Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact ...Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact force of a metal beam based on maximal normal yield surface are derived by membrane factor method(MFM),then the results are compared with repeated impact tests.It can be found that the solutions based on MFM are between the upper and lower bounds,and very close to the results of the repeated impact tests,indicating the theoretical model proposed can predict the plastic responses of the metal beam accurately.What’s more,the influences of impact location and boundary condition on the dynamic responses of the beam subjected to repeated impacts are determined.Results show that,as the distance of impact location from the middle span of the beam increases,the permanent deflection decreases,while the impact force increases.Meanwhile,the influences of impact location enhance as the impact number increases.When the permanent deflection is smaller than the thickness,the effect of boundary condition on the plastic responses is significant.However,when the deflection is larger than the thickness,the beam will be like a string and only axial force works,resulting in little influence of boundary condition on the plastic responses of the beam.展开更多
文章运用文献计量方法,以美国科学情报研究所开发的Web of Science数据库为数据源基础,检索了有关研究影响因子的文献,并从文献量、著者、机构、核心期刊、引文等角度进行了统计和分析,以定量数据从侧面反映了影响因子这一评价期刊质量...文章运用文献计量方法,以美国科学情报研究所开发的Web of Science数据库为数据源基础,检索了有关研究影响因子的文献,并从文献量、著者、机构、核心期刊、引文等角度进行了统计和分析,以定量数据从侧面反映了影响因子这一评价期刊质量的指标在其被提出之后30余年内的发展情况。展开更多
本文以Web of Knowledge为检索平台,从总被引频次、发表文章数量、单篇文章被引用次数、引用作者分布等方面,基于地理学学科特点和文献计量学方法,统计分析了《中国地理科学》(英文版)近年来影响因子的变化情况和影响因子下降的原因,总...本文以Web of Knowledge为检索平台,从总被引频次、发表文章数量、单篇文章被引用次数、引用作者分布等方面,基于地理学学科特点和文献计量学方法,统计分析了《中国地理科学》(英文版)近年来影响因子的变化情况和影响因子下降的原因,总结了该刊为提高影响因子和总被引频次所采取的改进措施,为该刊未来的发展提供指导,也为其他同类刊物提供借鉴。展开更多
文摘Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact force of a metal beam based on maximal normal yield surface are derived by membrane factor method(MFM),then the results are compared with repeated impact tests.It can be found that the solutions based on MFM are between the upper and lower bounds,and very close to the results of the repeated impact tests,indicating the theoretical model proposed can predict the plastic responses of the metal beam accurately.What’s more,the influences of impact location and boundary condition on the dynamic responses of the beam subjected to repeated impacts are determined.Results show that,as the distance of impact location from the middle span of the beam increases,the permanent deflection decreases,while the impact force increases.Meanwhile,the influences of impact location enhance as the impact number increases.When the permanent deflection is smaller than the thickness,the effect of boundary condition on the plastic responses is significant.However,when the deflection is larger than the thickness,the beam will be like a string and only axial force works,resulting in little influence of boundary condition on the plastic responses of the beam.
文摘本文以Web of Knowledge为检索平台,从总被引频次、发表文章数量、单篇文章被引用次数、引用作者分布等方面,基于地理学学科特点和文献计量学方法,统计分析了《中国地理科学》(英文版)近年来影响因子的变化情况和影响因子下降的原因,总结了该刊为提高影响因子和总被引频次所采取的改进措施,为该刊未来的发展提供指导,也为其他同类刊物提供借鉴。
