Papers by Keyword: Orthotropic

Abstract: Analytical solutions are derived for multifunctional N-layered rectangular plates. The multilayered plate may consist of linear elastic or piezoelectric laminates of arbitrary thickness. The related equations and formulae are developed based on the Stroh like formalism. Solutions for multilayered plates are expressed in terms of the propagator matrix and satisfy the continuity conditions of material layers. Various types of electrical and mechanical loading may be considered. Numerical results of stresses, electric potential and displacement for some multifunctional multilayered plates are analyzed

Abstract: The problem of anti-plane crack in infinity orthotropic functionally graded materials is studied by using of integral transforms-dual integral equations. The shear modulus in the two principal directions of the functionally graded material was assumed to vary proportionately as gradient model of double parameters. And the variation curves of the dimensionless stress intensity factor with the orthogonal parameter and the crack length have been obtained by using the mathematical software .The results shows that stress intensity factor increases with the increasing of and a. It means that stress intensity factor decreases as the shear modulus of perpendicular to crack direction increased.

Abstract: In orthotropic bridge decks, the rib to floorbeam connection is a major source of fatigue problems. Commonly, the trapezoidal ribs cross the floorbeam continuously necessitating clearance holes in its web, and frequently additional web cutouts are foreseen to relieve the ribs lower edges. This solution is favorable for rib cracking but will generate stress concentrations in the web itself. The shape of the additional cutout has a major influence on the sizes of the concentrations rendering differences of a factor 2 or 3 for corresponding overall geometries and loading schemes. Various authors have studied cutout shapes through full scale testing or by computation by finite element modeling. This paper presents such a study, but focuses on the influence of the finite element modeling itself. It is shown that the mesh density, the element type, the choice between shell and volume elements. This is an important finding and should not be overlooked when comparing finite element based results to coded values or measured results. In order to do so, the results of the numerical work are compared to strain results from full scale tests.

Abstract: Clad plates welding of stainless steel welding on interlayer between grass roots and the transition layer is a key technology.Structure and properties of welded joints is very uneven,and there have often welding repair cracks. Clad plates of stainless steel material is used to weld under construction in the Southern link’s railway bridge for the first time at home .However, there occurs welding warpage of the convex parts and roughness appears excessive on the overall clad plates and severe deformation, and the quality of railway bridge is affected seriously. Reasons of the impacting welding quality are analyzed and specific measures to control them are proposed and the construction program is optimized.the efficiency and quality of welding can be improved ,a good foundation for the compound plates welding is layed,it will be contribute to ensure the overall quality of the welding quality of railway bridge especially the use of clad plates.

Abstract: 1-3 orthotropic cement based piezoelectric composites were fabricated by cut-filling and arrange-filling technique, using PZT-51 ceramic as functional material and cement as passive matrix. 1-3 orthotropic cement based piezoelectric composites were prepared into Acoustic Emission (AE) sensors, the attenuation of AE signal on the concrete and the response of different sensors on the concrete with increasing distance were researched. The results showed that the signal strength received by sensing element increases with the increasing PZT volume fraction; signal peaks and amplitude decrease gradually when the testing distance increases; signal strength received on the ceramic title is stronger than on the concrete; the attenuation of signal wave shape received on the concrete is much slower when compared with ceramic title.

Abstract: The cracks-tip field on collinear periodic cracks of infinite orthotropic fiber reinforcement composite plate subjected to anti-plane shear force is studied in this paper. With the introduction of the Westergaard stress function and application of complex function theory and undetermined coefficients method, mechanical problem is changed into partial differential boundary value problem. The undetermined coefficients and the stress function are obtained with the help of boundary conditions. Due to the distribution of periodic cracks, stress intensity factor depends on the shape factor. The results show that interaction happens between the collinear periodic cracks. When the ratio of crack length and crack spacing is less than 1/3, the interaction between the cracks is very small. When the ratio gradually increases to 1, strong interaction between the cracks will be found. Cracks-tip field has scale effect. When the ratio of crack length and the given reference crack length decreases, the displacement field is significantly smaller.

Abstract: The most important factors in hard disk drive suspension manufacturing is the suspension preload, so call “gram load”. The suspensions were generally made from cold rolled stainless steel (SUS304). The suspensions were formed by mechanical forming and gram load was adjusted by mechanical bending until reached a specification. The material properties in mechanical bending simulation of thin stainless steel were usually as isotropic for simple calculation. But the properties of thin stainless steel should be defined as orthotropic materials. Therefore, this work aimed to study gram load results of using isotropic and orthotropic properties. The thin stainless sheet was cut and test for mechanical properties in rolling and transverse directions. The properties of the thin sheet were applied to simulation model. It was found that orthotropic material properties shows a good agreement with the experimental results more than using isotropic material properties. Therefore, the results of this work could be used to explain and predict the mechanical response on the suspension manufacturing.

Abstract: This paper details the design, production and programming methodology of a five degree of freedom robotic arm system. All the hardware and software of the robotic arm have been designed by author and manufactured successfully by CIMS & Robotics Center of Shanghai University. It is the arm of a service robot which is to present the following functions: Chinese calligraphy, carry something from one place to another exactly, and other accurate positioning motion in space. The robotic arm system is based on five orthotropic digital DC brushless servo motors in mechanism, five digital servoamplifier and other devices. Our communication mode is Can-bus, the control software is designed by vb.net2005 language under the .net framework and emulation based on matlab.

Abstract: The Stress field of collinear periodic cracks in an infinite orthotropic composite plate subjected to the concentrated force is studied. The mechanical problem is turned into partial differential boundary value problem. The solution of partial differential equations can be obtained by the complex function methods, which contains unknown coefficients. Using undetermined coefficients method and with the help of boundary conditions, the partial differential boundary value problem is solved. The expressions for stress and displacements near crack tip are derived. Since the distribution of periodic cracks, the stress intensity factor is related to crack shape. Finally, a numerical example shows that the stress changes with the polar angle.

Abstract: Basing on the disadvantages of multi-ribbed slab in practice, a new high-strength steel fiber concrete (HSFC) composite multi-ribbed slab structure is introduced. Because adding steel fibers can improve the capacity of the concrete, it also can make some influence on the mechanic performance of HSFC multi-ribbed slab, such as elastic module, shear module, flexural rigidity, and torsion rigidity and so on. So by the analysis of the material and mechanic capacity and considering the influence of steel fiber, the formulas to calculate flexural rigidity, torsion rigidity, deflection and internal force of the new composite slab are given, in which the multi-ribbed slab is equivalent to orthotropic slab by the principle of stiffness coincidence. The study in this paper can provide some valuable theory references for further study and application of multi-ribbed slab.