For the first time, the isogeometric analysis(IGA) approach is used to model and analyze free and forced vibrations of doubly-curved magneto-electro-elastic(MEE) composite shallow shell resting on the visco-Pasternak ...For the first time, the isogeometric analysis(IGA) approach is used to model and analyze free and forced vibrations of doubly-curved magneto-electro-elastic(MEE) composite shallow shell resting on the visco-Pasternak foundation in a hygro-temperature environment. The doubly-curved MEE shallow shell types include spherical shallow shell, cylindrical shallow shell, saddle shallow shell, and elliptical shallow shell subjected to blast load are investigated. The Maxwell equation and electromagnetic boundary conditions are used to determine the vary of the electric and magnetic potentials. The MEE shallow shell's equations of motion are derived from Hamilton's principle and refined higher-order shear theory. Then, the IGA method is used to derive the laws of natural frequencies and dynamic responses of the shell under various boundary conditions. The accuracy of the model and method is verified through reliable numerical comparisons. Aside from this, the impact of the input parameters on the free and forced vibration of the doubly-curved MEE shallow shell is examined in detail. These results may be useful in the design and manufacture of military structures such as warships, fighter aircraft, drones and missiles.展开更多
提高竞技体育人才培养效率是保障竞技体育健康稳定发展的重要途径。研究系统梳理了近年来优秀运动员发展环境(athletic talent development environment,ATDE)领域的理论进展和实证研究,从打造良好育人环境的角度,介绍了诸多环境因素在...提高竞技体育人才培养效率是保障竞技体育健康稳定发展的重要途径。研究系统梳理了近年来优秀运动员发展环境(athletic talent development environment,ATDE)领域的理论进展和实证研究,从打造良好育人环境的角度,介绍了诸多环境因素在运动员成功发展过程中的功能角色和重要性;基于整体生态学途径(holistic ecological approach,HEA)的理论与实证研究进展,分析了ATDE的结构和过程模型,以及环境因素的有效特征和无效特征;人才发展环境要素的良性功能和不良功能特征初步概念框架进一步揭示了环境因素对运动员发展的双向作用。研究认为,成功的ATDE具备支持性训练团队、明确的组织文化和整合各方努力的能力等,而无效的环境则缺乏这些特征。已有实证研究通过对具体运动员发展环境和特定环境要素进行分析,结合HEA等理论框架,从运动员、教练员等多个视角出发,探讨ATDE对运动成绩与运动员个人发展的影响。未来需关注跨文化研究、长期追踪研究、环境因素的综合评估,并强化实证研究的深度和广度。展开更多
文摘For the first time, the isogeometric analysis(IGA) approach is used to model and analyze free and forced vibrations of doubly-curved magneto-electro-elastic(MEE) composite shallow shell resting on the visco-Pasternak foundation in a hygro-temperature environment. The doubly-curved MEE shallow shell types include spherical shallow shell, cylindrical shallow shell, saddle shallow shell, and elliptical shallow shell subjected to blast load are investigated. The Maxwell equation and electromagnetic boundary conditions are used to determine the vary of the electric and magnetic potentials. The MEE shallow shell's equations of motion are derived from Hamilton's principle and refined higher-order shear theory. Then, the IGA method is used to derive the laws of natural frequencies and dynamic responses of the shell under various boundary conditions. The accuracy of the model and method is verified through reliable numerical comparisons. Aside from this, the impact of the input parameters on the free and forced vibration of the doubly-curved MEE shallow shell is examined in detail. These results may be useful in the design and manufacture of military structures such as warships, fighter aircraft, drones and missiles.
