scholarly journals Elastic stiffness of metallic multilayers studied by picosecond ultrasonics: improved interpretation of interface elasticity

2019 ◽  
Vol 58 (7) ◽  
pp. 075504
Author(s):  
Nobutomo Nakamura ◽  
Ryo Yokomura ◽  
Nobutaka Takeuchi ◽  
Daiki Yamakado ◽  
Hirotsugu Ogi
2011 ◽  
Vol 98 (10) ◽  
pp. 101911 ◽  
Author(s):  
N. Nakamura ◽  
A. Uranishi ◽  
M. Wakita ◽  
H. Ogi ◽  
M. Hirao ◽  
...  

2011 ◽  
Vol 110 (7) ◽  
pp. 073505 ◽  
Author(s):  
Yu-Chieh Wen ◽  
Yang-Chung Liao ◽  
Hsian-Hong Chang ◽  
Boon-How Mok ◽  
Yung-Chi Lee ◽  
...  

1996 ◽  
Vol 219-220 ◽  
pp. 681-683 ◽  
Author(s):  
B. Perrin ◽  
B. Bonello ◽  
J.-C. Jeannet ◽  
E. Romatet

2002 ◽  
Vol 727 ◽  
Author(s):  
A. M. Mazzone

AbstractFull Potential Linearized Augmented Plane Wave calculations have been performed for epitaxial multilayers formed by the noble metals Ag and Cu with a thickness n up to 10 layers. The multilayers have a fcc lattice and are pure or compositionally modulated with a structure of the type Agn Cun or (AgCu)n. For n in the range 2,3 the density of states, evaluated at paramagnetic level, exhibits a sharp reduction of the bandwidth which is consistent with the reduced coordination of these structures. For n ≤ 5 the density of states in the central layers converges to the bulk value while the outer layers retain the narrow bandwidth found at n=2. Due to the absence of charge intermixing and hybridization, these features are shared by multilayers of all composition.


Robotics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 7
Author(s):  
Ferdaws Ennaiem ◽  
Abdelbadiâ Chaker ◽  
Juan Sebastián Sandoval Arévalo ◽  
Med Amine Laribi ◽  
Sami Bennour ◽  
...  

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.


2020 ◽  
Vol 128 (16) ◽  
pp. 160902 ◽  
Author(s):  
Fernando Pérez-Cota ◽  
Rafael Fuentes-Domínguez ◽  
Salvatore La Cavera ◽  
William Hardiman ◽  
Mengting Yao ◽  
...  

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sebastián Irarrázaval ◽  
Jorge Andrés Ramos-Grez ◽  
Luis Ignacio Pérez ◽  
Pablo Besa ◽  
Angélica Ibáñez

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.


SIMULATION ◽  
2021 ◽  
pp. 003754972199645
Author(s):  
Philippe Babilotte

Complete numerical simulations are given under SciLab® and MATLAB® coding environments, concerning propagative acoustic wavefronts, for laser picosecond ultrasonics under multiwavelength conditions. Simulations of the deformation field and its propagation into bulk material are given under different wavelength configurations for optical pump and probe beams, which are used to generate and to detect the acoustic signal. Complete insights concerning the dynamics of the acoustic waves are given, considering the absence of carrier diffusions into the material. Several numerical approaches are proposed concerning both the functions introduced to simulate the wavefront ( Heaviside or error) and the coding approach (linear/vectorized/ Oriented Object Programming), under the pure thermo-elastic approach.


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