scholarly journals Development of a Passive Prosthetic Hand That Restores Finger Movements Made by Additive Manufacturing

2020 ◽  
Vol 10 (12) ◽  
pp. 4148
Author(s):  
Rodrigo Cézar da Silveira Romero ◽  
André Argueso Machado ◽  
Kliftom Amorim Costa ◽  
Paulo Henrique Rodriguês Guilherme Reis ◽  
Pedro Paiva Brito ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Additive Manufacturing ◽  
Tensile Testing ◽  
Maximum Stress ◽  
Low Cost ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Plastic Deformations ◽  
Printing Parameters

This work aims to develop a low-cost human hand prosthesis manufactured through additive manufacturing. The methodology used for the development of the prosthesis used affordable and low-cost materials in the market. Tensile testing was performed to estimate the mechanical properties in order to verify the resistance of the printing material used. Afterwards, the mechanical feasibility study executed on the device was performed using finite element method. In conclusion, we can observe fundamental factors that influence the 3D printing process, especially in relation to its printing parameters and mechanical properties. Maximum stress, yield stress, modulus of elasticity, elongation, and hardness are the prominent properties that should be considered when choosing the polymeric material. The numerical simulation showed that the structure of the prosthesis did not present plastic deformations to the applied loads, proving its mechanical viability.

scholarly journals Application of an Additive Manufactured Hybrid Metal/Composite Shock Absorber Panel to a Military Seat Ejection System

2021 ◽  
Vol 11 (14) ◽  
pp. 6473
Author(s):  
Valerio Acanfora ◽  
Chiara Corvino ◽  
Salvatore Saputo ◽  
Andrea Sellitto ◽  
Aniello Riccio
Keyword(s):  
Numerical Simulation ◽  
Additive Manufacturing ◽  
Total Mass ◽  
Shock Absorber ◽  
Metal Composite ◽  
Plastic Deformations ◽  
Shock Absorbers ◽  
Numerical Assessment ◽  
Lattice Core ◽  
Ejection Phase

In this work, a preliminary numerical assessment on the application of an additive manufactured hybrid metal/composite shock absorber panels to a military seat ejection system, has been carried out. The innovative character of the shock absorber concept investigated is that the absorbing system has a thickness of only 6 mm and is composed of a pyramid-shaped lattice core that, due to its small size, can only be achieved by additive manufacturing. The mechanical behaviour of these shock absorber panels has been examined by measuring their ability to absorb and dissipate the energy generated during the ejection phase into plastic deformations, thus reducing the loads acting on pilots. In this paper the effectiveness of a system composed of five hybrid shock absorbers, with very thin thickness in order to be easily integrated between the seat and the aircraft floor, has been numerically studied by assessing their ability to absorb the energy generated during the primary ejection phase. To accomplish this, a numerical simulation of the explosion has been performed and the energy absorbed by the shock-absorbing mechanism has been assessed. The performed analysis demonstrated that the panels can absorb more than 60% of the energy generated during the explosion event while increasing the total mass of the pilot-seat system by just 0.8%.

scholarly journals Design and multichannel electromyography system-based neural network control of a low-cost myoelectric prosthesis hand

2021 ◽  
Vol 12 (1) ◽  
pp. 69-83
Author(s):  
Saygin Siddiq Ahmed ◽  
Ahmed R. J. Almusawi ◽  
Bülent Yilmaz ◽  
Nuran Dogru
Keyword(s):  
Neural Network ◽  
Control Method ◽  
Low Cost ◽  
Hand Movement ◽  
Cost Effective ◽  
Network Control ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Myoelectric Prosthesis ◽  
System File

Abstract. This study introduces a new control method for electromyography (EMG) in a prosthetic hand application with a practical design of the whole system. The hand is controlled by a motor (which regulates a significant part of the hand movement) and a microcontroller board, which is responsible for receiving and analyzing signals acquired by a Myoware muscle device. The Myoware device accepts muscle signals and sends them to the controller. The controller interprets the received signals based on the designed artificial neural network. In this design, the muscle signals are read and saved in a MATLAB system file. After neural network program processing by MATLAB, they are then applied online to the prosthetic hand. The obtained signal, i.e., electromyogram, is programmed to control the motion of the prosthetic hand with similar behavior to a real human hand. The designed system is tested on seven individuals at Gaziantep University. Due to the sufficient signal of the Mayo armband compared to Myoware sensors, Mayo armband muscle is applied in the proposed system. The discussed results have been shown to be satisfactory in the final proposed system. This system was a feasible, useful, and cost-effective solution for the handless or amputated individuals. They have used the system in their day-to-day activities that allowed them to move freely, easily, and comfortably.

scholarly journals Suitability of Recycled PLA Filament Application in Fused Filament Fabrication Process

2021 ◽  
Vol 15 (4) ◽  
pp. 491-497
Author(s):  
Tomislav Breški ◽  
Lukas Hentschel ◽  
Damir Godec ◽  
Ivica Đuretek
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Polylactic Acid ◽  
Design Of Experiment ◽  
Experimental Approach ◽  
Manufacturing Processes ◽  
Support Structures ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
Printing Parameters

Fused filament fabrication (FFF) is currently one of the most popular additive manufacturing processes due to its simplicity and low running and material costs. Support structures, which are necessary for overhanging surfaces during production, in most cases need to be manually removed and as such, they become waste material. In this paper, experimental approach is utilised in order to assess suitability of recycling support structures into recycled filament for FFF process. Mechanical properties of standardized specimens made from recycled polylactic acid (PLA) filament as well as influence of layer height and infill density on those properties were investigated. Optimal printing parameters for recycled PLA filaments are determined with Design of Experiment methods (DOE).

scholarly journals Modeling and Analysis of a Visual Feedback System to Support Efficient Object Grasping of an EMG-Controlled Prosthetic Hand

2019 ◽  
Vol 5 (1) ◽  
pp. 207-210
Author(s):  
Tolgay Kara ◽  
Ahmad Soliman Masri
Keyword(s):  
Visual Feedback ◽  
Low Cost ◽  
Feedback System ◽  
Hand Gesture ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Modeling And Analysis ◽  
Prosthetic Hands ◽  
Prosthetic Limbs ◽  
Computer Environment

AbstractMillions of people around the world have lost their upper limbs mainly due to accidents and wars. Recently in the Middle East, the demand for prosthetic limbs has increased dramatically due to ongoing wars in the region. Commercially available prosthetic limbs are expensive while the most economical method available for controlling prosthetic limbs is the Electromyography (EMG). Researchers on EMG-controlled prosthetic limbs are facing several challenges, which include efficiency problems in terms of functionality especially in prosthetic hands. A major issue that needs to be solved is the fact that currently available low-cost EMG-controlled prosthetic hands cannot enable the user to grasp various types of objects in various shapes, and cannot provide the efficient use of the object by deciding the necessary hand gesture. In this paper, a computer vision-based mechanism is proposed with the purpose of detecting and recognizing objects and applying optimal hand gesture through visual feedback. The objects are classified into groups and the optimal hand gesture to grasp and use the targeted object that is most efficient for the user is implemented. A simulation model of the human hand kinematics is developed for simulation tests to reveal the efficacy of the proposed method. 80 different types of objects are detected, recognized, and classified for simulation tests, which can be realized by using two electrodes supplying the input to perform the action. Simulation results reveal the performance of proposed EMG-controlled prosthetic hand in maintaining optimal hand gestures in computer environment. Results are promising to help disabled people handle and use objects more efficiently without higher costs.

A custom, functional and lifelike passive prosthetic hand for infants and small toddlers: Clinical note

2020 ◽  
Vol 44 (3) ◽  
pp. 180-184
Author(s):  
Arezoo Eshraghi ◽  
Jaeeun Yoo ◽  
James Klein ◽  
Ian Mckenzie ◽  
Gabrielle Sebaldt ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Upper Limb ◽  
Low Cost ◽  
Prosthetic Hand ◽  
Functional Requirements ◽  
Infants And Toddlers ◽  
Clinical Note ◽  
Alloy Wire ◽  
Prosthetic Hands ◽  
Limb Deficiencies

Background and Aim: For infants and small toddlers with congenital upper limb deficiencies, terminal devices mainly provide either cosmesis or functionality. We report a clinical note about fitting a child with a low-cost passive hand targeting both functionality and cosmesis. Technique: An elastomeric, alloy-wire-reinforced hand was fabricated using additive manufacturing to allow independent positioning of the digits. A clinical pilot in-home evaluation was conducted on a child with upper limb loss. Discussion: The fabricated hand met the functional requirements but required a cover for cosmesis due to a poor surface finish associated with the fabrication technique. The participant child was comfortable using the prosthesis for various tasks. The parents were satisfied with the hand’s function and cosmesis when covered with a cosmetic glove. This work demonstrated a new design and process that may in the future improve the utilization of prosthetic hands to promote early prosthesis use and a child’s development. Clinical relevance Early prosthesis use is important for infants and toddlers. Additive manufacturing may enable the fabrication of custom passive prosthetic hands that provide both cosmesis and functionality.

scholarly journals Design, Construction and Tests of a Low-Cost Myoelectric Thumb

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 63
Author(s):  
Murat Ayvali ◽  
Inge Wickenkamp ◽  
Andrea Ehrmann
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Low Cost ◽  
The Body ◽  
Human Hand ◽  
Typical Application ◽  
Myoelectric Prostheses ◽  
Manual Tasks ◽  
Recent Project ◽  
Design Construction

Myoelectric signals can be used to control prostheses or exoskeletons as well as robots, i.e., devices assisting the user or replacing a missing part of the body. A typical application of myoelectric prostheses is the human hand. Here, the development of a low-cost myoelectric thumb is described, which can either be used as an additional finger or as prosthesis. Combining 3D printing with inexpensive sensors, electrodes, and electronics, the recent project offers the possibility to produce an individualized myoelectric thumb at significantly lower costs than commercial myoelectric prostheses. Alternatively, a second thumb may be supportive for people with special manual tasks. These possibilities are discussed together with disadvantages of a second thumb and drawbacks of the low-cost solution in terms of mechanical properties and wearing comfort. The study shows that a low-cost customized myoelectric thumb can be produced in this way, but further research on controlling the thumb as well as improving motorization are necessarily to make it fully usable for daily tasks.

Validation of a low-cost selective powder deposition process through the characterization of tin bronze specimens

2021 ◽  
pp. 146442072110319
Author(s):  
Samuel Magalhães ◽  
Manuel Sardinha ◽  
Carlos Vicente ◽  
Marco Leite ◽  
Relógio Ribeiro ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Low Cost ◽  
Deposition Process ◽  
Metal Powders ◽  
Tin Bronze ◽  
Powder Deposition ◽  
Manufacturing Technologies ◽  
The Cost

Additive manufacturing technologies are becoming increasingly popular due to their advantages over traditional subtracting manufacturing technologies. Despite advances in this field, fixed and maintenance costs for additive manufacturing with metals remain high. The introduction of low-cost metal machines in the additive manufacturing market considerably reduces the cost of acquiring and maintaining this type of equipment. This work aims to establish the process requirements for a low-cost selective powder deposition process, and validate it through the production of specimens in the laboratory and evaluate their mechanical properties. Tin bronze specimens were produced under different manufacturing conditions, namely powder dimensions, type of crucible and coke, firing segments and casting strategy. The morphology and chemical composition of the specimens were carried out combining the scanning electron microscopy and energy dispersive X-Ray spectroscopy techniques, respectively. It was observed that crucibles and coke with impurities that react with the metal powders and infill in a reducing atmosphere have influence in the final quality of parts. Tested samples displayed high variability of results which can be correlated with different manufacturing conditions. The selection of the appropriate print parameters led to the manufacture of tin bronze specimens with mechanical properties comparable to those reported in the literature. Overall, low-cost selective powder deposition is a promising technology, if identified manufacturing issues are addressed.

scholarly journals A Sensitivity Analysis-Based Parameter Optimization Framework for 3D Printing of Continuous Carbon Fiber/Epoxy Composites

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3961 ◽  
Author(s):  
Hong Xiao ◽  
Wei Han ◽  
Yueke Ming ◽  
Zhongqiu Ding ◽  
Yugang Duan
Keyword(s):  
Mechanical Properties ◽  
Sensitivity Analysis ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Flexural Modulus ◽  
Epoxy Composites ◽  
Optimization Framework ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Epoxy ◽  
Printing Parameters

Three-dimensional printing of continuous carbon fiber/epoxy composites (CCF/EPCs) is an emerging additive manufacturing technology for fiber-reinforced polymer composites and has wide application prospects. However, the 3D printing parameters and their relationship with the mechanical properties of the final printed samples have not been fully investigated in a computational and quantifiable way. This paper presents a sensitivity analysis (SA)-based parameter optimization framework for the 3D printing of CCF/EPCs. A surrogate model for a process parameter–mechanical property relationship was established by support vector regression (SVR) analysis of the experimental data on flexural strength and flexural modulus under different process parameters. An SA was then performed on the SVR surrogate model to calculate the importance of each individual 3D printing parameter on the mechanical properties of the printed samples. Based on the SA results, the optimal 3D printing parameters and the corresponding flexural strength and flexural modulus of the printed samples were predicted and verified by experiments. The results showed that the proposed framework can serve as a high-accuracy tool to optimize the 3D printing parameters for the additive manufacturing of CCF/EPCs.

scholarly journals Preparation of Linear Low-density Polyethylene/Treated Date Palm Leaflet Green Composites and Investigation of their Thermal and Mechanical Properties

2019 ◽  
Vol 35 (1) ◽  
pp. 200-206
Author(s):  
Mashael Alshabanat
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Date Palm ◽  
Low Cost ◽  
Gum Arabic ◽  
Renewable Resource ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Thermal And Mechanical Properties ◽  
Linear Low Density Polyethylene

This work aims to develop green linear low-density polyethylene (LLDPE) composites that are commercially viable due to the low cost of the date palm leaflet filler, which is a local renewable resource. The filler was naturally treated with gum arabic solution. FT-IR, XRD, and SEM techniques were used to characterize the samples. The thermal and mechanical properties were measured by TGA, DSC, and tensile testing. The results showed noticeable changes in the properties of the composites compared to those of the original LLDPE sample. TGA revealed that the composite started thermally. The composites started thermally degrading before the original polymer, owing to the degradation of the natural components in the filler. The findings from DSC suggested that the crystallinity was affected. The tensile testing results indicated that the composites were appropriate for applications requiring low tensile strength at break and high Young’s modulus. A comparison of these results with earlier ones exhibited that the basic additives in the polymer may have an effect on the filler performance.

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