Finite Element Analysis as a Tool for Parametric Prosthetic Foot Design and Evaluation. Technique Development in the Solid Ankle Cushioned Heel (SACH) Foot

AbstractToe joint is known as one of the critical factors in designing a prosthetic foot due to its nonlinear stiffness characteristic. This stiffness characteristic provides a general feeling of springiness in the toe-off and it also affects the ankle kinetics. In this study, the toe part of the prosthetic foot was designed to improve walking performance. The toe joint was implemented as a single part suitable for 3D printing. The various shape factors such as curved shape, bending space, auxetic structure, and bending zone were applied to mimic human foot characteristics. The finite element analysis (FEA) was conducted to simulate terminal stance (from heel-off to toe-off) using the designed prosthetic foot. To find the structure with characteristics similar to the human foot, the optimization was performed based on the toe joint geometries. As a result, the optimized foot showed good agreement with human foot behavior in the toe torque-angle curve. Finally, the simulation conditions were validated by comparing with human walking data and it was confirmed that the designed prosthetic foot structure can implement the human foot function.

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Design of 3D Printable Prosthetic Foot to Implement Nonlinear Stiffness Behavior of Human Toe Joint Based On Finite Element Analysis

10.21203/rs.3.rs-612083/v1 ◽

2021 ◽

Author(s):

Hui-Jin Um ◽

Heon-Su Kim ◽

Woolim Hong ◽

Hak-Sung Kim ◽

Pilwon Hur

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Nonlinear Stiffness ◽

Element Analysis ◽

Shape Factors ◽

Prosthetic Foot ◽

Human Foot ◽

Foot Structure ◽

General Feeling ◽

Foot Function

Abstract The toe joint is one of the critical factors in designing a prosthetic foot. This is because its nonlinear stiffness provides a general feeling of springiness in the toe-off and it also affects the ankle kinetics. In this study, the toe part of the prosthetic foot was designed to improve walking performance. The toe joint was implemented as a single part suitable for 3D printing. The various shape factors such as curved shape, bending space, auxetic structure, and bending zone were applied to mimic human foot characteristics. The finite element analysis (FEA) was conducted to simulate terminal stance (from heel-off to toe-off) using the designed prosthetic foot. To find the structure with characteristics similar to the human foot, the optimization was performed based on the toe joint geometries. As a result, the optimized foot showed good agreement with human foot behavior in the toe torque-angle curve. Finally, the simulation conditions were validated by comparing with human walking data and it was confirmed that the designed prosthetic foot structure can implement the human foot function.

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

Volume 4: 36th Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2012-71106 ◽

2012 ◽

Cited By ~ 1

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.

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