scholarly journals Potential of Workshop Measurement Positioning System to Measure Oscillation Frequencies of Rigid Structures

2019 ◽  
Vol 9 (3) ◽  
pp. 595 ◽  
Author(s):  
Chunbao Xiong ◽  
Hongzhi Bai ◽  
Jiarui Lin
Keyword(s):  
Three Dimensional ◽  
Transformation Method ◽  
Fast Fourier Transformation ◽  
Positioning System ◽  
Test Bed ◽  
Coordinate Measurement ◽  
Intrinsic Parameters ◽  
High Measurement ◽  
Fourier Transformation Method ◽  
Oscillation Frequencies

A workshop measuring and positioning system (wMPS) is a large three-dimensional (3D) coordinate-measurement system based on optoelectronic scanning. It is capable of large-range coverage, high measurement accuracy and frequency, and multi-task synchronous measurement. Existing geodetic instruments cannot measure the intrinsic parameters of strong rigid structures. Thus, this study conducted experiments to explore the feasibility of the wMPS to measure the intrinsic parameters of rigid structures. A test bed was established using a reverse-engineering method to simulate the oscillation frequency of the structure. Displacement data, which changed with the time series through the fast Fourier transformation method, were analyzed to determine the feasibility and range of the wMPS in measuring intrinsic parameters of the structure. The experimental results demonstrated that the wMPS can measure the vibrational frequency up to 9 Hz with a 3-mm amplitude and up to 4 Hz with a 30-mm amplitude.

Acoustic waves in two-fraction mixtures of liquid with vapor-gas bubbles

2012 ◽  
Vol 9 (1) ◽  
pp. 65-68
Author(s):  
R.N. Gafiyatov
Keyword(s):  
Acoustic Waves ◽  
Gas Bubbles ◽  
Transformation Method ◽  
Fast Fourier Transformation ◽  
Fourier Transformation Method ◽  
Impulse Pressure ◽  
Pressure Perturbations ◽  
The Mathematical Model ◽  
Different Gases ◽  
Fractional Mixture

The mathematical model of two-fractional mixture of liquid with vapor-gas bubbles of different gases and sizes with phase transformations is presented. The dispersive equation is received, dispersive curves that determine the propagation of acoustic disturbances was plotted. Calculations on the propagation of impulse pressure perturbations were performed by means of a fast Fourier transformation method.

scholarly journals Fast Fourier Transformation method for computing the permeability of periodic porous media

2017 ◽  
Vol 39 (2) ◽  
pp. 121-133
Author(s):  
Nguyen Trung Kien ◽  
Nguyen Duy Hung
Keyword(s):  
Porous Media ◽  
Fourier Transformation ◽  
Linear Problem ◽  
Stokes Equations ◽  
Solid Phase ◽  
Transformation Method ◽  
Fast Fourier Transformation ◽  
Fourier Space ◽  
Fourier Transformation Method ◽  
Rigid Skeleton

A Fourier-based method is adopted to determine the permeability of periodic porous media made up of a rigid skeleton saturated by viscous fluid. The flow, induced by a prescribed macroscopic gradient of pressure, adopts the Stokes equations with incorporating a condition of adherence at the surface of the solid. The permeability is determined by solving a linear problem on a unit cell for which we determine the local velocity fields due to a prescribed gradient of pressure. The method uses the Fourier Transformation and exact expressions of the periodic Green tensor in the Fourier space. It is shown that the resolution of the problem requires an introducing of undetermined forces acting within the solid phase.

scholarly journals FFT simulations and multi-coated inclusion model for macroscopic conductivity of 2D suspensions of compound inclusions

2015 ◽  
Vol 37 (3) ◽  
pp. 169-176
Author(s):  
Nguyen Van Luat ◽  
Nguyen Trung Kien
Keyword(s):  
Approximation Method ◽  
Fourier Transformation ◽  
Dimensional Space ◽  
Transformation Method ◽  
Fast Fourier Transformation ◽  
Two Dimensional ◽  
Random Models ◽  
Coated Inclusion ◽  
Fourier Transformation Method ◽  
Fast Fourier Transformation Method

Article introduces the Fast-Fourier transformation method (FFT) and an approximation method to calculate the conductivity of compound-inclusion composites in two-dimensional space. The approximation compares favorably with the numerical results for a number of periodic and random models over a range of volume proportions of phases, but divers at large volume proportions of the included phases when the interactions between the inclusions are more pronounced.

scholarly journals Fourier Transformation method for solving integral equation in the 2.5D problem of electric sounding

2021 ◽  
Vol 2092 (1) ◽  
pp. 012018
Author(s):  
D.S. Rakisheva ◽  
B.G. Mukanova
Keyword(s):  
Integral Equation ◽  
Performance Improvement ◽  
Fourier Transformation ◽  
Surface Relief ◽  
Three Dimensional ◽  
Transformation Method ◽  
Parallel Version ◽  
Significant Performance ◽  
Fourier Transformation Method ◽  
The Fourier Transform

Abstract The paper discusses a method for solving an integral equation for calculating a three-dimensional electric field in a medium with a two-dimensional geometry based on the Fourier transform. The results of the numerical solution of the transformed integral equation and the original integral equation for the medium with the surface relief are compared. The original equation was solved using parallelization technologies on a system with shared memory. A significant performance improvement based on the transformed equations, including in comparison with the parallel version of the program for the original integral equation, is shown.

scholarly journals A Toeplitz Jacobian Matrix/Fast Fourier Transformation Method for Steady-State Analysis of Discontinuous Oscillators

1995 ◽  
Vol 2 (3) ◽  
pp. 205-218 ◽  
Author(s):  
T. Ge ◽  
A. Y. T. Leung
Keyword(s):  
Harmonic Balance ◽  
Fourier Transformation ◽  
Harmonic Balance Method ◽  
Numerical Differentiation ◽  
Transformation Method ◽  
Fast Fourier Transformation ◽  
Arc Length ◽  
Nonlinear Characteristics ◽  
Fourier Transformation Method ◽  
Branch Switching

A semianalytical algorithm is proposed for the solutions and their stability of a piecewise nonlinear system. The conventional harmonic balance method is modified by the introduction of Toeplitz Jacobian matrices (TJM) and by the alternative applications of fast Fourier transformation (FFT) and its inverse. The TJM/FFT method substantially reduces the amount of computation and circumvents the necessary numerical differentiation for the Jacobian. An arc-length algorithm and a branch switching procedure are incorporated so that the secondary branches can be independently traced. Oscillators with piecewise nonlinear characteristics are taken as illustrative examples. Flip, fold, and Hopf bifurcations are of interest.

An innovative prone positioning system for advanced deformity and frailty in complex spine surgery

2020 ◽  
Vol 32 (2) ◽  
pp. 229-234
Author(s):  
Benjamin Kolb ◽  
John Large ◽  
Stuart Watson ◽  
Glyn Smurthwaite
Keyword(s):  
Ankylosing Spondylitis ◽  
Three Dimensional ◽  
Technical Note ◽  
Positioning System ◽  
Prone Positioning ◽  
Economic Implications ◽  
Potential Safety ◽  
Chest Deformity ◽  
Positioning Device ◽  
Skin Quality

The authors present a technical note for a prone positioning system developed to facilitate cervical extension osteotomy for ankylosing spondylitis in the presence of severe deformity and frailty. Chin-on-chest deformity represents one of the most debilitating changes of ankylosing spondylitis. Where the chin-brow angle approaches or exceeds 90°, prone positioning becomes problematic due to the fixed position of the head. Furthermore, the challenge is compounded where physiological deconditioning leads to frailty, and the side effects of medical therapies decrease muscle mass and skin quality. Conventional prone positioning equipment is not able to cater to all patients. A versatile system was developed using a 3D reconstruction to enable a positioning simulation and verification tool. The tool was used to comprehensively plan the perioperative episode, including spatial orientation and associated equipment. Three-dimensional printing was used to manufacture a bespoke positioning device that precisely matched the contours of the patient, reducing contact pressure and risk of skin injury. The authors were able to safely facilitate surgery for a patient whose deformity and frailty may otherwise have precluded this possibility. The system has potential safety and economic implications that may be of significant utility to other institutions engaging in complex spinal surgery.

Research on the Reliability of Box for Gear Test Bed

2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan
Keyword(s):  
Power Flow ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Test Bed ◽  
Kinematics Simulation ◽  
Beveloid Gears ◽  
Overall Performance

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.

Evaluating the Effect of Three-Dimensional Visualization on Force Application and Performance Time during Robotics-Assisted Mitral Valve Repair

2013 ◽  
Vol 8 (3) ◽  
pp. 199-205 ◽  
Author(s):  
Maria E. Currie ◽  
Ana Luisa Trejos ◽  
Reiza Rayman ◽  
Michael W.A. Chu ◽  
Rajni Patel ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Mitral Valve ◽  
Haptic Feedback ◽  
3D Visualization ◽  
Three Dimensional ◽  
Test Bed ◽  
Mitral Valve Annuloplasty ◽  
Significant Difference ◽  
The Mean ◽  
Mean Time

Objective The purpose of this study was to determine the effect of three-dimensional (3D) binocular, stereoscopic, and two-dimensional (2D) monocular visualization on robotics-assisted mitral valve annuloplasty versus conventional techniques in an ex vivo animal model. In addition, we sought to determine whether these effects were consistent between novices and experts in robotics-assisted cardiac surgery. Methods A cardiac surgery test-bed was constructed to measure forces applied during mitral valve annuloplasty. Sutures were passed through the porcine mitral valve annulus by the participants with different levels of experience in robotics-assisted surgery and tied in place using both robotics-assisted and conventional surgery techniques. Results The mean time for both the experts and the novices using 3D visualization was significantly less than that required using 2D vision (P < 0.001). However, there was no significant difference in the maximum force applied by the novices to the mitral valve during suturing (P = 0.7) and suture tying (P = 0.6) using either 2D or 3D visualization. The mean time required and forces applied by both the experts and the novices were significantly less using the conventional surgical technique than when using the robotic system with either 2D or 3D vision (P < 0.001). Conclusions Despite high-quality binocular images, both the experts and the novices applied significantly more force to the cardiac tissue during 3D robotics-assisted mitral valve annuloplasty than during conventional open mitral valve annuloplasty. This finding suggests that 3D visualization does not fully compensate for the absence of haptic feedback in robotics-assisted cardiac surgery.

Sign in / Sign up

Export Citation Format

Share Document