Linear viscoelastic model for bending and torsional modes in fluid membranes

This paper develops and applies a linear viscoelastic model for bending and torsional modes of fluid membranes, based on the nonlinear Cosserat surface fluid model. The linearized fluid membrane model in spherical and cylindrical geometries is shown to decouple bending and torsional viscoelastic modes. It is found that solutions of the membrane viscoelastic model to small-amplitude oscillatory bending and torsion allows for the measurement of the bending and the torsion viscosity. The model and its potential in characterizing the bending and torsion viscoelasticity of membranes complements the on-going efforts to establish the role of curvature in dissipative process of biological membranes.     

The torsion potential function of hydrogen peroxide and disulfan molecules

A method for constructing the torsion potential function of hydrogen peroxide and disulfan molecules which takes into account the magnitudes of intramolecular interactions is suggested. The new representation of the potential is used to calculate the torsion spectra of the molecules indicated. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 450–452, July–August, 2000.     

Saint-Venant torsion analysis of bars with rectangular cross-section and effective coating layers

This paper investigates the torsion analysis of coated bars with a rectangular cross-section. Two opposite faces of a bar are coated by two isotropic layers with different materials of the original substrate that are perfectly bonded to the bar. With the Saint-Venant torsion theory, the governing equation of the problem in terms of the warping function is established and solved using the finite Fourier cosine transform. The state of stress on the cross-section, warping of the cross-section, and torsional rigidity of the bar are evaluated. Effects of thickness of the coating layers and material properties on these quantities are investigated. A set of graphs are provided that can be used to determine the coating thicknesses and material properties so as to keep the maximum von Mises stress on the cross-section below an allowable value for effective use of the coating layer.     

复合材料力矩管扭转性能的研究

为了研究缠绕角度对玻璃纤维增强复合材料管(GFRP)扭转性能的影响和给在实际应用中提供依据,本文研究采用湿法缠绕成型工艺制得了具有不同缠绕角度的GFRP管.通过测试缠绕管的破坏扭矩来分析影响复合材料缠绕管扭转性能的各项因素,并与理论计算值进行了比较.研究结果表明,缠绕管扭转破坏的主要形式为面内剪切破坏.当缠绕角度在25°至60°范围内变化时,随着缠绕角度的增大,复合材料缠绕管的壁厚逐渐减小,抗剪性能逐渐减弱且扭转破坏形式有分层情况出现.当缠绕角是25°时,缠绕管的抗扭性能最佳,最大扭矩为118N.m,对应的扭转强度为209MPa.     

Shear deformation effect in plates stiffened by parallel beams

In this paper a general solution for the analysis of shear deformable stiffened plates subjected to arbitrary loading is presented. According to the proposed model, the arbitrarily placed parallel stiffening beams of arbitrary doubly symmetric cross section are isolated from the plate by sections in the lower outer surface of the plate, taking into account the arising tractions in all directions at the fictitious interfaces. These tractions are integrated with respect to each half of the interface width resulting two interface lines, along which the loading of the beams as well as the additional loading of the plate is defined. Their unknown distribution is established by applying continuity conditions in all directions at the interfaces. The utilization of two interface lines for each beam enables the nonuniform distribution of the interface transverse shear forces and the nonuniform torsional response of the beams to be taken into account. The analysis of both the plate and the beams is accomplished on their deformed shape taking into account second-order effects. The analysis of the plate is based on Reissner’s theory, which may be considered as the standard thick plate theory with which all others are compared, while the analysis of the beams is performed employing the linearized second order theory taking into account shear deformation effect. Six boundary value problems are formulated and solved using the analog equation method (AEM), a BEM based method. The solution of the aforementioned plate and beam problems, which are nonlinearly coupled, is achieved using iterative numerical methods. The adopted model permits the evaluation of the shear forces at the interfaces in both directions, the knowledge of which is very important in the design of prefabricated ribbed plates. The effectiveness, the range of applications of the proposed method and the influence of shear deformation effect are illustrated by working out numerical examples with great practical interest.     

Classification of Teleparallel Homothetic Vector Fields in Cylindrically Symmetric Static Space-Times in Teleparallel Theory ofGravitation

In this paper we classify cylindrically symmetric static space-timesaccording to their teleparallel homothetic vector fields using directintegration technique. It turns out that the dimensions of the teleparallelhomothetic vector fields are 4, 5, 7 or 11, which are the same in numbers asin general relativity. In case of 4, 5 or 7 proper teleparallel homotheticvector fields exist for the special choice to the space-times. In the caseof 11 teleparallel homothetic vector fields the space-time becomes Minkowskiwith all the zero torsion components. Teleparallel homothetic vector fieldsin this case are exactly the same as in general relativity. It is importantto note that this classification also covers the plane symmetric static space-times.     

Finding Dirac Spin Effect in NUT Spacetime

In the present study, we are interested in finding the spin precession of a Dirac particle in expanding and rotating NUT spaeetime. A tetrad with two functions to be determined is applied to the field equation of the teleparallel theory of gravity via a coordinate transformation. The vector, the axial-vector and the tensor parts of the torsion tensor are obtained. We found that the vector parts are in the radial and Ф-directions. The axial-vector torsion is along r-direction while its other components along θ and oh-directions vanish everywhere. The vector connected with Dirac spin has been evaluated as well.     

Torsion Axial-Vector in an Alternative Kerr Tetrad Field

In the framework of parallelism general relativity, the torsion axial-vector in the rotating gravitational field is studied in terms of the alternative Kerr tetrad. In the case of the weak field and slow rotation approximation, we obtain that the torsion axial-vector possesses the dipole-like structure. Furthermore, the effect of massive neutrino spin precession in this field is mentioned.     

The coupling method for torsion problem of the square cross-section bar with cracks

By coupling natural boundary element method (NBEM) with FEM based on domain decomposition, the torsion problem of the square cross-sections bar with cracks have been studied, the stresses of the nodes of the cross-sections and the stress intensity factors have been calculated, and some distribution pictures of the stresses have been drawn. During computing, the effect of the relaxed factors to the convergence speed of the iterative method has been discussed. The results of the computation have confirmed the advantages of the NBEM and its coupling with the FEM. Foundation item: the State Key Laboratory of Science and Engineering Computation Biography: ZHAO Hui-ming (1971-)     

Inelastic coupled response of eccentric buildings with respect to different earthquake intensity

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｂｅｈａｖｉｏｒｏｆｌａｔｅｒａｌ＿ｔｏｒｓｉｏｎａｌｃｏｕｐｌｅｄｂｕｉｌｄｉｎｇｉｎｔｈｅｉｎｅｌａｓｔｉｃｒａｎｇｅｈａｄｂｅｅｎｗｉｄｅｌｙｉｎｖｅｓｔｉｇａｔｅｄ.ＫａｎａｎｄＣｈｏｐｒａ(1981)[1]ｓｔｕｄｉｅｄａｏｎｅ＿ｓｔｏｒｙｍｏｄｅｌｗｉｔｈｓｉｎｇｌｅｌａｔｅｒａｌｒｅｓｉｓｔａｎｔｅｌｅｍｅｎｔａｎｄｒｅａｃｈｅｄｔｈｅｃｏｎｃｌｕｓｉｏｎｔｈａｔｇｅｎｅｒａｌｌｙｔｈｅｒｅｓｐｏｎｓｅｉｎｔｈｅｉｎｅｌａｓｔｉｃｒａｎｇｅｉｓａｆｆｅｃｔｅｄｂ…