Modeling the design of a stand for restoring hand strength for people with disabilities
Students Name: Ilnytskyi Ostap Anatoliiovych
Qualification Level: magister
Speciality: Computer Engineering in Mechanical Engineering
Institute: Institute of Mechanical Engineering and Transport
Mode of Study: full
Academic Year: 2023-2024 н.р.
Language of Defence: ukrainian
Abstract: The main problems of people with disabilities are rehabilitation after an injury and further adaptation to society. Most people with disabilities lead an active lifestyle, but still need opportunities for rehabilitation, in particular, body muscles that have weakened due to being confined to a wheelchair. One way is to purchase your own exercise equipment and use it at home without any additional complications. However, professional equipment is too expensive and takes up a lot of space. But most importantly, it is not adapted for people with disabilities, so their use by disabled people is difficult or completely impossible. The market for such products is not sufficiently developed. Not all products can boast of compatibility, ergonomics that correspond to different forms of disability, or a favorable ratio of price and quality of construction. The object of research: features of functioning and substantiation of criteria affecting the design of nodes and elements of the designed universal stand for restoring the strength of people’s hands. The subject of the study: geometric, kinematic and power parameters of the stand nodes for restoring the strength of the hands of people with disabilities. The purpose of the study – development of a universal stand for restoring the strength of the hands of people with disabilities. The first section of the work deals with the design of a universal home hand strengthening stand for people with disabilities. Among the criteria that directly affect the design, it is worth noting the attachment of the stand to the wall in the house of a person with disabilities. The reason is that if a person, regardless of their health condition, ends up in a wheelchair, they want to be as self-sufficient as possible after treatment and are expected to find barrier-free accommodation. The second criterion includes a combination of training exercises that should ensure the loading of muscle parts weakened by a long stay in a wheelchair. The correct frame geometry is justified so that the stand settings are suitable for people of different heights and different wheelchair seat heights. A graphical analysis of the height and range of stand settings was carried out. As a result of this, the use of two guide polished profiles, which guide the sleeve with a rotary support of the three-roller system for variable adjustment of the handle position, is justified. Control elements have been developed that enable the use of the stand by people with tetraplegia. As a result, it was not possible to use standard locking pins with ball ends, so a special form of locking pin was developed. The set of weights had to be moved to a height of 315 mm from the floor plane (the minimum reach of a person from a wheelchair). The designed stand is equipped with only one set of loads. The advantage of this solution is the independence of the height of the left and right handrails. The hinged lever of the pedal is freely connected to the frame of the polyspast, which is implemented by a friction brake with a flywheel. The advantage of the pedal design is that the flywheel is placed on two tension wheels (self-centering). This allows you to rotate only one pedal. The movement of the pedal lever is provided by a hydropneumatic rack, the movement of which can be fixed with a button in any position during extension and retraction. The result of finite element modeling shows the maximum stress on the upper part of the welded frame structure is 48.1 MPa. If the frame material is used - S235JHR with yield strength Re = 235 MPa, the margin of strength is 4.9 times. In the fourth section of the work, an economic evaluation of the received design solution is carried out. In order to evaluate the obtained design solution from the economic side, the master’s thesis carried out planning of the execution of the master’s work and a number of relevant calculations: costs for its implementation, operating costs for the received design solution, determination of the consumption price of the design solution. According to calculations, the term of development and implementation of the design solution will be 90 days, for the costs of development and implementation of the design solution - UAH 41615,56. This project solution can be used for 5 years. The amount of annual operating costs for the design solution will be UAH 38905,00/year, the daily consumption price of the design solution for the developer organization will be UAH 143,47, for the buyer organization, UAH 145,59. Key words: hand strength, finite element method, modeling, geometric parameters, Autodesk Inventor, maximum stress, structural strength.