Stress and rigidity comparison and improved vibration control of flexible carbon-fiber and epoxy-glass composite manipulators under end-point load

2018 ◽  
Vol 6 (3) ◽  
pp. 035604
Author(s):  
Şahin Yavuz ◽  
Mehmet Mert İlman
Author(s):  
Femke M. Morsch ◽  
Nima Tolou ◽  
Just L. Herder

The objective of this paper is to present a comparative analysis for large deflections of a cantilever beam under free end point load. pseudo rigid body model (PRBM), non-linear beam theory numerically solved with integration (NLBT-NUM), linear beam theory (LBT), finite element modeling (FEM) using an available commercially FEM package, non-linear beam theory solved with direct nonlinear solution (NLBT-DNS) and experimental evaluation (EXP), have been implemented. For the purpose of comparison, the relation between the displacements, rotating angle of the tip and applied force were calculated and shown graphically. The accuracy of the path of the tip as a function of the force is compared with the NLBT-NUM, which is taken as a reference. In addition, computation times and implementation convenience were recorded. In the case of a perpendicular load, the PRBM is accurate and has little computation time. The NLBT-NUM, NLBT-DNS and FEM analysis are accurate, but the computation time is longer. The NLBT-DNS has been introduced for the first time and provides semi-exact closed form solutions for both horizontal and vertical position. In case of a non-perpendicular load, the NLBT-NUM and FEM analysis are the only accurate methods while computation time is less for the numerical solution. In conclusion, the PRBM and the FEM are recommended for the cases of perpendicular load and non-perpendicular load respectively. Finally, it can be concluded that the more accurate methods take more computation time, and that the accuracy is affected by load cases.


2016 ◽  
Vol 41 (5) ◽  
pp. 463-468 ◽  
Author(s):  
Christina M Webber ◽  
Kenton Kaufman

Background:Dynamic elastic response prosthetic feet are designed to mimic the functional characteristics of the native foot/ankle joint. Numerous designs of dynamic elastic response feet exist which make the prescription process difficult, especially because of the lack of empirical evidence describing the objective performance characteristics of the feet.Objectives:To quantify the mechanical properties of available dynamic elastic response prosthetic feet, specifically the stiffness and hysteresis.Study design:Mechanical testing of dynamic elastic response prosthetic feet.Methods:Static Proof Testing in accordance with ISO 10328 was conducted on seven dynamic elastic response prosthetic feet. Load–displacement data were used to calculate the instantaneous stiffness in both the heel and forefoot regions, as well as hysteresis associated with each foot.Results:Heel stiffness was greater than forefoot stiffness for all feet. The heel of the glass composite prosthetic foot was stiffer than the carbon fiber feet and it exhibited less hysteresis. Two different carbon fiber feet had the stiffest forefoot regions.Conclusion:Mechanical testing is a reproducible method that can be used to provide objective evidence about dynamic elastic response prosthetic foot performance and aid in the prescription process.Clinical relevanceThe quantitative stiffness and hysteresis data from this study can be used by prosthetists to aid the prescription process and make it more objective.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Atul ◽  
G. Divya Deepak

Abstract In the present work, vibration control of a simply supported plate with line type and cross type piezoelectric (PZT) patches are investigated with and without actuation voltage. The plate is modeled under the assumption of Kirchhoff’s Plate theory. The mass of PZT patches remain constant in all cases. In case of actuation, applied voltage considered are 1, 2 and 3 mV. The external excitation to the plate is in the form of harmonically varying point load of 1 mN. It is noticed that cross type PZT patch is more effective in deflection suppression of plate than that of line type PZT patch at 3 mV of actuation at patch thickness of 0.75 μm. Suppression of central deflection of plate for line type and cross type PZT patches are obtained in different frequency bands of (175–185 Hz) and (870–880 Hz) respectively.


Retrofitting materials like aluminum bars, steel overlays and glass fiber mixes has been utilized in the development field for a long time. Carbon fiber mixes are the ongoing expansion to the retrofitting materials. Trial and expository investigation have been done and compared.Total number of 6 shafts yet of which 3 are control bars and the other 3 pillars pre harmed 70%of extreme burden and after that enveloped by the base with CFRP laminates.Experimental examination completed by applying two-point load. Investigative examination by FEM specifically utilizing ABAQUS the predications utilizing the proposed diagnostic model are in great concurrence with the exploratory outcomes


1997 ◽  
Vol 58 (9) ◽  
pp. 1443-1449 ◽  
Author(s):  
Yoshihiro Hirata ◽  
Yasuo Fukushige ◽  
Hiroshi Kuwazuru ◽  
Ryoko Yamashita ◽  
Soichiro Sameshima ◽  
...  

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