Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
FINITE ELEMENT ANALYSIS OF THE MECHANICAL STRUCTURE OF AN HYBRID ORTHOSIS
Submission Author:
Francielle Paz , MG
Co-Authors:
Francielle Paz, Arthur Caetano, Matheus Carvalho Barbosa Costa, João Paulo Fernandes Bonfim, Guilherme de Paula Rúbio, Fernanda Márcia Rodrigues Martins Ferreira, Lucas Oliveira da Fonseca, HENRIQUE MARTINS, Claysson Vimieiro
Presenter: Francielle Paz
doi://10.26678/ABCM.COBEM2023.COB2023-1326
Abstract
The most common sequelae left by the Cerebrovascular Accident (CVA), popularly known as stroke, are motor limitations in the upper limb that hinder the independent performance of various daily activities by the affected individual. In order to alleviate these consequences, hybrid orthoses that combine mechanical systems with Functional Electrical Stimulation (FES) can be used in the rehabilitation of these individuals. The mechanical structure is of extreme importance for this system as it acts in conjunction with FES and plays the role of stabilizing the limb, ensuring that the extension and flexion of the elbow produced by electrical stimulation is functional, and enables the performance of daily activities by the user. Thus, the aim of this study is to validate the mechanical structure of a hybrid orthosis for upper limbs that is currently under development at the Laboratory of Bioengineering (LabBio) of UFMG in partnership with the National Institute for Research in Digital Science and Technology (INRIA) in France. The mechanical orthosis is made of aluminum alloy 1100 H14 and allows elbow extension and flexion in the range of 0º to 145º through a course limiter adapted to the user and made of polylactic acid (PLA). The project involves firstly a biomechanical analysis of a simulation performed using the Opensim software to collect the maximum torque on the elbow when an individual flexes the arm using the orthosis and holding a one-kilogram object. This type of analysis is little discussed in the literature, but brings great advantages to accelerate the study of the efforts that the body will apply on the orthosis, without invasive procedures and with very low cost. Using the data from the biomechanical analysis two static structural simulations were performed using the finite element method, to evaluate the consequences of the elbow torque, the center of mass, and other acting stresses, one only with the alloy structure and other also considering the course limiter. The result is a 120,38 MPa Von Mises maximum stress in the screw receiving the impact of the course limiter’s pin and a maximum elastic equivalent strain of 0,36%. After evaluating all the obtained parameters it was concluded that the orthosis structure and the course limiter designed, are capable of bearing the worst-case loading scenario.Therefore it was obtained a functional and safe orthosis for the users.
Keywords
OpenSim, Finite Element Method, biomechanics, Functional Electrical Stimulation FES, hybrid orthosis
