16 research outputs found
Two-to-one resonant multi-modal dynamics of horizontal/inclined cables. Part I : theoretical formulation and model validation
This paper is first of the two papers dealingwith analytical investigation of resonant multimodal dynamics due to 2:1 internal resonances in the finite-amplitude free vibrations of horizontal/inclined cables. Part I deals with theoretical formulation and validation of the general cable model. Approximate nonlinear partial differential equations of 3-D coupled motion of small sagged cables - which account for both spatio-temporal variation of nonlinear dynamic tension and system asymmetry due to inclined sagged configurations - are presented. A multidimensional Galerkin expansion of the solution ofnonplanar/planar motion is performed, yielding a complete set of system quadratic/cubic coefficients. With the aim of parametrically studying the behavior of horizontal/inclined cables in Part II [25], a second-order asymptotic analysis under planar 2:1 resonance is accomplished by the method of multiple scales. On accounting for higher-order effectsof quadratic/cubic nonlinearities, approximate closed form solutions of nonlinear amplitudes, frequencies and dynamic configurations of resonant nonlinear normal modes reveal the dependence of cable response on resonant/nonresonant modal contributions. Depending on simplifying kinematic modeling and assigned system parameters, approximate horizontal/inclined cable models are thoroughly validated by numerically evaluating statics and non-planar/planar linear/non-linear dynamics against those of the exact model. Moreover, the modal coupling role and contribution of system longitudinal dynamics are discussed for horizontal cables, showing some meaningful effects due to kinematic condensation
āļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāļāļēāļĢāļāļąāļāļāļāļāđāļāđāļāļāļ·āđāļāļŦāļāļēāļāļĩāđāļ§āļēāļāļāļāļāļēāļāļĢāļēāļāļĒāļ·āļāļŦāļĒāļļāđāļāļŦāļĨāļēāļĒāļāļąāđāļāđāļāļĒāļ§āļīāļāļĩāļāļēāļ§āļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđBending Analysis of Thick Plates on a Multi-Layered Elastic Foundation by Boundary Element Method
āļāļāļāļ§āļēāļĄāļāļĩāđāđāļŠāļāļāļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāļāļąāļāļŦāļēāđāļāđāļāļāļ·āđāļāļŦāļāļēāļāļāļāļĄāļīāļāļāđāļĨāļīāļāļ§āļēāļāļāļāļāļēāļāļĢāļēāļāļĒāļ·āļāļŦāļĒāļļāđāļāļŦāļĨāļēāļĒāļāļąāđāļāđāļāļĒāļ§āļīāļāļĩāļāļēāļ§āļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđ (BEM) āļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāļāļąāļāļŦāļēāļāļ°āđāļāđāļŦāļĨāļąāļāļāļēāļĢāļāļāļāļŠāļĄāļāļēāļĢāđāļāļāļ°āļĨāđāļāļ āļāļēāļĄāđāļāļ§āļāļīāļāļāļĩāđ āļŠāļĄāļāļēāļĢāđāļāļīāļāļāļāļļāļāļąāļāļāđāļāļāļāļāļąāļāļŦāļēāđāļāļīāļĄāļāļ°āļāļđāļāđāļāļāļāļĩāđāļāđāļ§āļĒāļŠāļĄāļāļēāļĢāļāļąāļ§āļāļāļāļĩāđāļāļđāļāļāļĢāļ°āļāļģāđāļāļĒāđāļŦāļĨāđāļāļāļģāđāļāļīāļāļŠāļĄāļĄāļāļī āđāļĨāļ°āļĒāļąāļāļāļāđāļāđāđāļāļ·āđāļāļāđāļāļāļĩāđāļāļāļāđāļāļāđāļāļīāļĄ āļāļēāļāļāļąāđāļāļāļĢāļ°āļĒāļļāļāļāđāđāļāđāļ§āļīāļāļĩāļāļēāļ§āļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđāđāļāļ·āđāļāļŠāļĢāđāļēāļāļŠāļĄāļāļēāļĢāļāļĢāļīāļāļąāļāļāđāļāļāļāļāļĨāđāļāļĨāļĒ āđāļĨāļ°āļāļĢāļ°āļĄāļēāļāļāđāļēāđāļŦāļĨāđāļāļāļģāđāļāļīāļāļŠāļĄāļĄāļāļīāļāđāļ§āļĒāļāļāļļāļāļĢāļĄāđāļĢāđāļāļĩāļĒāļĨāđāļāļŠāļīāļŠāļāļąāļāļāđāļāļąāļ āđāļāļāļāļāļ§āļēāļĄāļāļĩāđāđāļĢāđāļāļĩāļĒāļĨāđāļāļŠāļīāļŠāļāļąāļāļāđāļāļąāļāļāļĩāđāđāļāđ āļāļ·āļ Thin Plate Splines; TPS āļāļāļ°āļāļĩāđāđāļāļāļĄāđāļāđāļĄāļāļāļīāļāļāļīāļāļĢāļąāļĨāļāļ°āļāļđāļāđāļāļĨāļāđāļŦāđāđāļāđāļāļāļīāļāļāļīāļāļĢāļąāļĨāļāļĩāđāļāļāļāđāļāļāđāļāļĒāļāļēāļĻāļąāļĒāđāļāļāļāļīāļāļāļāļāļ§āļīāļāļĩāļāļēāļ§āļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđ āļāļĨāđāļāļĨāļĒāļāļāļāļāļąāļāļŦāļēāļāļķāļāļŦāļēāđāļāđāļāļēāļāļŠāļĄāļāļēāļĢāļāļīāļāļāļīāļāļĢāļąāļĨāļāļĩāđāļāļāļāđāļāļāļāļķāđāļāļāļ°āļĄāļĩāļāļēāļĢāđāļāđāļāđāļāļĨāļīāđāļĄāļāļāđāđāļāļāļēāļ°āļāļĩāđāļāļāļāđāļāļāļāļāļāļāļąāļāļŦāļēāđāļāđāļēāļāļąāđāļ āļāļēāļāļāļēāļĢāļĻāļķāļāļĐāļēāļŠāļēāļĄāļēāļĢāļāļŠāļĢāļļāļāļāļĢāļ°āđāļāđāļāļŠāļģāļāļąāļāđāļāđāļāļąāļāļāļĩāđ 1) āļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāđāļāđāļāļāļ·āđāļāđāļāļĒāļ§āļīāļāļĩāļāļēāļ§āļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđāļĄāļĩāļāļ§āļēāļĄāđāļĄāđāļāļĒāļģāļāļĩāđāļĒāļĩāđāļĒāļĄāđāļĄāļ·āđāļāđāļāļĩāļĒāļāļāļąāļāļ§āļīāļāļĩāđāļāļīāļāļ§āļīāđāļāļĢāļēāļ°āļŦāđ 2) āđāļāļ·āđāļāļāđāļāļāļĩāđāļĢāļāļāļĢāļąāļāļŠāđāļāļāļĨāđāļāļĒāļāļĢāļāļāļąāļāļāļĪāļāļīāļāļĢāļĢāļĄāļāļāļāđāļāđāļāļāļ·āđāļāđāļāļ·āđāļāļāļāļēāļāļāđāļēāļāļ§āļēāļĄāđāļāđāļāļāļāļāļāļĩāđāļĢāļāļāļĢāļąāļāļāļĩāđāđāļāļāļāđāļēāļāļāļąāļ 3) āļāļģāļāļ§āļāļāļąāđāļāļāļāļāļāļēāļāļĢāļēāļāļĒāļ·āļāļŦāļĒāļļāđāļāļĄāļĩāļāļīāļāļāļīāļāļĨāļāđāļāļāļĨāļāļēāļĢāļāļģāļāļ§āļāđāļāļīāļāļāļąāļ§āđāļĨāļāļāļāļāļāļēāļĢāļāļāļāļŠāļāļāļāļāļāļāđāļāļĢāļāļŠāļĢāđāļēāļ 4) āđāļāļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāđāļāđāļāļāļ·āđāļāļāļĩāđāļĄāļĩāļĢāļđāļāļĢāđāļēāļāļāļąāļāļāđāļāļ āļāļĨāļāļēāļĢāļāļģāļāļ§āļāļāļēāļāļ§āļīāļāļĩāļāļēāļ§āļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđāļĄāļĩāļāđāļēāļŠāļāļāļāļĨāđāļāļāļāļąāļāđāļāļĢāđāļāļĢāļĄāđāļāđāļāļāđāđāļāļĨāļīāđāļĄāļāļāđIn this paper, an analysis of the Mindlin plate on a multi- layered elastic foundation by Boundary Element Method (BEM) is presented. This analysis employed the principle of the analog equation. According to this concept, the governing differential equations of the original problem are replaced by Poissonâ s equations with fictitious sources under the same boundary conditions. Then the boundary element technique is applied to the established integral equations of solution. The radial basis function series is applied to approximate the fictitious sources. In this work, Thin Plate Splines (TPS) as the radial basis function are chosen. Domain integrals are converted to boundary integrals by employing boundary element technique. Consequently, the solutions of the problem are obtained by boundary integral equation in which the boundary of the problem is only discretized into elements. From this study, the results can be summarized as follows: 1) The results of the plate analyzed by the boundary element method compared with analytical solutions are excellent in terms of accuracy. 2) The boundary conditions directly affect behaviors of the plate structures. 3 ) A number of foundation layers have an influence on numerical results of structural responses. 4) In the analysis of plates with complex shapes, the results from the proposed method are in good agreement with those obtained from the finite element method
Effect of Nanosilica Particle Size on the Water Permeability, Abrasion Resistance, Drying Shrinkage, and Repair Work Properties of Cement Mortar Containing Nano-SiO2
This work presents the effect of nanosilica particle sizes on durability properties and repair work properties of cement mortar containing nanosilica (NS). Three different NS particle sizes of 12, 20, and 40ânm were used and compared with those of cement mortar without NS and cement mortar with silica fume (SF). Interesting results were obtained in which the particle size of NS affected directly the abrasion resistance and water permeability. NS with particle size of 40ânm is the optimum size and gave the highest abrasion resistance and water permeability. For repair work properties, cement mortars containing NS (12 and 20ânm) and SF experienced higher drying shrinkage than that of cement mortar without NS and then presented cracking behavior and debonding between the cement mortars and concrete substrate. Cement mortar containing 40ânm of NS gave the lowest drying shrinkage, the lowest crack number, and the highest adhesive strength. These results indicate that the particle size of NS affected not only the durability properties but also the repair work properties of cement mortar
āļāļēāļĢāļ§āļīāđāļāļĢāļēāļ°āļŦāđāđāļāđāļāļāļ·āđāļāļŦāļāļēāļāļāļāđāļāļāļīāļāđāļāļāļāļāļĢāđāđāļāļāļĢāļāļāļīāļāļāđāļ§āļĒāļ§āļīāļāļĩāļāļēāļ§āļāđāļāļēāļĢāļĩāđāļāļĨāļīāđāļĄāļāļāđAnalysis of Thick Orthotropic Auxetic Plates by Boundary Element Method
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Analysis of a Fractional Variational Problem Associated with Cantilever Beams Subjected to a Uniformly Distributed Load
In this paper, we investigate the existence and uniqueness of minimizers of a fractional variational problem generalized from the energy functional associated with a cantilever beam under a uniformly distributed load. We apply the fractional Euler–Lagrange condition to formulate the minimization problem as a boundary value problem and obtain existence and uniqueness results in both L2 and L∞ settings. Additionally, we characterize the continuous dependence of the minimizers on varying loads in the energy functional. Moreover, an approximate solution is derived via the homotopy perturbation method, which is numerically demonstrated in various examples. The results show that the deformations are larger for smaller orders of the fractional derivative