Finite Element Analysis of Piezoelectric Strips for Modifying Ankle Torques in Active Prosthetic Feet: A Pilot Study

2012 ◽  
Author(s):  
Thomas Powelson ◽  
Jingzhou (James) Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pilot Study ◽  
Gait Cycle ◽  
Electric Motors ◽  
Element Analysis ◽  
Prosthetic Foot ◽  
Ankle Torque ◽  
Novel Method ◽  
Prosthetic Feet

Over the last fifty years there has been a steady advance in prosthetic foot technologies. These advances have primarily focused on more accurately mimicking the biologic foot for amputees. One field of research currently being explored is active/powered prosthetic feet in which the movement of the foot is actively controlled through the use of electric motors. Some of these feet also seek to reproduce the ankle torques seen in the biologic foot. This paper proposes a novel method for more accurately reproducing these ankle torques through the use of piezoelectrics in conjunction with the electric motors. FEA software is used to simulate the modification of ankle torques through the use of piezoelectric bending actuators in a general case. A number of different configurations for the piezoelectric strips are examined to test the versatility of the piezoelectrics in this application. The general trends of the ankle torque vs gait cycle found in the literature have been reproduced in the simulations.

Stress Distribution in an Artificial Cruciate Ligament during the Gait Cycle

2014 ◽  
Vol 601 ◽  
pp. 167-170
Author(s):  
Lucian Bogdan ◽  
Cristian Sorin Nes ◽  
Angelica Enkelhardt ◽  
Nicolae Faur ◽  
Carmen Sticlaru ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Knee Joint ◽  
Gait Cycle ◽  
Cruciate Ligament ◽  
Element Analysis ◽  
Proposed Model

This paper presents a finite element analysis in order to determinate the stress distribution in an proposed model of the artificial cruciate ligament of the knee joint during the gait cycle.

scholarly journals Finite Element Analysis of Masticatory Stress on Neoformed Bone Tissue After Distraction Osteogenesis and Low-Level Laser Therapy: A Pilot Study

2014 ◽  
Vol 32 (8) ◽  
pp. 429-436
Author(s):  
Angelo Luiz Freddo ◽  
Eliete Biasotto Hauser ◽  
Victor Velho de Castro ◽  
Pedro Yoshito Noritomi ◽  
Alexandre Simões de Almeida ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pilot Study ◽  
Bone Tissue ◽  
Laser Therapy ◽  
Distraction Osteogenesis ◽  
Low Level Laser Therapy ◽  
Element Analysis ◽  
Level Laser ◽  
Masticatory Stress

scholarly journals Contact Stresses in a Fixed-Bearing Total Ankle Replacement

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002 ◽  
Author(s):  
Nicoló Martinelli ◽  
Silvia Baretta ◽  
Alberto Bianchi Castagnone Prati ◽  
Francesco Malerba ◽  
Carlo Corrado Bonifacini ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stance Phase ◽  
Gait Cycle ◽  
Contact Stresses ◽  
Von Mises Stress ◽  
Third Generation ◽  
Fixed Bearing ◽  
Element Analysis ◽  
Von Mises

Category: Ankle, Ankle Arthritis, Basic Sciences/Biologics Introduction/Purpose: Third-generation ankle implants with good clinical results continued to increase the popularity of total ankle arthroplasty (TAA) to address end-stage ankle osteoarthritis preserving joint movement. Newer TAA used fixed-bearing designs, with a theoretical increase of contact stresses leading to a higher polyethylene wear. The purpose of this study was to investigate the contact stresses in the polyethylene component of a new third-generation TAA, with a fixed-bearing design, using 3D finite element analysis. Methods: A three-dimensional finite element model was developed based on the Zimmer Trabecular Metal Total Ankle (ZTMTA) and a finite element analysis was employed to evaluate the contact pressure, contact area and Von Mises stress in the polyethylene articular surface in the stance phase of the gait cycle. Results: The peak values were found at the anterior regions of the articulating surface, where reached 19.8 MPa at 40% of gait cycle. The average contact pressure during the stance phase of gait was 6.9 MPa. The maximum von Mises stress of 14.1 MPa in the anterior section was reached at 40% of the gait cycle. For the central section the maximum von Mises stress of 10.8 MPa was reached at 37% of the gait cycle, whereas for posterior section the maximum of 5.4 MPa was reached at the end of the stance phase (60% of the gait cycle). Conclusion: Although, the average von Mises stress was less than 10 MPa, high peak pressure values were recorded. Advanced models to quantitatively estimate the wear are needed to assess polyethylene and metal component survivorship.

scholarly journals Study on Line-Start Permanent Magnet Assistance Synchronous Reluctance Motor for Improving Efficiency and Power Factor

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 384 ◽  
Author(s):  
Hyunwoo Kim ◽  
Yeji Park ◽  
Huai-Cong Liu ◽  
Pil-Wan Han ◽  
Ju Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Magnet ◽  
Power Factor ◽  
Permanent Magnets ◽  
Electric Motors ◽  
Element Analysis ◽  
Final Model ◽  
Synchronous Reluctance Motor ◽  
Reluctance Motor

In order to improve the efficiency, a line-start synchronous reluctance motor (LS-SynRM) is studied as an alternative to an induction motor (IM). However, because of the saliency characteristic of SynRM, LS-SynRM have a limited power factor. Therefore, to improve the efficiency and power factor of electric motors, we propose a line-start permanent magnet assistance synchronous reluctance motor (LS-PMA-SynRM) with permanent magnets inserted into LS-SynRM. IM and LS-SynRM are selected as reference models, whose performances are analyzed and compared with that of LS-PMA-SynRM using a finite element analysis. The performance of LS-PMA-SynRM is analyzed considering the position and length of its permanent magnet, as well as its manufacture. The final model of LS-PMA-SynRM is designed for improving the efficiency and power factor of electric motors compared with LS-SynRM. To verify the finite element analysis (FEA) result, the final model is manufactured, experiments are conducted, and the performance of LS-PMA-SynRM is verified.

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