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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Interaction and multiscale mechanics
Journal Basic Information
Journal DOI :
Editor in Chief :
J. S. Chen / Y.B. Yang / C. S. David Chen
Volume & Issues
Volume 2, Issue 4 - Dec 2009
Volume 2, Issue 3 - Sep 2009
Volume 2, Issue 2 - Jun 2009
Volume 2, Issue 1 - Mar 2009
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Radial basis collocation method for dynamic analysis of axially moving beams
Wang, Lihua ; Chen, Jiun-Shyan ; Hu, Hsin-Yun ;
Interaction and multiscale mechanics, volume 2, issue 4, 2009, Pages 333~352
DOI : 10.12989/imm.2009.2.4.333
We introduce a radial basis collocation method to solve axially moving beam problems which involve
order differentiation in time and
order differentiation in space. The discrete equation is constructed based on the strong form of the governing equation. The employment of multiquadrics radial basis function allows approximation of higher order derivatives in the strong form. Unlike the other approximation functions used in the meshfree methods, such as the moving least-squares approximation,
order derivative of multiquadrics radial basis function is straightforward. We also show that the standard weighted boundary collocation approach for imposition of boundary conditions in static problems yields significant errors in the transient problems. This inaccuracy in dynamic problems can be corrected by a statically condensed semi-discrete equation resulting from an exact imposition of boundary conditions. The effectiveness of this approach is examined in the numerical examples.
Multiscale simulation based on kriging based finite element method
Sommanawat, Wichain ; Kanok-Nukulchai, Worsak ;
Interaction and multiscale mechanics, volume 2, issue 4, 2009, Pages 353~374
DOI : 10.12989/imm.2009.2.4.353
A new seamless multiscale simulation was developed for coupling the continuum model with its molecular dynamics. Kriging-based Finite Element Method (K-FEM) is employed to model the continuum base of the entire domain, while the molecular dynamics (MD) is confined in a localized domain of interest. In the coupling zone, where the MD domain overlaps the continuum model, the overall Hamiltonian is postulated by contributions from the continuum and the molecular overlays, based on a quartic spline scaling parameter. The displacement compatibility in this coupling zone is then enforced by the Lagrange multiplier technique. A multiple-time-step velocity Verlet algorithm is adopted for its time integration. The validation of the present method is reported through numerical tests of one dimensional atomic lattice. The results reveal that at the continuum/MD interface, the commonly reported spurious waves in the literature are effectively eliminated in this study. In addition, the smoothness of the transition from MD to the continuum can be significantly improved by either increasing the size of the coupling zone or expanding the nodal domain of influence associated with K-FEM.
Multiscale modeling of elasto-viscoplastic polycrystals subjected to finite deformations
Matous, Karel ; Maniatty, Antoinette M. ;
Interaction and multiscale mechanics, volume 2, issue 4, 2009, Pages 375~396
DOI : 10.12989/imm.2009.2.4.375
In the present work, the elasto-viscoplastic behavior, interactions between grains, and the texture evolution in polycrystalline materials subjected to finite deformations are modeled using a multiscale analysis procedure within a finite element framework. Computational homogenization is used to relate the grain (meso) scale to the macroscale. Specifically, a polycrystal is modeled by a material representative volume element (RVE) consisting of an aggregate of grains, and a periodic distribution of such unit cells is considered to describe material behavior locally on the macroscale. The elastic behavior is defined by a hyperelastic potential, and the viscoplastic response is modeled by a simple power law complemented by a work hardening equation. The finite element framework is based on a Lagrangian formulation, where a kinematic split of the deformation gradient into volume preserving and volumetric parts together with a three-field form of the Hu-Washizu variational principle is adopted to create a stable finite element method. Examples involving simple deformations of an aluminum alloy are modeled to predict inhomogeneous fields on the grain scale, and the macroscopic effective stress-strain curve and texture evolution are compared to those obtained using both upper and lower bound models.
Building frame-pile foundation-soil interactive analysis
Chore, H.S. ; Ingle, R.K. ; Sawant, V.A. ;
Interaction and multiscale mechanics, volume 2, issue 4, 2009, Pages 397~411
DOI : 10.12989/imm.2009.2.4.397
The effect of soil-structure interaction on a simple single storeyed and two bay space frame resting on a pile group embedded in the cohesive soil (clay) with flexible cap is examined in this paper. For this purpose, a more rational approach is resorted to using the three dimensional finite element analysis with realistic assumptions. The members of the superstructure and substructure are descretized using 20 node isoparametric continuum elements while the interface between the soil and pile is modeled using 16 node isoparametric interface elements. Owing to viability in terms of computational resources and memory requirement, the approach of uncoupled analysis is generally preferred to coupled analysis of the system. However, an interactive analysis of the system is presented in this paper where the building frame and pile foundation are considered as a single compatible unit. This study is focused on the interaction between the pile cap and underlying soil. In the parametric study conducted using the coupled analysis, the effect of pile spacing in a pile group and configuration of the pile group is evaluated on the response of superstructure. The responses of the superstructure considered include the displacement at top of the frame and moments in the superstructure columns. The effect of soil-structure interaction is found to be quite significant for the type of foundation used in the study. The percentage variation in the values of displacement obtained using the coupled and uncoupled analysis is found in the range of 4-17 and that for the moment in the range of 3-10. A reasonable agreement is observed in the results obtained using either approach.
Displacements of the helical stator tooth for an electromechanical integrated toroidal drive
Xu, Lizhong ; Zheng, Dazhou ;
Interaction and multiscale mechanics, volume 2, issue 4, 2009, Pages 413~430
DOI : 10.12989/imm.2009.2.4.413
The stator tooth is a key component of the electromechanical integrated toroidal drive system. The stator tooth is spiral in shape and the calculation of its displacements is difficult. In this paper, using the coordinate transformation method, the displacements of the stator tooth in the local coordinate system are expressed as the function of the variable in the drive coordinate system. Using the minimum potential energy principle, the equations of the displacements of the stator tooth under the loads are deduced. The displacement distributions within the stator tooth are investigated and the changes of the displacement distributions along with the main parameters are analyzed. This research can offer the basis for the strength and stiffness design of the drive system.
The influence of different support movements and heights of piers on the dynamic behavior of bridges -Part I: Earthquake acting transversely to the deck
Michaltsos, George T. ; Raftoyiannis, Ioannis G. ;
Interaction and multiscale mechanics, volume 2, issue 4, 2009, Pages 431~454
DOI : 10.12989/imm.2009.2.4.431
This paper presents a simple model for studying the dynamic response of multi-span bridges resting on piers with different heights and subjected to earthquake forces acting transversely to the bridge, but varying spatially along its length. The analysis is carried out using the modal superposition technique, while the solution of the resulting integral-differential equations is obtained via the Laplace transformation. It has been found that the piers' height and the quality of the foundation soil can affect significantly the dynamic behavior of such bridges. Typical examples showing the effectiveness of the method are presented with useful results listed.