＜正＞To study the dispersion behavior of wave in multiferroic hollow cylinder,a formulation for the method of re...
Jun ZHU~1 Wei-Qiu CHEN~(2,*) 1 Department of Mechanical Engineering,Zhejiang University,Yuquan Campus,Hangzhou 310027 2 Department of Engineering Mechanics,Zhejiang University,Yuquan Campus,Hangzhou
The free vibration and transient wave in a prestressed Rayleigh-Timoshenko beam subject to arbitrary transverse forces are analyzed by the newly developed method of reverberation-ray matrix (MRRM). The effects of shear deformation and rotational inertia are taken into consideration. With a Fourier transform technique, the general wave solutions with two sets of unknown amplitude coefficients are obtained in the transformed domain for an unbonded prestressed beam under the action of arbitrary external excitations. From the coupling at joints and the compatibility of displacements in each member, the free and forced vibration responses of a beam with various boundary conditions are finally evaluated through certain numerical algorithms. Results are presented for a simply-supported beam subject to either a point fixed load or moving load. Good agreement with the finite element method (FEM) is obtained. The present work is instructive for high-speed railway bridge design and structural health monitoring.
The method of reverberation-ray matrix （MRRM） is extended and modified for the analysis of free wave propagation in anisotropic layered elastic media. A general, numerically stable formulation is established within the state space framework. The compatibility of physical variables in local dual coordinates gives the phase relation, from which exponentially growing functions are excluded. The interface and boundary conditions lead to the scattering relation, which avoids matrix inversion operation. Numerical examples are given to show the high accuracy of the present MRRM.
A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.
GUO YongQiang1, CHEN WeiQiu2,3 & ZHANG YongLiang4 1 Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, and School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China
<正>The static and dynamic problems of an imperfectly bonded,orthotropic,piezoelectric laminate in cylindrical ...
Yun-ying ZHOU,Wei-qiu CHEN School of Aeronautics and Astronautics,Zhejiang University,Hangzhou 310027,China Chao-feng L Department of Civil Engineering,Zijingang Campus,Zhejiang University,Hangzhou 310058,China
<正>The method of reverberation-ray matrix(MRRM) are modified and extended to the analysis of wave propagation ...
Yong-qiang GUO Key Laboratory of Mechanics on Disaster and Environment in Western China,Ministry of Education, and School of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China Wei-qiu CHEN Key Laboratory of Soft Soils and Geoenvironmental Engineering,Ministry of Education, and Department of Civil Engineering,Zhejiang University,Hangzhou 310027,China
The mechanical behavior of sand is very complex, and depends on factors including confining pressure, density, and drainage condition. A soil mass can be contractive or dilative when subjected to shear loading, and eventually reaches an ultimate state, referred to as the critical state in soil mechanics. Conventional approach to explore the mechanical behavior of sand mainly relies on the experimental tests in laboratory. This paper gives an alternative view to this subject using discrete element method (DEM), which has attracted much attention in recent years. The implementation of the DEM is carried out by a series of numerical tests on granular assemblies with varying initial densities and confining pressures, under different test configurations. The results demonstrate that such numerical simulations can produce correct responses of the sand behavior in general, including the critical state response, as compared to experimental observations. In addition, the DEM can further provide details of the microstructure evolutions during shearing processes, and the resulting induced anisotropy can be fully captured and quantified in the particle scale.
The elastic modulus of asphalt concrete(AC) is an important material parameter for pavement design.The prediction and determination of elastic modulus,however,largely depends on laboratory tests which cannot reflect explicitly the influence of the microstructure of AC.To this end,a micromechanical model based on stepping scheme is adopted.Consideration is given to the influence of interfacial debonding and interlocking effect between the aggregates and asphalt mastic using the concept of effective bonding.Tests on asphalt mixture with various microstructures are conducted to verify the proposed approach.It is shown that the prediction is generally in agreement with experimental results.Parameters affecting the elastic modulus of AC are also discussed in light of the proposed method.
