Active Control of Elastic and Rigid Body Response of a Three Dimensional Underwater Structure

1995 ◽  
Vol 117 (1) ◽  
pp. 30-37 ◽  
Author(s):  
H. Suzuki ◽  
K. Yoshida ◽  
K. Watanabe
Keyword(s):  
Numerical Model ◽  
Rigid Body ◽  
Active Control ◽  
Structural Model ◽  
Scale Up ◽  
Three Dimensional ◽  
Basic Research ◽  
Weather Conditions ◽  
Body Motion ◽  
Elastic Response

One key technology for the offshore development of the increasing water depth will be remotely operated installation and construction of flexible structure in the deep water or on the seabed. The flexibility comes from scale-up or weight reduction of the structure. Conventional operation from the sea surface is affected by the weather conditions, and, therefore, not so efficient. This paper presents basic research on active control of elastic response and rigid body motion of an underwater elastic structure toward the remotely operated installation technique. The numerical model of the dynamics of the structural model is formulated, and based on the numerical model the control is formulated. The formulated control is tested by computer simulations and model experiments. The structural model is propelled by thrusters and taken from initial position to another position, while the elastic responses are controlled by variable buoyancy-type actuators.

Test of Solidification Characteristics of Grouting and the Effect on Strata Deformation in Shield Tunnelling

2012 ◽  
Vol 568 ◽  
pp. 80-84
Author(s):  
Xiao Chun Zhong ◽  
Wei Ke Qin ◽  
Hai Wang
Keyword(s):  
Numerical Model ◽  
Rigid Body ◽  
Active Control ◽  
Calculation Method ◽  
Civil Engineering ◽  
Test Results ◽  
Shield Tunneling ◽  
Shield Tunnelling ◽  
Strata Deformation ◽  
Over Time

Back-fill Grouting is a key procedure for the active control of strata settlement during shield tunnelling in civil engineering. The paper studies the stress - strain characteristics of grouting and the state of grout, which changes from liquid to solid over time and is simulated by variable rigid body. The model of flowing state are divided in four phases from liquid-plastic to rigid state. The paper establish a numerical model of shield tunnelling in civil engineering with the consideration of characteristics of grout deformation, and has analyzed law of strata settlement. The test results show that the calculation method can well accord with the four stages of strata deformation, and can more accurately reflect the process of strata deformation caused by shield tunneling.

Segmental motion and deformation of transmurally infarcted myocardium in acute postinfarct period

1995 ◽  
Vol 268 (3) ◽  
pp. H1304-H1312 ◽  
Author(s):  
J. A. Lima ◽  
V. A. Ferrari ◽  
N. Reichek ◽  
C. M. Kramer ◽  
L. Palmon ◽  
...  
Keyword(s):  
Rigid Body ◽  
Coronary Occlusion ◽  
Three Dimensional ◽  
Magnetic Resonance Images ◽  
Body Motion ◽  
Segmental Motion ◽  
Infarcted Myocardium ◽  
Tissue Tagging ◽  
Coronary Ligation ◽  
Principal Strains

Mechanical behavior of infarcted myocardium in the first week following coronary occlusion has not been well characterized. Prior unidimensional studies failed to account for perpendicular deformation or shearing. This study characterizes three-dimensional motion and deformation of transmural infarcts 1 wk after coronary ligation in seven sheep. Principal strains and systolic in-plane translation and rotation were calculated for triangular elements defined by tissue tagging in short- and long-axis magnetic resonance images. The magnitudes of the first and second principal strains were reduced in both the short- and long-axis planes 1 wk after infarction. In addition, the absolute angular difference between the direction of the first principal strain and the radial direction increased from 14.7 +/- 1.9 to 43.5 +/- 2.7 degrees in the short-axis plane and from 19.6 +/- 7.3 to 43.9 +/- 10.0 degrees (P < 0.05) in the long-axis plane. In-plane rigid-body translation and rotation were also reduced in both planes. In conclusion, marked reduction and reorientation of principal strains and reduction in segmental rigid-body motion characterize nonreperfused transmural myocardial infarctions 1 wk after coronary occlusion.

Numerical Sloshing Analysis of FLNG and LNGC Considering Two-Body Motion Effect

2011 ◽  
Author(s):  
Jong Jin Park ◽  
Hiroshi Kawabe ◽  
Mun Sung Kim ◽  
Byung Woo Kim ◽  
Jae Kwang Eom
Keyword(s):  
Numerical Model ◽  
Frequency Domain ◽  
Potential Theory ◽  
Three Dimensional ◽  
Coupled Model ◽  
Ship Motion ◽  
Body Motion ◽  
Liquid Motion ◽  
Motion Effect

Side by Side arrangement is considered for the LNG-FPSO offloading operations. In that case, two-body coupled effects are important for LNG-FPSO and LNGC motion and sloshing analysis. The present study is concerned with a ship motion and sloshing analysis considering two-body motion and sloshing-motion coupled effects. The methodology is based on three-dimensional potential theory on a coupled model of LNG-FPSO and LNGC in the frequency domain. To calculation sloshing impact pressures, the violent liquid motion inside tank is treated with three-dimensional numerical model adopting SOLA-VOF scheme.

Optimizing spherical navigator echoes for three-dimensional rigid-body motion detection

2005 ◽  
Vol 53 (5) ◽  
pp. 1080-1087 ◽  
Author(s):  
Daniel W. Petrie ◽  
Andreu F. Costa ◽  
Atsushi Takahashi ◽  
Yi-Fen Yen ◽  
Maria Drangova
Keyword(s):  
Rigid Body ◽  
Motion Detection ◽  
Three Dimensional ◽  
Rigid Body Motion ◽  
Body Motion

Dynamic Analysis of Flexible Supercavitating Vehicles Using Modal Based Elements

2003 ◽  
Author(s):  
Jou-Young Choi ◽  
Massimo Ruzzene ◽  
Olivier A. Bauchau
Keyword(s):  
Numerical Model ◽  
Rigid Body ◽  
Degrees Of Freedom ◽  
Structural Characteristics ◽  
Rigid Body Motion ◽  
Operating Conditions ◽  
Flight Mechanics ◽  
Body Motion ◽  
Supercavitating Vehicles ◽  
Elastic Modes

This presents a numerical model for the simulation of the flight mechanics behavior of flexible supercavitating vehicles. Supercavitating vehicles exploit supercavitation as a means to reduce drag and increase the underwater speed. In the proposed formulation, the vehicle’s rigid body motion is described by 6 degrees of freedom, which define pitch, yaw and roll motion and the displacement of the center of gravity with respect to a fixed inertial reference system. The forces applied to the vehicle include the control actions at the nose and at the fins, propulsion, gravity and cavity/vehicle periodic interactions associated to typical operating conditions. The elastic displacements are superimposed to the rigid body motion through a modal superposition technique. The mode synthesis is performed using Herting’s Transformation, which provides maximum flexibility in the selection of the elastic modes to be used for the used for the superposition, and the possibility of easily handling free-free modes. The developed numerical model predicts the dynamic response of the considered class of supercavitating vehicles resulting from assigned maneuvers. The analysis is motivated by the need of accurately modeling the structural characteristics of supercavitating vehicles in order to estimate vibrations in the structure and to envision and design systems that improve their guidance and control efficiency.

scholarly journals Three-dimensional phase field sintering simulations accounting for the rigid-body motion of individual grains

2021 ◽  
Vol 186 ◽  
pp. 109963
Author(s):  
Robert Termuhlen ◽  
Xanthippi Chatzistavrou ◽  
Jason D. Nicholas ◽  
Hui-Chia Yu
Keyword(s):  
Rigid Body ◽  
Phase Field ◽  
Three Dimensional ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Individual Grains

scholarly journals Estimation of the Rigid-Body Motion From Three-Dimensional Images Using a Generalized Center-of-Mass Points Approach

2006 ◽  
Vol 53 (5) ◽  
pp. 2712-2718 ◽  
Author(s):  
B. Feng ◽  
P.P. Bruyant ◽  
P.H. Pretorius ◽  
R.D. Beach ◽  
H.C. Gifford ◽  
...  
Keyword(s):  
Rigid Body ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Three Dimensional Images ◽  
Generalized Center
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