非线性粘弹性梁的混沌运动

The integro-partial-differential equation that governs the dynamical behavior of homogeneous viscoelastic beams with geometric and material nonlinearities is established. The material of the beams obeys the Leaderman nonlinear constitutive relation. In the case of simple supported ends, the Galerkin method is applied to simplify the integro-partial-differential equation to a integro -differential equation. The equation is further simplified to a set of ordinary differential equations by introducing an additional variable. Finally, the numerical method is applied to investigate the dynamical behavior of the beam, and results show that chaos occurs in the motion of the beam.     

考虑剪切效应有限变形粘弹性板的动力稳定性

Based on Reddy‘s theory of plates with higher-order shear deformations and the Boltzmann superposition principles,the governing equations were established for dynamic stability of viscoelastic plates with finite deformations taking account of shear effects,The Galerkin method was applied to simplify the set of equations.The numerical methods in nonlinear dynamics were used to solve the simplified system.It could e seen that there are plenty of dynamic properties for this kind of viscoelastic plates under transverse harmonic loads.The influences of the transverse shear deformations and material parameter on the dynamic behavior of nonlinear viscoelatic plates were investigated.     

粘弹性开敞浅壳的动力学性质

On the basis of the Kármán-Donnell theory of thin shells with large deflections and the Boltzmann laws for linear viscoelastic materials, the mathematical model for viscoelastic open shallow shells was formulated. By using the Galerkin average method, the original integro-partial-differential dynamic system was simplified as a integro-ordinary-differential dynamic system, which can be transformed into a ordinary differential dynamic system by introducing new variables. The dynamical behavior was studied by some classical methods. Dynamical properties, such as, chaos, strange attractor, limit cycle etc., were discovered. Supported by the Development Foundation of Shanghai Municipal Commission of Education (99A01)     

规则、诚信、责任、法律:大学生海外实习应具备的四种意识——基于国外企业终止大学生海外实习案例的分析

海外实习在提升大学生综合能力的同时,也暴露出大学生跨文化能力的缺失,规则意识、诚信意识、责任意识、法律意识是大学生在海外实习中应具备的四种意识.     

海外实习育人平台的构建和思考

创新性人才培养是创新型国家建设的关键问题,而实践教学是学生综合素质和创新能力培养的重要环节.本文分析了创新性人才培养和实践教学的重要意义以及经济全球化对国际化人才培养的迫切性,介绍了在钱伟长"拆除四堵墙"办学理念指导下,上海大学在海外实习育人平台构建方面所进行的初步探索和主要措施,并对存在问题和努力方向进行了探讨.     

非线性粘弹性梁弯曲的失记效应

Based on the Leaderman constitutive relations in nonlinear viscoelasticity and the linear geometrical assumption, a mathematical model for the bending of nonlinear viscoelastic beams was established in this paper. The Laplace transformation method and the Titchmarsh theorem were used to prove that some relations exist between solutions to bending problems of visco- and elastic beams, which reveals the fugue effect of viscoelastic materials. The high-order Galerkin approximate solution to the quasi-static response of nonlinear viscoelastic beams under a step load was obtained by using the new method suggested in this paper as well as the Mathematica software and the Newton iteration technique.