Element Scheme Research Articles

Simulation of Moisture Ingress in Concrete Subjected to Intermittent Rainfall in a Composite Tropical Climate

The study of moisture movement in concrete under the influence of a service environment is vital for the assessment of its probable degradation. An aspect of significance in this regard is the delineation of the near-surface depth, which remains exposed to moisture penetration. The influence of invading moisture renders the reinforcement laid within this zone vulnerable to the risk of corrosion, known to be the most prevalent cause of premature distress in reinforced concrete elements. This study analyses numerically the phenomenon of moisture ingress in concrete subjected to intermittent rainfall events—an exposure typical of tropical climates. The exposure scenarios considered in this study pertain to the composite tropical climate of New Delhi (India) and have been quantified based on the statistical analysis of 15 years’ rainfall data. The moisture transport process in an unsaturated concrete medium has been represented with a modified form of Richard’s equation. Analysis of the modified model has been carried out using a transient, non-linear, one-dimensional finite element (FE) scheme. A simulation of the moisture ingress phenomena has been demonstrated by adopting relevant material properties from the published literature. Observations reveal that a depth of 20 to 55 mm in exposed concrete remains susceptible to the ingress of water under the influence of extreme rainfall conditions.

Ионно-молекулярная модель памяти. Потенциальные источники, детекторы, передатчики и накопители информации

This paper deals with the important issues of the developed model of memory, namely: basic elements of functional scheme of ion-molecular model: potential sources, transmitters, detectors, mass storage media by means of radio-physical analogy. It was established that neurons are structural elements of memory. The question of the role of cash and new proteins in the organization of memory was considered. Without a doubt, that in the process of transfer and accumulation of information is the activation of protein synthesis. Definitions of the source, detector, transmitter and drive information in their biological, biophysical interpretations were given. It is about a multi-element information system. It is clear that from the position of the conceptual model of memory, as originally postulated, opens a wide field for discussion. The below is an element of the hierarchical tree of memory, the more difficult it becomes positively identify him. But any new theory invariably goes through this stage. Detailed scheme of subordination elements of the system of receiving information on ionic and molecular carriers of memory was presented. In the end of this paper a substantial question was considered: is it possible to store all the received information, limited only by the time of functioning (existence) of the body? On the basis of the analysis of literary sources and in the context of developing the authors of ion-molecular memory model answer to the question can be the following: the concept of the possibility of such information storage if there is, obviously, only in that case when there are no structural changes in the library memory.

Modeling of chemical mechanical polishing processes by cellular automata and finite element/matlab integration methods

In this work, novel chemical-mechanical polishing modeling schemes in both wafer and device levels are proposed and analyzed. The cellular automata method, based on Preston equation and contact mechanics, are used for analyzing the wafer level material removing rate. On the other hand, a finite element and Matlab integration scheme is also developed, primarily for addressing the structural integrity of interconnected structures after polishing. These methods are validated by comparing the previous reported analysis and experimental data. Finally, these schemes are used for parametric studies for guiding process optimization.

Iterative solution methods for mesh approximation of control and state constrained optimal control problem with observation in a part of the domain

Iterative solution methods for finite-dimensional constrained saddle point problems are investigated theoretically and numerically. These saddle point problems arise when approximating differential optimal control problems with point-wise state and control constraints by finite element or finite difference schemes with further using Lagrange multipliers technique. The linear elliptic boundary value problems with distributed control and the observation in a part of the domain are considered. Equivalent transformations of the constructed finite-dimensional saddle point problem are executed to apply effectively Uzawa-type iterative methods. Numerical comparison of these methods with gradient method for a regularized problem and interior point method is done.

Application range of internal dumping in opencast mining of steep mineral deposits

Under discussion are the issues of driving secondary access roadways without pushing ultimate pitwall limits in steep deposits with internal dumping. The calculation scheme and correlation analysis of key elements of the resource-saving technology are presented. Regressional relationships are obtained for length of an open pit mine bottom, specific weight of internal dumping and the open pit mine parameters. The article specifies the effective range of the developed technology.

Структура и состав системотехнической модели устойчивого развития инвестиционно-строительной деятельности

This article discusses the background and aspects of model management of investment and construction activities (ICA) in order to optimize its processes. This system is designed for efficient management and balanced increase of work amount in the construction, reconstruction and renovation of facilities. The model is based on a systematic approach and the principles of integrated planned development, taking into account the requirements of saving energy and resources, environment, organizational and technical reliability and socio-political stability. Due to the nature of construction operations, as well as the connections with the parameters of sustainable development of the ICA, techno-economic system is characterized as a set of three main functional groups of subsystems: analysis and synthesis, main and auxiliary executive subsystems, resulting subsystems. The interaction of the elements of ICA is investigated: streams of resources and information arising in the course of implementation of projects. Within the article the schemes of functional elements of the ICA system with the description of their interrelations are presented. The systems engineering model of the ICA sustainable development is offered.

The Study of Explicit Scheme of Hybrid Stress-Function Element with Rotation Degrees of Freedom

A simple and efficient explicit scheme of triangular planar element with rotation degrees of freedom is proposed in this paper. The basic fundamental solutions of plane elasticity problem based on Airy stress functions are used as trial functions to construct triangular element with drilling degrees of freedom. During the construction of element model, the explicit expression of element stiffness matrix is deduced by means of triangular area coordinates integration method, instead of numerical integration method. Numerical calculation indicates that the element constructed in this paper is of high precision but less computational cost.

The dynamic response of edge clamped plates loaded by spherically expanding sand shells

The dynamic deformation of both edge clamped stainless steel sandwich panels with a pyramidal truss core and equal mass monolithic plates loaded by spherically expanding shells of dry and water saturated sand has been investigated, both experimentally and via a particle based simulation methodology. The spherically expanding sand shell is generated by detonating a sphere of explosive surrounded by a shell of either dry or water saturated synthetic sand. The measurements show that the sandwich panel and plate deflections decrease with increasing stand-off between the center of the charge and the front of the test structures. Moreover, for the same charge and sand mass, the deflections of the plates are significantly higher in the water saturated sand case compared to that of dry sand. For a given stand-off, the mid-span deflection of the sandwich panel rear faces was substantially less than that of the corresponding monolithic plate for both the dry and water saturated sand cases. The experiments were simulated via a coupled discrete-particle/finite element scheme wherein the high velocity impacting sand is modeled by interacting particles while the plate is modeled within a Lagrangian finite element setting. The simulations are in good agreement with the measurements for the dry sand impact of both the monolithic and sandwich structures. However, the simulations underestimate the effect of stand-off in the case of the water saturated sand explosion, i.e. the deflections decrease more sharply with increasing stand-off in the experiments compared to the simulations. The simulations reveal that the momentum transmitted into the sandwich and monolithic plate structures by the sand shell is approximately the same, consistent with a small fluid–structure interaction effect. The smaller deflection of the sandwich panels is therefore primarily due to the higher bending strength of sandwich structures.

Delays of schemes in a model that considers the input values of functional elements

A delay model for schemes of functional elements in arbitrary finite complete basis B is studied; in the model, delays of the basic element are given by random positive real numbers for each input and each input set of variables entering other inputs. Asymptotic estimates in the form τB n ± O(logn), where τB is a constant that depends only on basis B, are obtained for the delay of the multiplex function of order n. Based on these estimates, asymptotic estimates of the form τB n ± O(logn) for the corresponding Shannon function, i.e., for the delay of the worst function of logic algebra that depends on given n variables, are established.

A Two-Grid Method of Nonconforming Element Based on the Shifted-Inverse Power Method for the Steklov Eigenvalue Problem

This paper establishes a new kind of two-grid discretization scheme of nonconforming Crouzeix-Raviart element based on the shifted-inverse power method for the Steklov eigenvalue problem. The error estimates are provided from the work of Yang and Bi (SIAM J. Numer. Anal., 49, pp.1602-1624, 2011). Finally, numerical experiments are reported to illustrate the high efficiency of the two-grid discretization scheme proposed in this paper.

An improved CE/SE scheme for incompressible multiphase flows and its applications

A new space-time conservation element-solution element (CE/SE) scheme, which is based on the hexahedron mesh, is proposed by constructing a new structure of solution elements (SEs) and conservation elements (CEs) and extended to two-dimensional incompressible multiphase flows. This scheme is applied to several incompressible flow problems, such as lid-driven cavity flow, dam break flow, motions of falling droplets, flow instability and water-kerosene interaction. The numerical results and their comparison with lecture results and experimental data are presented. The comparisons demonstrate that the computational scheme developed currently is clear in physical concept, easy to be implemented and highly accurate and efficient for the above-mentioned problems. The highlight is that the pretreatment method is proposed, transforming the elliptic-parabolic equations to the hyperbolic equations, which can be directly simulated by the improved CE/SE scheme. Thus, the improved CE/SE scheme can be applied to incompressible multiphase flows widely.

Исследование гуманистического аспекта в патриотическом воспитании студентов

Authors point of view of the students patriotic education in the universities from a position of humanization of education is based in this article. At the correlation of principle scheme of the component elements of the patriotic upbringing at the university and alteration which have take place at the personality it possibly to present the following manner: self cognition – self relation – self definition – self realization.

An iterative method for mixed finite element schemes

An iterative method with a saddle preconditioner is proposed for solving a system of nonlinear equations that arises in the approximation of a quasilinear second-order elliptic equation with a mixed scheme of finite elements of Raviart-Thomas type. The ways of choosing the iteration parameter are pointed out that ensure the convergence of the method. The results of numerical experiments are presented.

Uncertain Out-of-Plane Behavior of Composite Plates due to Spatially Random Material Properties

This paper deals with the evaluation of response variability of composite plates due to randomness in the Poisson’s ratio in particular for the out-of-plane behavior. To this end, we adopt the weighted integral stochastic finite element (SFE) scheme and derive a SFE formulation employing Taylor’s expansion on the random Poisson’s ratio and displacement vector as well. In case of composite plates, the stiffness of the structure is affected by the stacking scheme of individual layers. This means that even the plates subjected only to in-plane loading can show out-of-plane behavior. In order to investigate this phenomenon, we chose two example plates with symmetric and asymmetric stacking scheme. A detailed explanation on the results is addressed for the plates under consideration.

Space time CE/SE and discrete ordinate method for solving gas flows of arbitrary statistics

A novel deterministic solver for solving rarefied flow of gases of arbitrary statistics is developed based on semiclassical Boltzmann-BGK equation. The discrete ordinate method is firstly applied to discretize the velocity space resulting in a set of hyperbolic equations with source terms which are to be carried out using conservation element/solution element scheme. The method is tested on one-dimensional shock tube problems.

A superconvergent scheme for a locking‐free FEM in a Timoshenko optimal control problem

AbstractIn this work we analyze the numerical approximation of an optimal control problem of a Timoshenko beam, by considering two kinds of distributed control. The discretization of the control variables is performed by using piecewise constant functions. The states and the adjoint states are approximated by a locking free scheme of linear finite elements. An interpolation postprocessing technique is used for the approximations of the optimal solution of the continuous optimal control problem. It is proved that these approximations have superconvergence order h2, which do not depend on the thickness of the beam.

Dynamic delamination of patterned thin films: a numerical study

We present an analytical investigation of a test protocol recently developed to extract the fracture toughness of thin films used in microelectronics and other engineering applications. The testing method involves the dynamic delamination of patterned thin films initiated by a laser-induced pressure pulse applied on the backside of the substrate. The kinetic energy imparted by the pulse to a weakly bonded (pre-cracked) region of the film is converted into fracture energy as the thin film delaminates in a controlled fashion over multiple milimeters. To support these experiments and extract the interface fracture toughness values, we develop a numerical scheme based on the combination of a nonlinear beam model used to capture the elastodynamic response of the thin film and a cohesive failure model to simulate the spontaneous propagation of the delamination front. The accuracy of the beam model is assessed through a comparison with the results of a more complex 2D hybrid spectral/finite element scheme. Numerical results are compared with experimental measurements of the delamination length and the outcome of a parametric study of some of the key geometrical and loading quantities defining the delamination event is presented.

P-Cyclic SOR for BVPs with periodic boundary conditions

The employment of finite element or finite difference discretization schemes, for the numerical solution of Boundary Value Problems (BVPs) with periodic type Boundary Conditions (BCs), leads to a large and sparse linear system whose coefficient matrix is in normal p-cyclic form. The use of block iterative methods, for the solution of such linear systems, and the demand for fast convergence rates, require the optimal repartitioning of the coefficient matrix. In this work, we make use of the finite element Hermite collocation method to discretize the BVP and the SOR iterative method to solve the corresponding sparse linear system. The optimal repartitioning of the collocation coefficient matrix leads to SOR methods with optimal rates of convergence.

Asymptotically minimal schemes for one sequence of Boolean functions

Monotone symmetric Boolean functions \( f_2^n (\tilde x) = \mathop \vee \limits_{1 \leqslant i < j \leqslant n} x_i x_j \) are considered. For such functions, the asymptotics L B (f 2 n ) ∼ 3n, where L B (f 2 n ) is the complexity of realization of function f 2 n by schemes of functional elements in the basis B = {&, −}, is established.

A lumped mass nonconforming finite element method for nonlinear parabolic integro-differential equations on anisotropic meshes

A lumped mass approximation scheme of a low order Crouzeix-Raviart type nonconforming triangular finite element is proposed to a kind of nonlinear parabolic integro-differential equations. The L2 error estimate is derived on anisotropic meshes without referring to the traditional nonclassical elliptic projection.