural concrete plays a major role in reducing the damage to concrete structures. On the other hand, lightweight concretes have lower compressive and flexural strengths with lower impact resistance compared to ordinary concretes. The aim of this study is to investigate the effect of simultaneous use of waste glass powder, microsilica and polypropylene fibers to make sustainable lightweight concrete that has high compressive and flexural strengths, ductility and impact resistance.Design/methodology/approachIn this article, the lightweight structural concrete is studied to compensate for the lower strength of lightweight concrete. Also, considering the environmental aspects, microsilica as a partial replacement for cement, waste glass powder instead of some aggregates and polypropylene fibers are used. Microsilica was used at 8, 10 and 12 wt% of cement. Waste glass powder was added to 20, 25 and 30 wt% of aggregates, while fibers were used at 0.5, 1 and 1.5 wt% of cement.FindingsAfter making the experimental specimens, compressive strength, flexural strength and impact resistance tests were performed. Ultimately, it was concluded that the best percentage of used microsilica and glass powder was equal to 10 and 25%, respectively. Furthermore, using 1.5 wt% of fibers could significantly improve the compressive and flexural strengths of lightweight concrete and increase its impact resistance at the same time. For constructing a five-story building, by replacing cement with microsilica by 10 wt%, the amount of used cement is reduced by 5 tons, consequently producing 4,752 kg less CO2 that is a significant value for the environment.Originality/valueThe study provides a basis for making sustainable lightweight concrete with high strength against compressive, flexural and impact loads.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43616233","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 : 2022-04-22DOI: 10.1108/ijsi-12-2021-0133
Yan Liang, Yingying Wei, Panjie Li, Huan Niu, Jingxiao Shu
PurposeAlthough mechanical behavior of rigid frame pier has been clearly recognized, their time-varying seismic performance are yet to be well characterized due to some offshore piers that are eroded by chloride ion and located in earthquake-prone area. In this study, the time-variant seismic fragility analysis was conducted to evaluate seismic performance of rigid frame pier under four damage states with considering the time-varying characteristics of the material.Design/methodology/approachThis paper establishes the nonlinear finite element model for the investigated offshore reinforcement concrete (RC) pier with considering the time-varying durability damage of the materials and defines the damage state, damage position and damaged index of the offshore RC pier. It also analyzes the time-varying seismic fragility of the offshore RC pier by using the capacity demand ratio method in the whole life cycle.FindingsThe results show that chloride induced corrosion has a significant effect on the rigid frame pier and bending capacity of top section is less than that of bottom section. The rate of decline accelerates after the service life reaching 30 years under the coupling of the earthquake and the environmental erosion. In the early years of service, the seismic fragility of the structure changed slowly.Originality/valueThis paper analyzes the influencing factors of seismic performance of rigid structure pier, and analyzes the seismic capacity and seismic performance of rigid structure pier under different service periods.
{"title":"Analysis of time-varying seismic fragility of rigid frame pier of offshore bridge","authors":"Yan Liang, Yingying Wei, Panjie Li, Huan Niu, Jingxiao Shu","doi":"10.1108/ijsi-12-2021-0133","DOIUrl":"https://doi.org/10.1108/ijsi-12-2021-0133","url":null,"abstract":"PurposeAlthough mechanical behavior of rigid frame pier has been clearly recognized, their time-varying seismic performance are yet to be well characterized due to some offshore piers that are eroded by chloride ion and located in earthquake-prone area. In this study, the time-variant seismic fragility analysis was conducted to evaluate seismic performance of rigid frame pier under four damage states with considering the time-varying characteristics of the material.Design/methodology/approachThis paper establishes the nonlinear finite element model for the investigated offshore reinforcement concrete (RC) pier with considering the time-varying durability damage of the materials and defines the damage state, damage position and damaged index of the offshore RC pier. It also analyzes the time-varying seismic fragility of the offshore RC pier by using the capacity demand ratio method in the whole life cycle.FindingsThe results show that chloride induced corrosion has a significant effect on the rigid frame pier and bending capacity of top section is less than that of bottom section. The rate of decline accelerates after the service life reaching 30 years under the coupling of the earthquake and the environmental erosion. In the early years of service, the seismic fragility of the structure changed slowly.Originality/valueThis paper analyzes the influencing factors of seismic performance of rigid structure pier, and analyzes the seismic capacity and seismic performance of rigid structure pier under different service periods.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44585182","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 : 2022-04-19DOI: 10.1108/ijsi-01-2022-0008
V. Pranay, S. Panigrahi
PurposeThe purpose of this study is to design and develop new spiral head projectiles undergoing ballistics impact.Design/methodology/approachThe introduction of the rifled barrel in firearms made projectile spin during its flight path. The central translational velocity (impact velocity) is one parameter to defeat/penetrate the target in the penetration process. Another important parameter considered to be the shape of the projectile. Many types of projectile shapes have been designed to defeat the target. In the recent years, ogival nose shape is one of the well-known projectile shapes in use abundantly. The present research is made to design the nose shape so as to use the spin during the penetration of target effectively. In this study, a new spiral head projectile shape is proposed and designed, which uses the rotation of projectile (spin) for penetrating the Al7075-T6 target. When the ogive and new spiral head projectile is impacted on Al 7075-T6 target of 12.5 mm, 18 mm thicknesses at ordnance velocities, the residual velocity is evaluated numerically using ANSYS/Explicit Dynamics at normal impact condition. Two projectile materials, steel 4340 and tungsten alloy, are used as projectile materials. Along with the translational velocity, rotation velocities (spin rate) 13,000, 26,000 and 52,000 rad/s also provided to projectile. The residual velocities verses spin rate are plotted for different spiral angle projectiles for impact velocities 1,000–1,500 m/s, at normal impact conditions on the Al 7075-T6 target. Compared with the ogive nose projectile, the proposed new spiral head projectile made of tungsten alloy is significantly effective.FindingsSpiral head projectile having tungsten alloy material gives encouraging results at 12.5 mm target thickness. The new spiral head projectile is damaged partially. At 18 mm target thickness impact conditions, it is observed that the projectile head is completely damaged. The effectiveness of spiral head projectile on a target plate thickness of 18 mm is considered to study the impact condition.Research limitations/implicationsAll the above results need to be experimentally verified. However, the basic numerical model used in the present study, i.e. the basic ogive nose numerical model with only translational energy, is well validated with penetration theory available in literatures.Practical implicationsThe designed new spiral head projectile is only effective with tungsten alloy material within considered design parameters. For steel 4340 material, the spiral head projectile is less effective than the ogive nose projectile. In tungsten alloy projectiles, by observing all considered spiral angles, 30-degree spiral angle projectile gives the best performance at most of the considered impact velocity conditions.Originality/valueThe proposed research outputs are original, innovative and, have lot of importance in defence applications particularly in arms and ammunitions.
{"title":"Design and development of new spiral head projectiles undergoing ballistics impact","authors":"V. Pranay, S. Panigrahi","doi":"10.1108/ijsi-01-2022-0008","DOIUrl":"https://doi.org/10.1108/ijsi-01-2022-0008","url":null,"abstract":"PurposeThe purpose of this study is to design and develop new spiral head projectiles undergoing ballistics impact.Design/methodology/approachThe introduction of the rifled barrel in firearms made projectile spin during its flight path. The central translational velocity (impact velocity) is one parameter to defeat/penetrate the target in the penetration process. Another important parameter considered to be the shape of the projectile. Many types of projectile shapes have been designed to defeat the target. In the recent years, ogival nose shape is one of the well-known projectile shapes in use abundantly. The present research is made to design the nose shape so as to use the spin during the penetration of target effectively. In this study, a new spiral head projectile shape is proposed and designed, which uses the rotation of projectile (spin) for penetrating the Al7075-T6 target. When the ogive and new spiral head projectile is impacted on Al 7075-T6 target of 12.5 mm, 18 mm thicknesses at ordnance velocities, the residual velocity is evaluated numerically using ANSYS/Explicit Dynamics at normal impact condition. Two projectile materials, steel 4340 and tungsten alloy, are used as projectile materials. Along with the translational velocity, rotation velocities (spin rate) 13,000, 26,000 and 52,000 rad/s also provided to projectile. The residual velocities verses spin rate are plotted for different spiral angle projectiles for impact velocities 1,000–1,500 m/s, at normal impact conditions on the Al 7075-T6 target. Compared with the ogive nose projectile, the proposed new spiral head projectile made of tungsten alloy is significantly effective.FindingsSpiral head projectile having tungsten alloy material gives encouraging results at 12.5 mm target thickness. The new spiral head projectile is damaged partially. At 18 mm target thickness impact conditions, it is observed that the projectile head is completely damaged. The effectiveness of spiral head projectile on a target plate thickness of 18 mm is considered to study the impact condition.Research limitations/implicationsAll the above results need to be experimentally verified. However, the basic numerical model used in the present study, i.e. the basic ogive nose numerical model with only translational energy, is well validated with penetration theory available in literatures.Practical implicationsThe designed new spiral head projectile is only effective with tungsten alloy material within considered design parameters. For steel 4340 material, the spiral head projectile is less effective than the ogive nose projectile. In tungsten alloy projectiles, by observing all considered spiral angles, 30-degree spiral angle projectile gives the best performance at most of the considered impact velocity conditions.Originality/valueThe proposed research outputs are original, innovative and, have lot of importance in defence applications particularly in arms and ammunitions.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45623285","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 : 2022-04-19DOI: 10.1108/ijsi-12-2021-0128
Fei Sun, Changjun Li
PurposeIn order to improve the comprehensive evaluation level of shield tunnel structure health, taking a subway tunnel section as an example, and combined with the onsite measured data, such as regular inspection, health monitoring and disease remediation, this paper introduces the variable weight theory to improve the traditional fixed-weight evaluation method from structural deformation, current durability and disease status.Design/methodology/approachConsidering the influence of the fluctuation of each index value on the index weight, a comprehensive structural health evaluation model of shield tunnel based on an improved variable weight matter-element extension model is proposed.FindingsCompared with the traditional fixed-weight evaluation method, this model can correct the evaluation distortion caused by the fluctuation of index value and has optimal effect.Originality/valueThe sensitive analysis shows that several key indicators of the main threats to tunnel structure are obtained to improve the efficiency of operation, maintenance and management of shield tunnel structure.
{"title":"A comprehensive evaluation method and application of shield tunnel structure health based on variable weight theory","authors":"Fei Sun, Changjun Li","doi":"10.1108/ijsi-12-2021-0128","DOIUrl":"https://doi.org/10.1108/ijsi-12-2021-0128","url":null,"abstract":"PurposeIn order to improve the comprehensive evaluation level of shield tunnel structure health, taking a subway tunnel section as an example, and combined with the onsite measured data, such as regular inspection, health monitoring and disease remediation, this paper introduces the variable weight theory to improve the traditional fixed-weight evaluation method from structural deformation, current durability and disease status.Design/methodology/approachConsidering the influence of the fluctuation of each index value on the index weight, a comprehensive structural health evaluation model of shield tunnel based on an improved variable weight matter-element extension model is proposed.FindingsCompared with the traditional fixed-weight evaluation method, this model can correct the evaluation distortion caused by the fluctuation of index value and has optimal effect.Originality/valueThe sensitive analysis shows that several key indicators of the main threats to tunnel structure are obtained to improve the efficiency of operation, maintenance and management of shield tunnel structure.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49317070","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 : 2022-04-12DOI: 10.1108/ijsi-03-2022-0025
Qingtian Deng, Shun‐Peng Zhu, Jin-Chao He, Xue-Kang Li, A. Carpinteri
PurposeEngineering components/structures with geometric discontinuities normally bear complex and variable loads, which lead to a multiaxial and random/variable amplitude stress/strain state. Hence, this study aims how to effectively evaluate the multiaxial random/variable amplitude fatigue life.Design/methodology/approachRecent studies on critical plane method under multiaxial random/variable amplitude loading are reviewed, and the computational framework is clearly presented in this paper.FindingsSome basic concepts and latest achievements in multiaxial random/variable amplitude fatigue analysis are introduced. This review summarizes the research status of four main aspects of multiaxial fatigue under random/variable amplitude loadings, namely multiaxial fatigue criterion, method for critical plane determination, cycle counting method and damage accumulation criterion. Particularly, the latest achievements of multiaxial random/variable amplitude fatigue using critical plane methods are classified and highlighted.Originality/valueThis review attempts to provide references for further research on multiaxial random/variable amplitude fatigue and to promote the development of multiaxial fatigue from experimental research to practical engineering application.
{"title":"Multiaxial fatigue under variable amplitude loadings: review and solutions","authors":"Qingtian Deng, Shun‐Peng Zhu, Jin-Chao He, Xue-Kang Li, A. Carpinteri","doi":"10.1108/ijsi-03-2022-0025","DOIUrl":"https://doi.org/10.1108/ijsi-03-2022-0025","url":null,"abstract":"PurposeEngineering components/structures with geometric discontinuities normally bear complex and variable loads, which lead to a multiaxial and random/variable amplitude stress/strain state. Hence, this study aims how to effectively evaluate the multiaxial random/variable amplitude fatigue life.Design/methodology/approachRecent studies on critical plane method under multiaxial random/variable amplitude loading are reviewed, and the computational framework is clearly presented in this paper.FindingsSome basic concepts and latest achievements in multiaxial random/variable amplitude fatigue analysis are introduced. This review summarizes the research status of four main aspects of multiaxial fatigue under random/variable amplitude loadings, namely multiaxial fatigue criterion, method for critical plane determination, cycle counting method and damage accumulation criterion. Particularly, the latest achievements of multiaxial random/variable amplitude fatigue using critical plane methods are classified and highlighted.Originality/valueThis review attempts to provide references for further research on multiaxial random/variable amplitude fatigue and to promote the development of multiaxial fatigue from experimental research to practical engineering application.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46202699","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 : 2022-03-30DOI: 10.1108/ijsi-01-2022-0009
Jinliang Liu, Fan Yan
PurposeIn this paper, the effects of geopolymer adhesive, the number of CFRP layers and the width of pre-crack on the flexural performance of reinforced concrete beams strengthened with CFRP were studied, and the flexural capacity of strengthened beams was calculated theoretically.Design/methodology/approachReinforced concrete beams were strengthened with CFRP by geopolymer adhesive, and flexural load tests were conducted to observe the reinforcement effect. Based on the method of calculating the flexural capacity of reinforced concrete beams, a theoretical calculation model on the flexural capacity of reinforced concrete beams strengthened with geopolymer adhesive bonded CFRP was established.FindingsThe test data shown the flexural capacity of epoxy resin adhesive CFRP strengthened reinforced concrete beams is 7.76% higher than that geopolymer adhesive is used. The flexural capacity of reinforced concrete beams strengthened with three layers of CFRP is 1.86% higher than that two layers are adopted. The mean ratio of the test data and the calculation results of the flexural capacity is 0.973, and the mean square error is 0.008. It can be seen that the test data are in good agreement with the theoretical value.Originality/valueThis paper provides data support for the popularization and application of the new environment-friendly reinforcement technology, contributes to the cause of environmental protection, and provides a new method for strengthening reinforced concrete beams.
{"title":"Study on flexural behavior of reinforced concrete beams strengthened with geopolymer adhesive bonded CFRP","authors":"Jinliang Liu, Fan Yan","doi":"10.1108/ijsi-01-2022-0009","DOIUrl":"https://doi.org/10.1108/ijsi-01-2022-0009","url":null,"abstract":"PurposeIn this paper, the effects of geopolymer adhesive, the number of CFRP layers and the width of pre-crack on the flexural performance of reinforced concrete beams strengthened with CFRP were studied, and the flexural capacity of strengthened beams was calculated theoretically.Design/methodology/approachReinforced concrete beams were strengthened with CFRP by geopolymer adhesive, and flexural load tests were conducted to observe the reinforcement effect. Based on the method of calculating the flexural capacity of reinforced concrete beams, a theoretical calculation model on the flexural capacity of reinforced concrete beams strengthened with geopolymer adhesive bonded CFRP was established.FindingsThe test data shown the flexural capacity of epoxy resin adhesive CFRP strengthened reinforced concrete beams is 7.76% higher than that geopolymer adhesive is used. The flexural capacity of reinforced concrete beams strengthened with three layers of CFRP is 1.86% higher than that two layers are adopted. The mean ratio of the test data and the calculation results of the flexural capacity is 0.973, and the mean square error is 0.008. It can be seen that the test data are in good agreement with the theoretical value.Originality/valueThis paper provides data support for the popularization and application of the new environment-friendly reinforcement technology, contributes to the cause of environmental protection, and provides a new method for strengthening reinforced concrete beams.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45789682","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 : 2022-03-28DOI: 10.1108/ijsi-10-2019-0103
K. Koulouris, C. Apostolopoulos
PurposeAs it is widely known, corrosion constitutes a major deterioration factor for reinforced concrete (RC) structures which are located on coastal areas. This phenomenon combined with repeated loads, as earthquake events, negatively affects their service life. Moreover, microstructure of steel reinforcing bars has significant impact either on their corrosion resistance or on their fatigue life.Design/methodology/approachIn the present manuscript an effort has been made to investigate the effect of corrosive factor on fatigue response for two types of steel reinforcement; Tempcore steel reinforcing bars and a new generation dual phase (DP) steel reinforcement.FindingsThe findings of this experimental study showed that DP steel reinforcement led to better results regarding its capacity to bear repeated loads to satisfactory degree after corrosion, although this type of steel has less stringent mechanical properties.Originality/valueAdditionally, a fatigue damage material indicator is proposed as a parameter that could rank material quality and its suitability for a certain application. The results of this investigation showed that the fatigue damage indicator can be used as an appropriate index in order to evaluate the overall performance of materials, in terms of strength and ductility capacity.
{"title":"Fatigue damage indicator of different types of reinforcing bars","authors":"K. Koulouris, C. Apostolopoulos","doi":"10.1108/ijsi-10-2019-0103","DOIUrl":"https://doi.org/10.1108/ijsi-10-2019-0103","url":null,"abstract":"PurposeAs it is widely known, corrosion constitutes a major deterioration factor for reinforced concrete (RC) structures which are located on coastal areas. This phenomenon combined with repeated loads, as earthquake events, negatively affects their service life. Moreover, microstructure of steel reinforcing bars has significant impact either on their corrosion resistance or on their fatigue life.Design/methodology/approachIn the present manuscript an effort has been made to investigate the effect of corrosive factor on fatigue response for two types of steel reinforcement; Tempcore steel reinforcing bars and a new generation dual phase (DP) steel reinforcement.FindingsThe findings of this experimental study showed that DP steel reinforcement led to better results regarding its capacity to bear repeated loads to satisfactory degree after corrosion, although this type of steel has less stringent mechanical properties.Originality/valueAdditionally, a fatigue damage material indicator is proposed as a parameter that could rank material quality and its suitability for a certain application. The results of this investigation showed that the fatigue damage indicator can be used as an appropriate index in order to evaluate the overall performance of materials, in terms of strength and ductility capacity.","PeriodicalId":45359,"journal":{"name":"International Journal of Structural Integrity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46252540","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：