Aneurysms as a Biomechanical Instability Problem

AbstractThe paper studies a higher order unfitted finite element method for the Stokes system posed on a surface in ℝ3. The method employs parametric Pk-Pk−1 finite element pairs on tetrahedral bulk mesh to discretize the Stokes system on embedded surface. Stability and optimal order convergence results are proved. The proofs include a complete quantification of geometric errors stemming from approximate parametric representation of the surface. Numerical experiments include formal convergence studies and an example of the Kelvin--Helmholtz instability problem on the unit sphere.

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Application of the dissipative particle dynamics method to the instability problem of a liquid thread

Physical Review E ◽

10.1103/physreve.94.063113 ◽

2016 ◽

Vol 94 (6) ◽

Cited By ~ 2

Author(s):

Chao-jie Mo ◽

Li-zi Qin ◽

Fei Zhao ◽

Li-jun Yang

Keyword(s):

Dissipative Particle Dynamics ◽

Particle Dynamics ◽

Instability Problem ◽

Dynamics Method

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Catastrophic Analysis of Seismic Response of Gravity Dam Sliding along Base Surface

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.311-313.2164 ◽

2011 ◽

Vol 311-313 ◽

pp. 2164-2168

Author(s):

Dun Ben Sun ◽

Qing Wen Ren

Keyword(s):

Weibull Model ◽

Gravity Dam ◽

Stable Region ◽

Instability Mechanism ◽

Gravity Dams ◽

Base Surface ◽

Instability Problem ◽

Nonlinear Constitutive Model ◽

Hysteresis Phenomena ◽

Sliding Instability

For the instability problem of gravity dam sliding along base surface, cubic nonlinear constitutive model of soft material in base surface is adopted, which is usually expressed by Weibull model. Dynamic Equations of dam sliding along base surface is established. By means of catastrophe theory, the jumping and hysteresis phenomena of the vibration amplitude of the dam is analyzed, the parameter range of stable region in which amplitude doesn’t happen catastrophe is given and the factors which cause amplitude instability are discussed. The results obtained in the paper are of significant value for understanding the sliding instability mechanism of gravity dam under earthquake, as well as guiding the design of gravity dams.

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Computational aspects of the gravitational instability problem for a multicomponent cosmological medium

Astrophysics and Space Science ◽

10.1007/bf00982331 ◽

1994 ◽

Vol 214 (1-2) ◽

pp. 139-149 ◽

Cited By ~ 1

Author(s):

H. J. Haubold ◽

A. M. Mathai

Keyword(s):

Gravitational Instability ◽

Instability Problem ◽

Computational Aspects

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Solutions to the instability problem of the DC input voltages of neutral point clamping multilevel inverter in photovoltaic chain connected to the network

2012 2nd International Symposium On Environment Friendly Energies And Applications ◽

10.1109/efea.2012.6294088 ◽

2012 ◽

Author(s):

Saliha Arezki ◽

Mohamed Boudour

Keyword(s):

Neutral Point ◽

Multilevel Inverter ◽

Instability Problem

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Finite Difference Approximation for the Barotropic Instability Problem

Journal of the Meteorological Society of Japan Ser II ◽

10.2151/jmsj1965.46.5_389 ◽

1968 ◽

Vol 46 (5) ◽

pp. 389-403 ◽

Cited By ~ 27

Author(s):

M. Yanai ◽

Tsuyoshi Nitta

Keyword(s):

Finite Difference ◽

Finite Difference Approximation ◽

Difference Approximation ◽

Barotropic Instability ◽

Instability Problem

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Local torque minimization for redundant manipulators: a correct formulation

Robotica ◽

10.1017/s0263574700019159 ◽

1996 ◽

Vol 14 (2) ◽

pp. 235-239 ◽

Cited By ~ 14

Author(s):

Shugen Ma ◽

Dragomir N. Nenchev

Keyword(s):

Redundant Manipulators ◽

Redundancy Resolution ◽

Instability Problem ◽

Correct Formulation ◽

Joint Velocity ◽

Recent Formulation ◽

Joint Acceleration ◽

Stable Scheme

SUMMARYLocal torque minimization for redundant manipulators has been considered by using a redundancy resolution approach. Since its initial formulation, however, proposed solutions have been plagued by performance instabilities. Till now, the reason was not clear. In this paper it is shown that the instability problem occurred because of incorrect formulation. A correct formulation is proposed, which is used to analyze the reason for instability. Special attention is paid to joint acceleration terms at the selfmotion manifold. This helps explaining the recent formulation of a stable scheme based on local joint velocity minimization in terms of torque. The results obtained. are related to dynamic redundancy resolution in general.

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Application of Catastrophe Theory in Surrounding Rock Stability

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.712-715.974 ◽

2013 ◽

Vol 712-715 ◽

pp. 974-978

Author(s):

Din Ge Kong ◽

Kai Hu

Keyword(s):

Catastrophe Theory ◽

Surrounding Rock ◽

Underground Engineering ◽

Rock System ◽

Instability Problem ◽

Rock Stability ◽

Highly Nonlinear ◽

Practical Engineering ◽

Simplified Mechanical Model ◽

Catastrophic Model

Surrounding rock system of underground engineering is highly nonlinear, and there is no unified cognition for its stability criteria. Introduces the basic principle of catastrophe theory, focusing on the cusp catastrophic model, build a simplified mechanical model for the surrounding rock, and the instability of surrounding rock of the cusp catastrophic model is obtained. In practical engineering, it is show that catastrophe theory is an effective method to study the instability problem of the tunnel.

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