Estimation of the elastic stiffness coefficient c13 of fixed tendon and fixed myocardium

1995 ◽  
Vol 97 (5) ◽  
pp. 3171-3176 ◽  
Author(s):  
Brent K. Hoffmeister ◽  
Scott M. Handley ◽  
Edward D. Verdonk ◽  
Samuel A. Wickline ◽  
James G. Miller
Keyword(s):  
Elastic Stiffness ◽  
Stiffness Coefficient

Analysis of Micro Structure’s Elastic Stiffness

2012 ◽  
Vol 184-185 ◽  
pp. 890-895
Author(s):  
Li Shen ◽  
Shi Qiao Gao ◽  
An Ran Jiang ◽  
Cai Feng Wang
Keyword(s):  
Linear Relationship ◽  
Elastic Stiffness ◽  
Small Displacement ◽  
Stiffness Coefficient ◽  
Polynomial Fitting ◽  
Non Linear ◽  
Simulation Results ◽  
The Relationship

Based on the calculation and analysis of three kinds of elastic beam’s stiffness coefficient in micro machined gyroscope, the results show: in the condition of small displacement，forces and displacement are linear relationship in clamped-clamped beam, crab-foot beam and bow beam; but as the displacement increases, the relationship between forces and displacement are obvious non-linear in clamped-clamped beam. When the displacement is three times the length of beam’s width, the bow beam’s force and displacement are linear relationship. By ANSYS crab-foot beam and bow beam’s stiffness is obtained, the simulation results and the polynomial fitting coefficient are all credible.

Numerical and Experimental Research on the Fluid-Induced Forces of Clearance Flow in Canned Motor Reactor Coolant Pump

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Rui Xu ◽  
Yun Long ◽  
Yaoyu Hu ◽  
Junlian Yin ◽  
Dezhong Wang
Keyword(s):  
Large Mass ◽  
Stiffness Coefficient ◽  
Pressurized Water ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Various Boundary Conditions ◽  
Clearance Flow ◽  
Mass Coefficient ◽  
Cfd Method ◽  
Canned Motor

Reactor coolant pump (RCP) is one of the most important equipment of the coolant loop in a pressurized water reactor system. Its safety relies on the characteristics of the rotordynamic system. For a canned motor RCP, the liquid coolant fills up the clearance between the metal shields of the rotor and stator inside the canned motor, forming a long clearance flow. The fluid-induced forces of the clearance flow in canned motor RCP and their effects on the rotordynamic characteristics of the pump are numerically and experimentally analyzed in this work. A transient computational fluid dynamics (CFD) method has been used to investigate the fluid-induced force of the clearance. A vertical experiment rig has also been established for the purpose of measuring the fluid-induced forces. Fluid-induced forces of clearance flow with various whirl frequencies and various boundary conditions are obtained through the CFD method and the experiment. Results show that clearance flow brings large mass coefficient into the rotordynamic system and the direct stiffness coefficient is negative under the normal operating condition. The rotordynamic stability of canned motor RCP does not deteriorate despite the existence of significant cross-coupled stiffness coefficient from the fluid-induced forces of the clearance flow.

scholarly journals Sensitivity Based Selection of an Optimal Cable-Driven Parallel Robot Design for Rehabilitation Purposes

Robotics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 7
Author(s):  
Ferdaws Ennaiem ◽  
Abdelbadiâ Chaker ◽  
Juan Sebastián Sandoval Arévalo ◽  
Med Amine Laribi ◽  
Sami Bennour ◽  
...  
Keyword(s):  
Pareto Front ◽  
Parallel Robot ◽  
Elastic Stiffness ◽  
Upper Limb Rehabilitation ◽  
Daily Life Activities ◽  
System A ◽  
The Monte Carlo Method ◽  
Genetic Algorithm Method ◽  
Limb Rehabilitation ◽  
Selection Of

This paper deals with the design of an optimal cable-driven parallel robot (CDPR) for upper limb rehabilitation. The robot’s prescribed workspace is identified with the help of an occupational therapist based on three selected daily life activities, which are tracked using a Qualisys motion capture system. A preliminary architecture of the robot is proposed based on the analysis of the tracked trajectories of all the activities. A multi-objective optimization process using the genetic algorithm method is then performed, where the cable tensions and the robot size are selected as the objective functions to be minimized. The cables tensions are bounded between two limits, where the lower limit ensures a positive tension in the cables at all times and the upper limit represents the maximum torque of the motor. A sensitivity analysis is then performed using the Monte Carlo method to yield the optimal design selected out of the non-dominated solutions, forming the obtained Pareto front. The robot with the highest robustness toward the disturbances is identified, and its dexterity and elastic stiffness are calculated to investigate its performance.

scholarly journals The influence of stiffness coefficient of steel support on supporting effect and its optimization

2021 ◽  
Vol 714 (3) ◽  
pp. 032044
Author(s):  
Jie Zhang ◽  
Yue Li ◽  
Xinyue Zhao ◽  
Shenyue Shi ◽  
Wenxia Liu ◽  
...  
Keyword(s):  
Stiffness Coefficient ◽  
Supporting Effect

scholarly journals Finite element modeling of multiple density materials of bone specimens for biomechanical behavior evaluation

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sebastián Irarrázaval ◽  
Jorge Andrés Ramos-Grez ◽  
Luis Ignacio Pérez ◽  
Pablo Besa ◽  
Angélica Ibáñez
Keyword(s):  
Finite Elements ◽  
Computational Models ◽  
Reaction Force ◽  
Elastic Stiffness ◽  
Finite Elements Method ◽  
Mechanical Resistance ◽  
Assessment Procedure ◽  
Axial Tomography ◽  
Biomechanical Behavior ◽  
Ct Data

AbstractThe finite elements method allied with the computerized axial tomography (CT) is a mathematical modeling technique that allows constructing computational models for bone specimens from CT data. The objective of this work was to compare the experimental biomechanical behavior by three-point bending tests of porcine femur specimens with different types of computational models generated through the finite elements’ method and a multiple density materials assignation scheme. Using five femur specimens, 25 scenarios were created with differing quantities of materials. This latter was applied to computational models and in bone specimens subjected to failure. Among the three main highlights found, first, the results evidenced high precision in predicting experimental reaction force versus displacement in the models with larger number of assigned materials, with maximal results being an R2 of 0.99 and a minimum root-mean-square error of 3.29%. Secondly, measured and computed elastic stiffness values follow same trend with regard to specimen mass, and the latter underestimates stiffness values a 6% in average. Third and final highlight, this model can precisely and non-invasively assess bone tissue mechanical resistance based on subject-specific CT data, particularly if specimen deformation values at fracture are considered as part of the assessment procedure.

scholarly journals Research and Implementation of an Automatic Reset Force of a Force Feedback Handle

2020 ◽  
Vol 316 ◽  
pp. 01003
Author(s):  
Xin An Qiu ◽  
Shi Jia Wang ◽  
Dong Tao Ma
Keyword(s):  
Force Feedback ◽  
High Accuracy ◽  
Damping Coefficient ◽  
Robotic Arm ◽  
Force Model ◽  
Stiffness Coefficient ◽  
Application Field ◽  
New Development

Take the force feedback handle applied to the teleoperation of space robotic arm as a requirement. In order to improve users’ experience, we studied the automatic reset force of the handle. This paper proposes a springdamping model and applies it to the torque output of the motor to achieve a good reset of the handle, which is a new development of the application field of the automatic reset force model of the force feedback device. The experiment shows that the automatic reset force model has high accuracy when the handle returns to zero. In addition, through dynamic and reasonable adjustment of the stiffness coefficient and damping coefficient, it can meet the needs of different users for the automatic reset force of the force feedback handle.

scholarly journals Determination of the Elastic Tensor of a Textured Low-Carbon Steel

1993 ◽  
Vol 21 (1) ◽  
pp. 3-16 ◽  
Author(s):  
P. Spalthoff ◽  
W. Wunnike ◽  
C. Nauer-Gerhard ◽  
H. J. Bunge ◽  
E. Schneider
Keyword(s):  
Carbon Steel ◽  
Elastic Anisotropy ◽  
Low Carbon Steel ◽  
Elastic Stiffness ◽  
Ultrasonic Pulse ◽  
Grain Structure ◽  
Maximum Deviation ◽  
Low Carbon ◽  
The Hill ◽  
Pulse Echo

The components of the elastic stiffness tensor of hot rolled low-carbon steel were determined using an ultrasonic pulse-echo-method. They were also calculated on the basis of X-ray texture measurements using the Hill approximation. The maximum deviation between experimental and calculated values is 3.5%. An influence of the slightly anisotropic grain structure on the elastic anisotropy could not be seen.

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