Volume 15, Issue 5

This paper deals with analysis of the mechanical behavior of an electro-statically-actuated micro-beam resonator from the bifurcation view of point. The non-local constitutive relation has been used to obtain the governing deformation equations. The obtained static equation has been solved using two approaches. The dynamic equation of motion has been solved applying a Galerkin-reduced order model. Bifurcation behavior of the beam subjected to an electrostatic force has been analyzed using the both approaches. The fixed points of the beam for given voltages have been obtained and stability of them determined by studying the phase portraits for each fixed point.

This paper deals with the detailed analysis and discussion of nonlinear static analysis of a laminated composite plate subjected to uniform pressure load. Governing equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a simply supported plate are assumed for the plate domain. The single term approximation functions are selected by considering the nonlinear static deformations of plate. The solution is obtained using the Newmark method in MATLAB software. The plate is also modeled and analyzed using ANSYS software using SHELL91 elements. The variation of membrane, linear and nonlinear bending terms are obtained along a characteristic line on the plate and the numerical and finite element results are compared. The results are discussed in detail considering the nonlinear static behavior of the laminated composite plate and the main reasons of discrepancies are discussed. Dynamic behavior of the plate is explained considering the nonlinear static behavior.

Applying multifractal centered moving average and two graph based analysis, we investigate and compare statistical behaviors of return time series of some Chinese market data and a financial model developed by the continuum percolation system. The local interaction or influence among traders in the actual market is constructed by the continuum percolation, and a cluster of continuum percolation is applied to define the cluster of traders sharing the same opinion about the market. The empirical research shows that the simulation data of the model exhibits fractal and multifractal features. Further, we find that the degree distribution of visibility graph for the simulation series has power-law tails, and the corresponding mean path length growth shows the “small-world” effect. All these features are in agreement with real market data.

A finite-difference scheme by using general quadrilateral cells was developed, and a method of quarter integration path was proposed and was applied in the calculation of node forces. By using the technique of finite-volume and Green's integration formula, the finite-difference equations were obtained, and the equations were programmed by using VB.NET program language, and a code DMFD was developed. By using this code, a P-wave propagating along a finite-length rock bar was simulated, and the numerical results agree very well with the theoretical results as well as the results from ABAQUS code. Finally, the in-situ blasting in a hydropower station was simulated by using DMFD code, and the results generally agree with the in-situ results as well as those predicted by UDEC code.

In this study, we present and apply a new, accurate and easy to implement numerical method to realize and verify the synchronization between two identical chaotic Lorenz, Genesio-Tesi, Rössler, Chen and Rikitake systems. The proposed method is called the multi-stage spectral relaxation method (MSRM). We utilize the active control technique for the synchronization of these systems. To illustrate the effectiveness of the method, simulation results are presented and compared with results obtained using the Runge-Kutta (4, 5) based MATLAB solver, ode45.

A kind of mesoscopic reaction rate model is reexamined in this paper with the aim of getting rid of the temperature dependence of its experiential parameters and making it available to predict the shock initiation of solid explosives under different initial temperatures. It is found that the initial temperature effect is induced mainly by the temperature dependence of the local chemical reaction rate and the initial density of the explosives, and, via the introduction of such temperature dependence, the reaction rate model can predict well the shock initiation processes under different initial temperatures, in which just the experiential parameters under a certain temperature (e.g. the normal temperature) are needed. Moreover, for verification, the shock initiation processes of PBX-9501 under different initial temperatures were simulated numerically by using the DYNA2D software. The numerical results on the run distance to detonation are found to be in good agreement with previous experimental data.

In this work, we describe a numerical method which enables an efficient computation of membrane gas permeation processes that involve multiple membrane stages and multiple gas components. The utilized numerical approach is a collocation method equipped with a grid adaptation strategy based on a dependable error estimate of the numerical approximation. The comparison of the results provided by the collocation method with those calculated from an experimentally validated finite difference method has demonstrated, that the accuracy of both numerical approximations is practically the same. However, the current procedure is characterized by a much better computational efficiency that allows to considerably reduce the computational time. This is a crucial feature when combining computation of membrane permeation processes with optimization algorithms. In such a setting the computation of the permeation process is frequently repeated and naturally, results in long computational times when the efficiency is not adequately improved.

A new method is proposed to perform the multiscale simulation of nanoindentation with wedge indenter. We designed a potential field to model the wedge indenter based on the repulsive force-field approach which was used to model round indenters. A smooth curve representing the indenter tip is used to avoid the singularity of an ideal wedge indenter. Simulation with our approach correctly shows essential features of wedge nanoindentation. The load responses during retraction is confirmed by elastic model based on the Oliver–Pharr approach. Significant indentation size effect that the contact hardness decreases with the increase of contact depth is compared with existing models. The atomic configurations of the film shows that perfect dislocations nucleate under the indenter with Burges vectors perpendicular to the indentation direction. The strain distribution under the indenter shows that the length of plastic zone in the indentation direction is much larger than the contact width.

With the addition CNTs, the properties of SnAgCu solders and solder joints can be improved remarkably. In this paper, based on the creep testing, the Dorn creep model was used to represent the creep behavior of SnAgCuCNT solder, and the parameters were determined with the fitting analysis. Moreover, the Dorn creep model of SnAgCu and SnAgCuCNT was incorporated into finite element code for calculating the creep strain response of solder joints in FCBGA (Flip Chip Ball Grid Array) device during thermal cycle loading. The results indicated that the CNTs can enhance the creep resistance of SnAgCu solder, which demonstrates the SnAgCuCNT solders can replace the SnAgCu solder in electronic industry for highreliability requirement.