Based on the Sanders thin shell theory and Reddy's higher order shell theory,a general refined shell theory is developed for the analysis of stresses and deformations ofpneumatic radial tires of composite construc...Based on the Sanders thin shell theory and Reddy's higher order shell theory,a general refined shell theory is developed for the analysis of stresses and deformations ofpneumatic radial tires of composite construction. For easy and efficient simulation of the tire apiecewise Rayleigh-Ritz technique is proposed and applied to get a numerical solution to thenonlinear structural problem. Bezier polynomials are used to approximate both the geometry of thesurface of reference and displacement fields of the tires. Stress distributions and deformations ofthe tires subjected to uniform inflation pressure are computed and discussed in details. Fromcomparison of the present results with the numerical predictions by 3D finite element method, it hasbeen shown that the present solution procedure is accurate and applicable to much complicatedtime-consuming nonlinear analysis for the high quality tire.展开更多
Free vibration analysis of non-homogeneous orthotropic plates resting on a Pasternak type of elastic foundation is investigated. A set of admissible orthogonal polynomials are generated with Gram-Schmidt orthogonaliza...Free vibration analysis of non-homogeneous orthotropic plates resting on a Pasternak type of elastic foundation is investigated. A set of admissible orthogonal polynomials are generated with Gram-Schmidt orthogonalization procedure and adopted in the Rayleigh-Ritz method. Accuracy and applicability of the method are examined by comparison of the results for different boundary conditions and material types with those available in literature. It is found that this method has good accuracy regardless of type of boundary condition and yields very accurate results even with low number of terms of orthogonal polynomials for the first mode of vibration. For higher modes of vibration, higher terms of orthogonal polynomials should be used. The effects of foundation parameter, density and non-homogeneity parameters on natural frequency are examined. It is concluded that natural frequency of plates are more sensitive to shearing layer coefficient rather than Winkler coefficient and density parameter has weakening effect on natural frequency.展开更多
A rotor manipulation mechanism for micro unmanned helicopter utilizing the inertia and the elasticity of the rotor is introduced. The lagging motion equation of the rotor blades is established, and then the natural fr...A rotor manipulation mechanism for micro unmanned helicopter utilizing the inertia and the elasticity of the rotor is introduced. The lagging motion equation of the rotor blades is established, and then the natural frequencies and mode shapes of the blade for the helicopter are studied by using beam characteristic orthogonal polynomials by the Rayleigh-Ritz method. The variation of natural frequencies with the speed of rotation and the mode shapes at different rotational speeds are plotted. The using of orthogonal polynomials for the bending shapes enables the computation of higher natural frequencies of any order to be accomplished without facing any difficulties.展开更多
Based on Reddy higher-order shear deformation theory, a general refined shell theory suitable to nonlinear analysis of tire structure is developed in this paper. The piece-wise Rayleigh-Ritz procedure and Bezier polyn...Based on Reddy higher-order shear deformation theory, a general refined shell theory suitable to nonlinear analysis of tire structure is developed in this paper. The piece-wise Rayleigh-Ritz procedure and Bezier polynomials are applied to analyze deformations and stress distributions of the multlayered tire subjected to uniform inflation in detail. Furthermore, 3-dimension FEM analysis of laminated tire by standard software ANSYS is adopted to compare with the present model. It is demonstrated that both two solutions are in fairly good agreement.展开更多
Hard-magnetic soft materials exhibit significant shape morphing capabilities under non-contact magnetic actuation, yet their particulate composition tends to compromise material toughness. To quantify particle-matrix ...Hard-magnetic soft materials exhibit significant shape morphing capabilities under non-contact magnetic actuation, yet their particulate composition tends to compromise material toughness. To quantify particle-matrix interactions, we present a mechanics model describing the energy functional of planar magnetic composites. Through the Fourier series, the analytical solutions for stress distribution and interfacial peeling length of a single particle-polymer unit are derived with the Rayleigh-Ritz method under uniaxial tension. The calculated results of stress fields without the magnetic field agree well with those of the finite element method. The effects of external magnetic field strength and particle content on the stress distribution and peeling length are fully explored, and the enhanced analytical outcomes are obtained through numerical prediction.These insights can be used to validate the reliability of engineering designs, including adaptive structures, micro-electro-mechanical sensors, and soft robotic systems.展开更多
文摘Based on the Sanders thin shell theory and Reddy's higher order shell theory,a general refined shell theory is developed for the analysis of stresses and deformations ofpneumatic radial tires of composite construction. For easy and efficient simulation of the tire apiecewise Rayleigh-Ritz technique is proposed and applied to get a numerical solution to thenonlinear structural problem. Bezier polynomials are used to approximate both the geometry of thesurface of reference and displacement fields of the tires. Stress distributions and deformations ofthe tires subjected to uniform inflation pressure are computed and discussed in details. Fromcomparison of the present results with the numerical predictions by 3D finite element method, it hasbeen shown that the present solution procedure is accurate and applicable to much complicatedtime-consuming nonlinear analysis for the high quality tire.
文摘Free vibration analysis of non-homogeneous orthotropic plates resting on a Pasternak type of elastic foundation is investigated. A set of admissible orthogonal polynomials are generated with Gram-Schmidt orthogonalization procedure and adopted in the Rayleigh-Ritz method. Accuracy and applicability of the method are examined by comparison of the results for different boundary conditions and material types with those available in literature. It is found that this method has good accuracy regardless of type of boundary condition and yields very accurate results even with low number of terms of orthogonal polynomials for the first mode of vibration. For higher modes of vibration, higher terms of orthogonal polynomials should be used. The effects of foundation parameter, density and non-homogeneity parameters on natural frequency are examined. It is concluded that natural frequency of plates are more sensitive to shearing layer coefficient rather than Winkler coefficient and density parameter has weakening effect on natural frequency.
基金This work was supported by the "985"foundation of China(No.082200102).
文摘A rotor manipulation mechanism for micro unmanned helicopter utilizing the inertia and the elasticity of the rotor is introduced. The lagging motion equation of the rotor blades is established, and then the natural frequencies and mode shapes of the blade for the helicopter are studied by using beam characteristic orthogonal polynomials by the Rayleigh-Ritz method. The variation of natural frequencies with the speed of rotation and the mode shapes at different rotational speeds are plotted. The using of orthogonal polynomials for the bending shapes enables the computation of higher natural frequencies of any order to be accomplished without facing any difficulties.
文摘Based on Reddy higher-order shear deformation theory, a general refined shell theory suitable to nonlinear analysis of tire structure is developed in this paper. The piece-wise Rayleigh-Ritz procedure and Bezier polynomials are applied to analyze deformations and stress distributions of the multlayered tire subjected to uniform inflation in detail. Furthermore, 3-dimension FEM analysis of laminated tire by standard software ANSYS is adopted to compare with the present model. It is demonstrated that both two solutions are in fairly good agreement.
基金supported by the National Natural Science Foundation of China (Nos. 11972375 and12211530028)the Special Funds for the Basic Scientific Research Expenses of Central Government Universities of China (No. 2472022X03006A)
文摘Hard-magnetic soft materials exhibit significant shape morphing capabilities under non-contact magnetic actuation, yet their particulate composition tends to compromise material toughness. To quantify particle-matrix interactions, we present a mechanics model describing the energy functional of planar magnetic composites. Through the Fourier series, the analytical solutions for stress distribution and interfacial peeling length of a single particle-polymer unit are derived with the Rayleigh-Ritz method under uniaxial tension. The calculated results of stress fields without the magnetic field agree well with those of the finite element method. The effects of external magnetic field strength and particle content on the stress distribution and peeling length are fully explored, and the enhanced analytical outcomes are obtained through numerical prediction.These insights can be used to validate the reliability of engineering designs, including adaptive structures, micro-electro-mechanical sensors, and soft robotic systems.
