Research on Chaotic Behavior of Concrete under External Load Based on Discontinuous Medium Mechanical Model

2009 ◽  
Vol 79-82 ◽  
pp. 1145-1148
Author(s):  
Hao Qin ◽  
Shu Cai Li
Keyword(s):  
External Load ◽  
Mechanical Model ◽  
Dynamical Equation ◽  
Chaotic Behavior ◽  
Concrete Material ◽  
Nonlinear Dynamical ◽  
Load Change ◽  
Nonlinear Science ◽  
Set Up ◽  
Discontinuous Medium

Outburst and random are typical characters of concrete when under external load. Traditional mechanics methods are difficult to be applied in. Depend on nonlinear science to set up the nonlinear dynamical equation that is fit for its characteristics. The subsystem dynamical equation of concrete is set up based on discontinuous medium mechanical model, and find that the concrete dynamical equation under external load is a Duffin equation. Then analyze and discuss the effect of external load on concrete by math analysis soft of maple. Results show that the concrete material take on complicated response to external load change.

Statics Analysis of the Mechanical Model of Nucleosome

2011 ◽  
Vol 343-344 ◽  
pp. 661-667 ◽  
Author(s):  
Yun Xue ◽  
De Wei Weng ◽  
Gang Ming Gong
Keyword(s):  
Mechanical Model ◽  
The Other ◽  
Elastic Rod ◽  
Equilibrium Equations ◽  
Constraint Force ◽  
Precession Angle ◽  
Nutation Angle ◽  
Analytic Expression ◽  
Set Up ◽  
Calculated Analysis

Mechanical model of nucleoside and its equilibrium equations are set up, and the mechanical properties on the equilibrium position are analyzed. In the case constraint force and electrostatic attraction between cylinder OH and elastic rod are balanced, the analytic expression of nutation angle of the section and its conditions of existence are given. It is show that the cylinder OH can maintain equilibrium at any range of the precession angle. In the other case when unbanced, there is phenomenon of separation of elastic rod from cylinder OH in the spiral wound 2 circles, and numerical solution of the precession angle at separation points are calculated. Analysis of equilibrium of cylinder H1 illustrates that the generatrix of cylinder H1 and OH are not parallel, and the angle between them is obtained

scholarly journals Nonlinear Dynamical Equation for Irreversible, Steepest-Entropy-Ascent Relaxation to Stable Equilibrium

2007 ◽  
Author(s):  
Gian Paolo Beretta ◽  
Guillaume Adenier ◽  
Andrei Yu. Khrennikov ◽  
Pekka Lahti ◽  
Vladimir I. Man'ko ◽  
...  
Keyword(s):  
Dynamical Equation ◽  
Stable Equilibrium ◽  
Nonlinear Dynamical

Evaluation of Damaging Effects on a NPP Integrity Subjected to Beyond Design Earthquake

2013 ◽  
Author(s):  
Rosa Lo Frano ◽  
Giuseppe Forasassi
Keyword(s):  
Stress Tests ◽  
Material Behaviour ◽  
Concrete Material ◽  
Ground Shaking ◽  
Seismic Loadings ◽  
Reactor Materials ◽  
Design Characteristics ◽  
Nuclear Structures ◽  
Set Up ◽  
Design Earthquake

The aim of this study is to evaluate the influence of the damaging or failure effects induced by seismic loadings on the loading bearing capability of the overall nuclear structures, systems and components (SSCs). In particular it was analyzed the behaviour of the SSCs in terms of their required safety functions and capacity assuming the occurrence of an earthquake having magnitude beyond the design basis value (in agreement with the “stress tests” suggestions, presently foreseen by the European and International Associations). To the purpose, quite refined FEM models were set up and implemented considering suitable materials behaviour and constitutive laws for the reactor materials, particularly for the concrete material behaviour (which could suffer failure and damage mechanisms during the ground shaking). Several type of damaging mechanics were considered. The obtained results seemed to confirm the overall containment reliability even if with minor upgrading actions in operating procedures and design characteristics. Moreover they allowed to appropriately check the NPP containment strength reserve.

Numerical Model of Melt-Through in a Fully Penetrated GTA Weld Pool

2011 ◽  
Vol 221 ◽  
pp. 622-628
Author(s):  
Peng Cheng Zhao ◽  
Shu Jiang Li
Keyword(s):  
Liquid Metal ◽  
Weld Pool ◽  
Arc Welding ◽  
Mechanical Model ◽  
Bottom Surface ◽  
Welding Parameters ◽  
Quasi Steady State ◽  
Gas Tungsten Arc ◽  
Factors Influencing ◽  
Set Up

A mechanical model of the fully penetrated gas tungsten arc welding (GTAW) weld pool was established to investigate how the melt-through takes place. Analyses show that the forces acting on the liquid metal column which locates in the center of weld pool, whose undersurface and altitude are the bottom surface and thickness of weld pool respectively, determine whether the melt-through occurs. A criterion is set up for judging whether the workpiece will melt through with a specific thickness and selected welding parameters. Factors influencing the melt-through are studied theoretically, and the magnitude and scale of forces that acting on the liquid metal column in a quasi-steady state weld pool are calculated numerically. By using the established criterion, welding currents suitable for a workpiece with specific thickness are predicted.

Numerical simulation of wrinkle morphology formation and the evolution of different Bacillus subtilis biofilms

2015 ◽  
Vol 73 (3) ◽  
pp. 527-534 ◽  
Author(s):  
Xiaoling Wang ◽  
Mudong Hao ◽  
Guoqing Wang
Keyword(s):  
Mechanical Properties ◽  
Bacillus Subtilis ◽  
Mechanical Model ◽  
Quantitative Relationship ◽  
Finite Element Software ◽  
Model And Simulation ◽  
Agar Substrate ◽  
Set Up ◽  
And Control ◽  
Number Of Bacteria

Wrinkle morphology is a distinctive phenomenon observed in mature biofilms that are produced by a great number of bacteria. The wrinkle pattern depends on the mechanical properties of the agar substrate and the biofilm itself, governed by the extracellular matrix (ECM). Here we study the macroscopic structures and the evolution of Bacillus subtilis biofilm wrinkles using the commercial finite element software ABAQUS. A mechanical model and simulation are set up to analyze and evaluate bacteria biofilm's wrinkle characteristics. We uncover the wrinkle formation mechanism and enumerate the quantitative relationship between wrinkle structure and mechanical properties of biofilm and its substrate. Our work can be used to modify the wrinkle pattern and control the biofilm size.

Design of Shield Hydraulic Support with Variable Parameters

2011 ◽  
Vol 121-126 ◽  
pp. 1411-1415 ◽  
Author(s):  
Xi Jing Zhao ◽  
Jun Min Lu ◽  
Rui Luo
Keyword(s):  
Research And Development ◽  
Mechanical Model ◽  
Mechanical Modeling ◽  
Hydraulic Support ◽  
Development Environment ◽  
Support Design ◽  
Variable Parameters ◽  
Development Platform ◽  
Software Development Environment ◽  
Set Up

This paper builds the design platform for the shield hydraulic support with variable parameters.The platform characterizes the following aspects: support’s mechanical modeling, the whole and parts designing,strength checking. With the aid of VC++ software development environment, the mechanical model with variable parameters is set up and the support design is carried on,including design and check of the whole support and its components,such as top beam,shielding beam,the baseboard and so on. The development of this software could shorten the research and development periods of supports with similar structures and provide the research and development platform for the support design.

scholarly journals COVARIANT FEATURE OF THE MIXMASTER MODEL INVARIANT MEASURE

2002 ◽  
Vol 11 (08) ◽  
pp. 1321-1330 ◽  
Author(s):  
GIOVANNI IMPONENTE ◽  
GIOVANNI MONTANI
Keyword(s):  
Invariant Measure ◽  
Arbitrary Function ◽  
Chaotic Behavior ◽  
Time Variable ◽  
Cosmological Singularity ◽  
Constant Of Motion ◽  
Set Up ◽  
Lapse Function ◽  
Mixmaster Model ◽  
Hamiltonian Analysis

We provide a Hamiltonian analysis of the Mixmaster Universe dynamics showing the covariant nature of its chaotic behavior with respect to any choice of time variable. Asymptotically to the cosmological singularity, we construct the appropriate invariant measure for the system (which relies on the appearance of an "energy-like" constant of motion) in such a way that its existence is independent of fixing the time gauge, i.e. the corresponding lapse function. The key point in our analysis consists of introducing generic Misner–Chitré-like variables containing an arbitrary function, whose specification allows us to set up the same statistical scheme in any time gauge.

Numerical Phenomena of a Spatial Mechanism With Clearances

1994 ◽  
Author(s):  
Zhang Jianling ◽  
Li Zhe ◽  
Bai Shixian
Keyword(s):  
Differential Equation ◽  
Mechanical Model ◽  
Equation Of Motion ◽  
Numerical Results ◽  
Dynamic Responses ◽  
Spatial Mechanism ◽  
Spatial Mechanisms ◽  
Steady State Responses ◽  
Set Up ◽  
State Responses

Abstract The general mechanical model of C pair with clearances is set up and used to derive the differential equation of motion of a RSCR mechanism with clearance at C pair in this paper. The numerical results are analysed and compared with the dynamic responses of the nominal RSCR mechanism. Chaotic phenomena can be seen in the numerical results, which indicate that the steady state responses may not be achievable for spatial mechanisms with clearance connections.

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