Mathematical Modeling of the Stress-Strain State of Adhesive Layers in Sandwich Structures

The studies on theoretical modeling of a sandwich shell (SS) and sandwich beam (SB) are presented in this paper. The displacements of adhesive layers are computed in the whole SS. The Euler-Ostrogradskii equations are used to derive the equations of equilibrium, which contain six 16th-order differential equations. The three-point bending of a sandwich beam is considered and the behavior of the adhesive layer of the SB is calculated.     

Numerical Modeling of Wave Processes in Multilayered Media with Gas-Containing Layers: Comparison of 2D and 3D Models

Doklady Mathematics - Today, the exploration of the Arctic region is one of the most important direction of research in our country, because large amounts of unexplored oil and gas deposits are...     

转捩边界层中次生流向涡演化的数值研究

采用高精度直接数值模拟方法和高效的特征无反射边界条件,进行可压缩流转捩边界层中出现的次生流向涡演化的数值研究.精细的数值模拟结果清楚地揭示了转捩边界层的复杂流场中次生流向涡的形成和演化过程,探讨它对转捩至关重要的环状涡生成的影响,发现次生流向涡和主流向涡的共同作用形成环状涡的一种新机理.     

超音速尖锥边界层中扰动演化特征的数值研究

采用高精度紧致格式, 对超音速尖锥边界层中二维扰动的空间演化, 进行了直接数值模拟．结果表明,虽然尖锥边界层流动存在一定的锥面法向速度,但小扰动的幅值及相位的演化都与由平行流假设得到的线性理论结果吻合．还研究了有限幅值扰动的演化,给出了其演化规律．并在扰动幅值增长到一定值时,发现了小激波．     

粘弹性二阶流体混合层流场拟序结构的数值研究

本文用拟谱方法对随时间发展的二维粘弹性二阶流体混合层流场进行了直接数据值模拟,给出在高雷诺数和低Deborah数下大涡的卷起、配对和合并等过程,通过与相同雷诺数下牛顿流体的比较,揭示了弱粘弹性对混合层中大涡拟序结构演变的影响.     

Numerical Modeling of Functional Fatigue in NiTi Wires

Motivated by the high potential of shape memory alloys (SMA) in several industrial applications, we investigate the material response under cyclic loading. In particular, the focus is set on the modelling of functional fatigue, which results in the deterioration of the specific features of SMA. In fact, functional fatigue restricts SMA in terms of its applicability for real structures and workpieces. This necessitates the development of material models which take this phenomenon into account. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

高弹粘流在三维变厚度狭缝流道中流动的数值模拟

用有限块法对高弹粘流在三维变厚度狭缝流道中的流动进行数值模拟.求出流体流量在流道中的分布规律;通过对实际板材挤出模鱼尾型流道中设置阻流块对流动影响的计算,证实有限块法是简易可行的,从而为挤出模的计算机辅助设计提供了一个重要手段.     

Numerical Modeling Aspects of Dielectric Elastomer Actuators

In modern actuator technology dielectric elastomers are considered as new materials to realize smart actuators which are known as dielectric elastomer actuators (DEAs). In comparison to piezoceramics actuators, DEAs offer the possibility to achieve large deformations with low actuation forces. This property motivates the implementation as artificial muscles since the deformation-force behavior is similar. Other application fields are pumps, deformable surfaces in aerospace, robotics and haptic feedback. The present work introduces the fundamental concepts to describe the electromechanical coupling in the concept of continuum mechanics for finite deformations. As a benchmark a 3D sandwich actuator setup is taken into account to analyze the mechanical compression stability of the elastomer structure, see [1, 2]. This structure is also considered to study the influence of inhomogeneities in the deformation behavior. For this purpose piezoceramic and air inclusions are considered in the finite element mesh. As a last numerical example an elastomer tube with three pairs of electrodes is simulated numerically to motivate the use of dielectric elastomers as peristaltic pumps. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

一类单边约束问题的数值方法

本文分别基于原始变分形式与对偶混合变分形式，对一类单边约束问题进行了数值求解，提出了求解离散对偶混合变分问题的Uzawa型算法，并用数值例子验证了算法的有效性．     

Numerical Modeling of Solitons in a Low Birefringent Optical Fiber

A numerical investigation, based on the split-step Fourier transform algorithm of all optical switching of solitons in a low birefringent optical fiber is presented. The numerical algorithm is described in detail. This revised version was published online in August 2006 with corrections to the Cover Date.     

Modeling and Numerical Simulation of Breaking Waves on Structures

This work deals with the analytical and numerical simulation of the loads on cylindrical offshore structures due to breaking waves. We investigate breaking waves impact on a cylindrical structure on the surface of the water by using a multiphase flow model of immiscible fluids based on the Volume of Fluid (VOF) method. Different numerical schemes are applied to identify the sharp interface between water and gas. The results are compared as well with the already existing experimental, analytical and numerical studies by [1-3]. The agreement shows that the analytical and numerical models are suited to describe the experimental results. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Thermoregulation of Infants: Modeling and Numerical Simulation

A mathematical model is developed and used for a computer simulation of the thermoregulation of premature infants. We propose a finite volume technique for the solution of the associated partial differential equation on an unstructured grid. Emphasis is laid on the model and the validation of the numerical scheme. Beside various test runs using real life data, we present a discrete maximum principle for the steady state solution with respect to the non-convex computational domain.This revised version was published online in October 2005 with corrections to the Cover Date.     

Modeling,Mathematical and Numerical Analysis of Electrorheological Fluids

Many electrorheological fluids are suspensions consisting of solid particles and a carrier oil. If such a suspension is exposed to a strong electric field the effective viscosity increases dramatically. In this paper we first derive a model which captures this behaviour. For the resulting system of equations we then prove local in time existence of strong solutions for large data. For these solutions we finally derive error estimates for a fully implicit time-discretization.     

Numerical Analysis of the Efficiency of Using Theories of Thin and Thick Composite Shells in Stress Concentration Problems

The feasibility of overcoming cutoff effects in four versions of the theory employing classical and mixed functionals is analyzed for sample problems involving the stress concentration near a hole in composite spherical shells with different thicknesses and transverse shear rigidities. Recommendations on the choice of theory are given depending on the shell parameters. A class of not very thick shells with a low shear rigidity is found for which all the versions of the theory yield an acceptable computational accuracy.     

Numerical Modeling of Acoustic Processes in Gradient Media Using the Grid-Characteristic Method

Doklady Mathematics - In this paper, we consider the problem of seismic wave propagation in gradient geological media. Their dynamic behavior is described using the acoustic approximation and the...     

Modeling and Numerical Simulation of Cavitation for Compressible Liquid Flow

A method for the numerical simulation of cavitation phenomena based on the thermodynamic properties of liquid and steam is described. Thereby, a homogeneous cavitation model using a fully compressible discretization technique is considered. The ability of the scheme is proven by numerical experiments.