Visualization of principal strain direction by a mechanical device

Measurement ◽  
2020 ◽  
Vol 164 ◽  
pp. 108069
Author(s):  
Haihua Zhang ◽  
Shinichi Akutagawa ◽  
Kun Feng
Keyword(s):  
Principal Strain ◽  
Mechanical Device ◽  
Strain Direction

An Analysis of Microband Orientation in Hot Deformed Aluminium Alloy AA5052 Using Forward and Reverse Torsion

2006 ◽  
Vol 519-521 ◽  
pp. 877-882
Author(s):  
M. Lopez-Pedrosa ◽  
Bradley P. Wynne ◽  
Mark W. Rainforth ◽  
P. Cizek
Keyword(s):  
Strain Path ◽  
Electron Backscatter Diffraction ◽  
Principal Strain ◽  
The Maximum Principle ◽  
Stress Direction ◽  
Resolution Electron ◽  
Macroscopic Deformation ◽  
Backscatter Diffraction ◽  
Macroscopic Orientation ◽  
Strain Direction

The effects of strain path reversal on the macroscopic orientation of microbands in AA5052 have been studied using high resolution electron backscatter diffraction. Deformation was carried using two equal steps of forward/forward or forward/reverse torsion at a temperature of 300°C and strain rate of 1s-1 to a total equivalent tensile strain of 0.5. In both cases microbands were found in the majority of grains examined with many having more than one set. The microbands appear to cluster at specific angles to the macroscopic deformation. For the forward/forward condition microbands clustered around -20° and +45° to the maximum principle stress direction and at ± 30-35° to the principal strain direction. For the forward/reverse condition significantly more spread in microband angle was observed though peaks were visible at ±35° with respect to principal stress direction and at -40° and +30° with respect to the principal strain direction of the reverse torsion. This suggests the microbands formed in the forward deformation have or are dissolving and any new microbands formed are related to the deformation conditions of the final strain path.

DESIGN OF A MECHANICAL DEVICE FOR REDUCING NOISE AND ISSUANCE OF GAS AND PARTICLES FOR DIESEL ENGINES FROM AN ENERGY GENERATING ENGINE

2018 ◽  
Author(s):  
Herivaldo Pascoal ◽  
Domingos Sávio Tavares Mendes Junior ◽  
ANTONILSON CONCEIÇÃO ◽  
Yves Bandeira ◽  
Carlisson Azevedo ◽  
...  
Keyword(s):  
Diesel Engines ◽  
Mechanical Device

A topological approach to the strain-rate pattern of ice sheets

1993 ◽  
Vol 39 (131) ◽  
pp. 10-14 ◽  
Author(s):  
J. F. Nye
Keyword(s):  
Strain Rate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Point Of View ◽  
Principal Strain ◽  
Topological Approach ◽  
Contour Maps ◽  
Isotropic Point ◽  
Horizontal Strain

AbstractThe pattern of horizontal strain rate in an ice sheet is discussed from a topological point of view. In a circularly symmetric ice sheet, the isotropic point for strain rate at its centre is degenerate and structurally unstable. On perturbation the degenerate point splits into two elementary isotropic points, each of which has the lemon pattern for the trajectories of principal strain rate. Contour maps of principal strain-rate values are presented which show the details of the splitting.

Sliding Mode Control of an Actuated Knee Joint Orthosis

2021 ◽  
Vol 15 ◽  
Author(s):  
Imen Saidi ◽  
Asma Hammami
Keyword(s):  
Sliding Mode Control ◽  
Lower Limb ◽  
Sliding Mode ◽  
Position Tracking ◽  
Sliding Mode Controller ◽  
Mechanical Device ◽  
Tracking Errors ◽  
Mode Control ◽  
Speed Tracking ◽  
Human Morphology

Introduction: In this paper, a robust sliding mode controller is developed to control an orthosis used for rehabilitation of lower limb. Materials and Methods: The orthosis is defined as a mechanical device intended to physically assist a human subject for the realization of his movements. It should be adapted to the human morphology, interacting in harmony with its movements, and providing the necessary efforts along the limbs to which it is attached. Results: The application of the sliding mode control to the Shank-orthosis system shows satisfactory dynamic response and tracking performances. Conclusion: In fact, position tracking and speed tracking errors are very small. The sliding mode controller effectively absorbs disturbance and parametric variations, hence the efficiency and robustness of our applied control.

Validation of three‐dimensional echocardiographic principal strain analysis for assessing left ventricular contractility: An animal study

2019 ◽  
Vol 46 (5) ◽  
pp. 2137-2144
Author(s):  
Sahmin Lee ◽  
Seunghyun Choi ◽  
Sehwan Kim ◽  
Yeongjin Jeong ◽  
Kyusup Lee ◽  
...  
Keyword(s):  
Animal Study ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Left Ventricular ◽  
Principal Strain ◽  
Ventricular Contractility ◽  
Left Ventricular Contractility

scholarly journals Accuracy of cup placement in total hip arthroplasty by means of a mechanical positioning device: a comprehensive cadaveric 3d analysis of 16 specimens

2019 ◽  
pp. 112070001987482
Author(s):  
Arthur J Kievit ◽  
Johannes G G Dobbe ◽  
Wouter H Mallee ◽  
Leendert Blankevoort ◽  
Geert J Streekstra ◽  
...  
Keyword(s):  
3D Models ◽  
Safe Zone ◽  
3D Analysis ◽  
Anterior Pelvic Plane ◽  
Mechanical Device ◽  
Acetabular Cup ◽  
Anteversion Angle ◽  
Positioning Device ◽  
The Mean ◽  
Safe Zones

Introduction: We tested whether a mechanical device (such as Hipsecure) to pinpoint the anterior pelvic plane (APP) as a guide can improve acetabular cup placement. To assess accuracy we asked: (1) is the APP an effective guide to position acetabular cup placement within acceptable ° of divergence from the optimal 40° inclination and 15° anteversion; (2) could a mechanical device increase the number of acetabular cup placements within Lewinnek’s safe zone (i.e. inclination 30° to 50°; anteversion 5° to 25°)? Methods: 16 cadaveric specimens were used to assess the 3D surgical success of using a mechanical device APP to guide acetabular cup placement along the APP. We used the Hipsecure mechanical device to implant acetabular cups at 40° inclination and 15° anteversion. Subequently, all cadaveric specimens with implants were scanned with a CT and 3D models were created of the pelvis and acetabular cups to assess the outcome in terms of Lewinnek’s safe zones. Results: The mean inclination of the 16 implants was 40.6° (95% CI, 37.7–43.4) and the mean anteversion angle was 13.4° (95% CI, 10.7–16.1). All 16 cup placements were within Lewinnek’s safe zone for inclination (between 30° and 50°) and all but 2 were within Lewinnek’s safe zone for anteversion (between 5° and 25°). Conclusion: In cadaveric specimens, the use of a mechanical device and the APP as a guide for acetabular cup placement resulted in good positioning with respect to both of Lewinnek’s safe zones.

Development of PZT fiber rosette to locate acoustic source

2021 ◽  
pp. 1045389X2199192
Author(s):  
Bao Chi Ha ◽  
Kevin Gilbert ◽  
Gang Wang
Keyword(s):  
Lead Zirconate Titanate ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Lead Zirconate ◽  
Acoustic Source ◽  
Mechanical Coupling ◽  
Monitoring Applications ◽  
Commercial Off The Shelf ◽  
Lamb Wave Propagation ◽  
Strain Direction

Because of their electro-mechanical coupling property, Lead-Zirconate-Titanate (PZT) materials have been widely used for ultrasonic wave sensing and actuation in structural health monitoring applications. In this paper, a PZT rosette concept is proposed to conduct Lamb wave-based damage detection in panel-like structures by exploring its best directional sensing capability. First, a directivity study was conducted to investigate sensing of flexural Lamb wave propagation using a PZT fiber having d33 effects. Then, commercial off-the-shelf PZT fibers were polarized in-house in order to construct the PZT rosette configuration, in which three PZT fibers are oriented at 0°, 45°, 90°, respectively. Since Lamb wave responses are directly related to measured PZT fiber voltage signals, a simple interrogation scheme was developed to calculate principal strain direction in order to locate an acoustic source. Comprehensive tests were conducted to evaluate the performance of the proposed PZT rosette using an aluminum plate. It is shown that the PZT rosette is able to sense Lamb wave responses and accurately locate an acoustic source. We expect to further evaluate the PZT rosette performance when damages are introduced.

An electro-opto-mechanical device to make diffractive optical elements

2011 ◽  
Author(s):  
Jorge Castro-Ramos ◽  
Gabriel Gordiano-Alvarado ◽  
Carlos M. Ortiz-Lima ◽  
M. Antonio De-Jesus-Ortiz ◽  
Sergio Vazquez-Montiel ◽  
...  
Keyword(s):  
Diffractive Optical Elements ◽  
Mechanical Device ◽  
Optical Elements
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