Does a Staggered Scheme Pay Off on Large-scale Hydraulic-mechanical Simulations?

2021 ◽  
Author(s):  
Dominik Kern ◽  
Fabien Magri ◽  
Victor Malkovsky ◽  
Thomas Nagel
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Order Approximation ◽  
Coupled Systems ◽  
Scale Model ◽  
Strongly Coupled ◽  
Spatial Dimensions ◽  
Long Time ◽  
And Performance ◽  
Monolithic Approach

<p>From previous studies it is evident that decoupled simulations lack the ability to capture certain coupled effects, such as the Noordbergum effect or the Mandel-Cryer effect in a hydraulic-mechanical context. Thus, for detailed simulations of geotechnical or geological system, coupled simulations are usually chosen. For example, thermal-hydraulic-mechanical (THM) coupled systems, and even chemical and biological couplings (THMCB), are considered in simulations used to assess barrier integrity over long time spans in the context of geological waste disposal.</p><p>This paper is restricted to coupled hydraulic-mechanical (HM) systems. A monolithic approach is both stable and accurate for strongly coupled systems. However, as site-scale models of geological disposal facilities are also large in spatial dimensions, it is worth to investigate how staggered methods may cut down the computational costs. The fixed-stress split appears to be a promising approach for staggered schemes in terms of stability, consistency, accuracy, and efficiency.</p><p>While adding another iteration level in comparison to monolithic schemes, staggered schemes allow for lower-order approximation spaces, whereas monolithic schemes require Taylor-Hood elements resulting in a larger number of degrees of freedom per element. Both coupling schemes are implemented in the the open-source finite-element (FE) software OpenGeoSys and used to simulate a large-scale model, which is oriented towards a real site in planning in Russia. Simulation results are compared in terms of accuracy, coupling effects and performance.</p>

Atomic Kinetics and Dynamical Phason Disorder in a Quasicrystal

1995 ◽  
Vol 407 ◽  
Author(s):  
M. Dzugutov
Keyword(s):  
Degrees Of Freedom ◽  
Coupled Systems ◽  
Atomic Diffusion ◽  
Relaxation Dynamics ◽  
Strongly Coupled ◽  
Stretched Exponential ◽  
Intermediate Scattering Function ◽  
Microscopic Interpretation ◽  
Exponential Behaviour ◽  
Atomic Kinetics

ABSTRACTSlow relaxation dynamics in strongly coupled systems is known to be universally described by the stretched exponential Kohlrausch law. However, this phenomenon, observed in various condensed systems, still eludes a comprehensive microscopic interpretation. I discuss here the relaxation dynamics in an equilibrium dodecagonal quasicrystal which demonstrates a pronounced stretched exponential behaviour. The quasicrystal, simulated by Molecular Dynamics, reveals the presence of dynamical phason disorder, a generic form of relaxation dynamics associated with incommensurate, or phason degrees of freedom. This dynamics brings about a novel form of atomic diffusion, which is examined here by calculating the self part of intermediate scattering function Fs(Q, t). The latter displays a non-exponential decay which is found to be described by the Kohlrausch law with the stretching exponent β = 0.47. I discuss here a possible similarity between the dynamics of quasicrystals observed and that of supercooled liquids and glasses.

Multiharmonic Response Analysis of Systems With Local Nonlinearities Based on Describing Functions and Linear Receptance

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
F. Wei ◽  
G. T. Zheng
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Time Integration ◽  
Computational Cost ◽  
Kinetic Equations ◽  
Computational Effort ◽  
Response Analysis ◽  
Algebraic Equations ◽  
Describing Functions ◽  
And Performance

Direct time integration methods are usually applied to determine the dynamic response of systems with local nonlinearities. Nevertheless, these methods are computationally expensive to predict the steady state response. To significantly reduce the computational effort, a new approach is proposed for the multiharmonic response analysis of dynamical systems with local nonlinearities. The approach is based on the describing function (DF) method and linear receptance data. With the DF method, the kinetic equations are converted into a set of complex algebraic equations. By using the linear receptance data, the dimension of the complex algebraic equations, which should be solved iteratively, are only related to nonlinear degrees of freedom (DOFs). A cantilever beam with a local nonlinear element is presented to show the procedure and performance of the proposed approach. The approach can greatly reduce the size and computational cost of the problem. Thus, it can be applicable to large-scale systems with local nonlinearities.

scholarly journals A comparison of second-order model order reduction methods for an artificial fishtail

2019 ◽  
Vol 67 (8) ◽  
pp. 648-667 ◽  
Author(s):  
Jens Saak ◽  
Dirk Siebelts ◽  
Steffen W. R. Werner
Keyword(s):  
Model Order Reduction ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Order Reduction ◽  
Second Order ◽  
Scale Model ◽  
Order Model ◽  
Model Order ◽  
Reduction Methods ◽  
Second Order Model

Abstract In order to apply control theory in small autonomous vehicles, mathematical models with small numbers of states are required for using the limited computational power in embedded programming. In this paper, we consider an artificial fishtail as an example for a complex mechanical system with a second-order large-scale model, which is derived by using the finite element method. To meet the above limitations, the several hundreds of thousands of degrees of freedom need to be reduced to merely a handful of surrogate degrees of freedom. We seek to achieve this task by various second-order model order reduction methods. All methods are applied on the fishtail’s matrices and their results are evaluated and compared in the frequency domain as well as in the time domain.

Optimization for Vibration Reduction in Final Phase of Automotive Body Structural Design

2001 ◽  
Author(s):  
Yasuaki Tsurumi ◽  
Toshiaki Nakagawa ◽  
Nobuyuki Mori ◽  
Hiroshi Yamakawa
Keyword(s):  
Structural Design ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Design Method ◽  
Element Model ◽  
Performance Criteria ◽  
Scale Model ◽  
Automotive Body ◽  
Large Scale Model ◽  
Noise Vibration

Abstract In automotive body structural design, Computer Aided Engineering (CAE) has been widely used in order to evaluate noise, vibration, harshness (NVH). A CAE engineer has usually used a large-scale finite element model exceeding 1 million degrees of freedom to improve NVH performance criteria in the final design phase. It is, however, difficult for a CAE engineer to propose the modification candidate for the NVH reduction to an automotive designer in the phase, while good accuracy of the analysis is obtained by using the large-scale model. Only the small modifications can be performed for the NVH performance since configurations of main frame structures are usually determined with respect to crashworthiness in the phase. Therefore, a CAE engineer cannot provide the designer with effective information on time. In this paper, a new optimal design method using a reduction scheme based on the physical coordinates under many design constraints regarding the crashworthiness is proposed in order to overcome above problems. Our proposed method finds out an optimal layout and stiffness value efficiently from the calculation results of the large-scale model. That is, we determine the appropriate location and additional scalar spring constants by minimizing the acceleration of the observation grid. The effectiveness and availability of this method are confirmed using an example.

Research on High-Quality Soft Shadow of Building Based Shadow Map

2012 ◽  
Vol 174-177 ◽  
pp. 1927-1930 ◽  
Author(s):  
Tao Shang ◽  
Shui Peng Zhang
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Data Sets ◽  
Depth Data ◽  
Soft Shadow ◽  
Shadow Map ◽  
Long Time ◽  
Depth Buffer ◽  
And Performance ◽  
The One

Image rendering of shadow faces a problem existed for a long time,that is the contradiction of quality and performance. Variant algorithms are presented to ameliorate this problem,shadow map is the one which is representative for that. Even though shadow maps have been widely used for the shadow of Three-dimensional scene,some imperfection still exist in this method like aliasing problem.So,the focus of the paper is introduce an algorithm which layering the data sets of the large scale building's shadow rapidly and intelligently based shadow map. First, we ascertain the fragment which create the shadow by shadow mapping's two scan. Second, we process the float data in the depth buffer by using uniformization and render the two depth data in the texture.Then use Gauss Filter to blur.Finally,use the algorithm of BIRCH cluster the uniformization data to improve the obscure and tweened effect.This method brings reduction of aliasing problem with low overhead as well as performance to a certain extent .

TO THE QUESTION OF RESPONSIBILITY FOR TORTURE IN THE RUSSIAN FEDERATION

2020 ◽  
Vol 10 (2) ◽  
pp. 103-106
Author(s):  
ASTEMIR ZHURTOV ◽  
Keyword(s):  
Human Rights ◽  
Russian Federation ◽  
Large Scale ◽  
Human Life ◽  
International Standards ◽  
World Community ◽  
The World ◽  
Long Time ◽  
Protection Of Human Rights ◽  
The Russian Federation

Cruel and inhumane acts that harm human life and health, as well as humiliate the dignity, are prohibited in most countries of the world, and Russia is no exception in this issue. The article presents an analysis of the institution of responsibility for torture in the Russian Federation. The author comes to the conclusion that the current criminal law of Russia superficially and fragmentally regulates liability for torture, in connection with which the author formulated the proposals to define such act as an independent crime. In the frame of modern globalization, the world community pays special attention to the protection of human rights, in connection with which large-scale international standards have been created a long time ago. The Universal Declaration of Human Rights and other international acts enshrine prohibitions of cruel and inhumane acts that harm human life and health, as well as degrade the dignity.Considering the historical experience of the past, these standards focus on the prohibition of any kind of torture, regardless of the purpose of their implementation.

RANCANG BANGUN PERANGKAT EKSPERIMENTASI PROSES PIROLISIS BIOMASA GELOMBANG MIKRO

2013 ◽  
Vol 14 (2) ◽  
Author(s):  
Noor Fachrizal
Keyword(s):  
Large Scale ◽  
Continuous Model ◽  
Biomass Energy ◽  
Scale Model ◽  
Small Scale ◽  
Laboratory Apparatus ◽  
Liquid Form ◽  
Large Scale Model ◽  
Bio Oil ◽  
Pyrolysis Of Biomass

Biomass such as agriculture waste and urban waste are enormous potency as energy resources instead of enviromental problem. organic waste can be converted into energy in the form of liquid fuel, solid, and syngas by using of pyrolysis technique. Pyrolysis process can yield higher liquid form when the process can be drifted into fast and flash response. It can be solved by using microwave heating method. This research is started from developing an experimentation laboratory apparatus of microwave-assisted pyrolysis of biomass energy conversion system, and conducting preliminary experiments for gaining the proof that this method can be established for driving the process properly and safely. Modifying commercial oven into laboratory apparatus has been done, it works safely, and initial experiments have been carried out, process yields bio-oil and charcoal shortly, several parameters are achieved. Some further experiments are still needed for more detail parameters. Theresults may be used to design small-scale continuous model of productionsystem, which then can be developed into large-scale model that applicable for comercial use.

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