Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be...Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation（FCP） theory rather than the currently used cumulative fatigue damage（CFD） theory. A unified fatigue life prediction（UFLP） method for marine structures has been proposed by the authors＇ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history（SLH） such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.展开更多
Magnesium(Mg)alloys,known for their low density and high specific strength,are widely used in the lightweight design of engineering structures.However,their complex mechanical behaviors,particularly including the cycl...Magnesium(Mg)alloys,known for their low density and high specific strength,are widely used in the lightweight design of engineering structures.However,their complex mechanical behaviors,particularly including the cyclic plasticity,damage,and fatigue failure influenced by dislocation slipping,twinning,detwinning,and their interactions,present significant challenges in ensuring the safety and reliability of Mg alloy components.Addressing these challenges requires a comprehensive understanding of such behaviors and their underlying micro-mechanisms,and the development of reliable constitutive models,damage models,and fatigue life prediction methods.This review highlights recent advancements in these topics by elaborating particularly on the intricate connections between the macroscopic plastic deformation and microscopic mechanisms of Mg alloys,and the initiation and propagation of microcracks and microvoids observed through experimental studies and numerical simulations.We also discuss the progress in the theoretical models that predict the cyclic plasticity and/or fatigue life of Mg alloys.Finally,some topics for future research are suggested.展开更多
基金financially supported by the Fourth Term of"333 Engineering"Program of Jiangsu Province(Grant No.BRA2011116)Youth Foundation of Jiangsu Province(Grant No.BK2012095)Special Program for Hadal Science and Technology of Shanghai Ocean University(Grant No.HAST-T-2013-01)
文摘Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation（FCP） theory rather than the currently used cumulative fatigue damage（CFD） theory. A unified fatigue life prediction（UFLP） method for marine structures has been proposed by the authors＇ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history（SLH） such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.
基金supported by the National Natural Science Foundation of China(Nos.12192210,12192214,11921002,and 12302076)China Postdoctoral Science Foundation(No.2024M761630).
文摘Magnesium(Mg)alloys,known for their low density and high specific strength,are widely used in the lightweight design of engineering structures.However,their complex mechanical behaviors,particularly including the cyclic plasticity,damage,and fatigue failure influenced by dislocation slipping,twinning,detwinning,and their interactions,present significant challenges in ensuring the safety and reliability of Mg alloy components.Addressing these challenges requires a comprehensive understanding of such behaviors and their underlying micro-mechanisms,and the development of reliable constitutive models,damage models,and fatigue life prediction methods.This review highlights recent advancements in these topics by elaborating particularly on the intricate connections between the macroscopic plastic deformation and microscopic mechanisms of Mg alloys,and the initiation and propagation of microcracks and microvoids observed through experimental studies and numerical simulations.We also discuss the progress in the theoretical models that predict the cyclic plasticity and/or fatigue life of Mg alloys.Finally,some topics for future research are suggested.
