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| 1 | Nonlinear combination parametric resonance of axially accelerating viscoelastic strings constituted by the standard linear solid model显示文摘Nonlinear combination parametric resonance is investigated for an axially accelerating viscoelastic string.The governing equation of in-planar motion of the string is established by introducing a coordinate transform in the Eulerian equation of a string with moving boundaries.The string under investigation is constituted by the standard linear solid model in which the material,not partial,time derivative was used.The governing equation leads to the Mote model for transverse vibration by omitting the longitudinal component and higher order terms.The Kirchhoff model is derived from the Mote model by replacing the tension with the averaged tension over the string.The two models are respectively analyzed via the method of multiple scales for principal parametric resonance.The amplitudes and the existence conditions of steady-state response and its stability can be numerically determined.Numerical calculations demonstrate the effects of the string material parameters,the initial tension,and the axial speed fluctuation amplitude.The outcomes of the two models are qualitatively and quantitatively compared. | LIM C.W. | 2010 | Science China(Technological Sciences)2010，53，3： | 5 |
| 2 | Static analysis of ultra-thin beams based on a semi-continuum model显示文摘A linear semi-continuum model with discrete atomic layers in the thickness direction was developed to investigate the bending behaviors of ultra-thin beams with nanoscale thickness.The theoretical results show that the deflection of an ultra-thin beam may be enhanced or reduced due to different relaxation coefficients.If the relaxation coefficient is greater/less than one,the deflection of micro/nano-scale structures is enhanced/reduced in comparison with macro-scale structures.So,two opposite types of size-dependent behaviors are observed and they are mainly caused by the relaxation coefficients.Comparisons with the classical continuum model,exact nonlocal stress model and finite element model (FEM) verify the validity of the present semi-continuum model.In particular,an explanation is proposed in the debate whether the bending stiffness of a micro/nano-scale beam should be greater or weaker as compared with the macro-scale structures.The characteristics of bending stiffness are proved to be associated with the relaxation coefficients. | Cheng Li Zhi-Jun Zheng Ji-Lin Yu C.W. Lim | 2011 | Acta Mechanica Sinica2011，27，5： | 5 |
| 3 | TWISTING STATICS AND DYNAMICS FOR CIRCULAR ELASTIC NANOSOLIDS BY NONLOCAL ELASTICITY THEORY显示文摘The torsional static and dynamic behaviors of circular nanosolids such as nanoshafts, nanorods and nanotubes are established based on a new nonlocal elastic stress field theory. Based on a new expression for strain energy with a nonlocal nanoscale parameter, new higher-order governing equations and the corresponding boundary conditions are first derived here via the variational principle because the classical equilibrium conditions and/or equations of motion can- not be directly applied to nonlocal nanostructures even if the stress and moment quantities are replaced by the corresponding nonlocal quantities. The static twist and torsional vibration of circular, nonlocal nanosolids are solved and discussed in detail. A comparison of the conventional and new nonlocal models is also presented for a fully fixed nanosolid, where a lower-order governing equation and reduced stiffness are found in the conventional model while the new model reports opposite solutions. Analytical solutions and numerical examples based on the new nonlocal stress theory demonstrate that nonlocal stress enhances stiffness of nanosolids, i.e. the angular displacement decreases with the increasing nonlocal nanoscale while the natural frequency increases with the increasing nonlocal nanoscale. | Cheng Li C.W. Lim JiUn Yu | 2011 | Acta Mechanica Solida Sinica2011，24，6： | 3 |
| 4 | A variational energy approach for electromechanical analysis of thick piezoelectric beam显示文摘A new two dimensional coupled electromechanical model for a thick, laminated beam with piezoelectric and isotropic lamina subjected to static external electric loading is developed. The model combined the first order shear deformation theory for the relatively thick elastic core and linear piezoelectric theory for the piezoelectric lamina. The actuation response is induced through the application of external electric voltage. Rayleigh-Ritz method is adopted to model the displacement and potential fields of the beam and governing equations were finally derived from the variational energy principle. The model allows the piezoelectric lamina to be formulated via a two-dimensional model because of the strong electro-mechanical coupling and the presence of a two-dimensional electric field. Numerical examples of piezoelectric laminated beam are presented. It is shown in this paper that a one-dimensional model for the piezoelectric beam-like layer is inadequate. | LAU C.W.H. LIM C.W. LEUNG A.Y.T | 2005 | Journal of Zhejiang University-Science A(Applied Physics & Engineering)2005，6，9： | 1 |
| 5 | Stress analysis of anisotropic thick laminates in cylindrical bending using a semi-analytical approach显示文摘Semi-analytical elasticity solutions for bending of angle-ply laminates in cylindrical bending are presented using the state-space-based differential quadrature method (SSDQM). Partial differential state equation is derived from the basic equations of elasticity based on the state space concept. Then, the differential quadrature (DQ) technique is introduced to discretize the longitu- dinal domain of the plate so that a series of ordinary differential state equations are obtained at the discrete points. Meanwhile, the edge constrained conditions are handled directly using the stress and displacement components without the Saint-Venant principle. The thickness domain is solved analytically based on the state space formalism along with the continuity conditions at interfaces. The present method is validated by comparing the results to the exact solutions of Pagano’s problem. Numerical results for fully clamped thick laminates are presented, and the influences of ply angle on stress distributions are discussed. | LU Chao-feng LIM C.W. XU Feng | 2007 | Journal of Zhejiang University-Science A(Applied Physics & Engineering)2007，8，11： | 1 |
| 6 | Dynamic buckling of cylindrical shells subject to an axial impact in a symplectic system显示文摘 | Xinsheng Xu Yuan Ma C.W. Lim Hongjie Chu | 2005 | International Journal of Solids and Structures2005，，13： | 1 |
| 7 | Sibutramine improves fat distribution and insulin resistance, and increases serum adiponectin levels in Korean obese nondiabetic premenopausal women显示文摘 | D.M. Kim S.J. Yoon C.W. Ahn B.S. Cha S.K. Lim K.R. Kim H.C. Lee K.B. Huh | 2004 | Diabetes Research and Clinical Practice2004，，： | 1 |
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