Papers by Keyword: Orthotropic

Abstract: Considering xz plane heterogeneous mechanical properties and thermal-pressure loads, thermoelastic analysis is applied on orthotropic nose cap of a hypersonic vehicle in the flight trajectory. The results show that the thermal-stress of sphere section presents annular, the Mises equivalent stress is of periodicity of 90° in tail so obviously that a reasonable connection is important. Finally, two connections, bolted and plug connection, are considered to relax the overnice tail constrains, and the results show that the plug connection is reasonable for the hypersonic heterogeneous orthotropic nose cap

Abstract: Abstract Based on the thin plate theory and the transfer matrix method, the vibration propagation in periodical orthotropic single-leaf rib-stiffened panels is studied. The localization factors of the ordered and disordered periodic systems are calculated. The numerical results show that the anisotropy of the plate affects the propagation of vibration in the pannels. With the relative bending rigidity increasing, or with the relative torsional rigidity increasing, the width of stopbands increases in low dimenionless frequencies. The vibration localization phenomenon occurs in the span-length disordered periodic structures and it is enhanced with the increasing disorder of span-length.

Abstract: In the rockfall protection barriers, the role of the net is to diffuse the efforts to the braking devices which absorb the energy and slow down the velocity of the block. An innovative braking device working by the buckling of metallic tubes is developed by quasi-static and dynamic tests. Real scale experiments on the entire structure are done and presented here. These tests are performed as the recommendations of the new Guideline for European Technical Approval concerning the falling rock protection kits, named ETAG 27.

Abstract: Stiffened plate is a common structure form in plate and shell structure. There are important theoretical significance and project application value on studying dynamic response of stiffened plate subjected to air explosive loading. The motion equation of orthotropic plate which subjected to explosive loading is established adopting Lagrange’s equation of motion, and the stiffened plate where the stiffener is arranged uniformly is treated as textural orthotropic plate. Then the motion equation of the orthotropic plate is converted into motion equation of the stiffened plate. Therefore the maximum deformation of stiffened plate can be determined.

Abstract: In order to improve long-term durability of bioprosthetic heart valve, we take the spherical,paraboloidal,cylindrical and the ellipsoidal leaflets for nonlinear analysis and the material is orthotropic.The experimental results of the finite element nonlinear analysis show that when the leaflets with the material orthotropic is closed,the deformation of the symmetric edge is larger than else. The stress distribution of the cylindrical, spherical, paraboloidal and ellipsoidal valve leaflets is quite different. The ellipsoidal valve leaflets have more advantages than the cylindrical, spherical, paraboloidal valve leaflets.This work is very helpful to manufacture reasonable shaped valvular leaflets and to prolong the lifetime of the bioprosthetic heart valve.

Abstract: The orthotropic mechanical behaviors of weft-knitted flax fiber fabric reinforced polypropylene (PP) composites, which were produced by hot pressing of knit layers composed of a commingled yarn with a flax fiber content of 50vol.%, are investigated in both meso- and macro-scales. In meso-scale, the repeating unit cell (RUC) finite element (FE) model is developed, in which impregnated yarns are assumed to be isotropic elastic while the matrix is modeled as an elastoplastic, isotropic solid. Then, stress-strain curves of the RUC are simulated for its elastoplastic orthotropic parameters. Finally, in macro-scale of its specimen, the tensile behavior of the composite laminates with six parallel plies is simulated by means of 3D elastoplastic FE method. The applicability and limitation of this model have been discussed.

Abstract: This paper is concerned in semi-infinite interface crack of orthotropic and isotropic bi-materials and using the composite material fracture complex function method. By means of constructing special stress functions with two real singularity index and solving the problem of a class of generalized bi-harmonic equations , the stress and displacement fields of two dissimilar materials are obtained .Results demonstrate that the stress and displacement fields near the crack tip show mixed crack characteristics without oscillation.

Abstract: This paper reviewed the research on the vibration of orthotropic circular membrane. We applied the large deflection theory of membrane and principle of virtual displacement to derive the governing vibration equations of circular membrane, solved it, and obtained the power series formula of nonlinear vibration frequency of circular membrane with all edges fixed. The paper gave the computational example and compared the frequency with different initial displacements, respectively. Results obtained from this paper provide some theoretical foundation for the research of orthotropic composite materials; meanwhile, the results provide some theoretical foundation for the research of nonlinear vibration of membrane.

Abstract: A full scale model of orthotropic deck panel was designed and fabricated referring to the common steel box girder bridges used in China. Experiment was conducted to test the behavior and fatigue performance of the orthotropic steel bridge deck under the actual truck wheel load. The loading test was conducted on the platform specially prepared. Measurement of the over-all structure and the fatigue sensitive details was made to evaluate the performance of the panel. For each gauge position, the results are presented as the form of influence lines.

Abstract: The cracks-tip field on ModeⅡperiodic cracks of infinite orthotropic fiber reinforcement composite plate subjected to the concentrated force was studied. 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. Owing to the distribution of periodic cracks, stress intensity factor(SIF) depends on the shape factor, which is greatly influenced by the crack spacing and the crack length. The results show that interaction happens between the periodic cracks, and that scale effect of the stress intensity factor in cracks-tip is obvious.