Date

6-2016

Degree Name

BS in Mechanical Engineering

Department

Mechanical Engineering Department

Advisor(s)

Christoph Maurer

Abstract

The task of this project was to create an adaptive paddleboard capable of being ridden by someone who does not have full mobility in one or more of their lower extremities. This project was worked on by a team of five students - three mechanical engineers and two kinesiology students - to create an effective and robust design for the client. To do this, the team regularly met with the client and used individual and group expertise in various fields to bring the best product to the end user.

The client, Damien, was a firefighter who was injured in July 2015 after a tree fell on him while he was on duty. The incident left Damien with an incomplete spinal cord injury at level T12 and L1. An incomplete spinal cord injury differs from a complete spinal cord injury in that the spinal cord is not completely severed; instead, due to vertebrae compression or fracture, the axons of a nerve are crushed or destroyed, affecting the ability of motor or sensory information to be transmitted to the brain. However, because of the incomplete nature of the injury, some motor and sensory function is still preserved. The extent of sensory and/or motor preservation is highly varied from person to person because of the difference in the amount of damage on each person’s nerve fibers. Injuries to the L1 vertebrae commonly result in mild loss of function in the hips and legs. As is typical with these types of thoracic injuries, Damien retained full function and strength in his arms and hands. Damien began working on strengthening his legs and reestablishing patterned neural activity in the Central Nervous System (CNS) through intensive therapy at Project Walk in the third quarter of 2015. The therapy is an intensive physical therapy regime; with the goal of being able to walk by the time his therapy is completed.

The project was meant to be used by the client for the entirety of his therapy and beyond. For this, the team went through many designs and ideas before all settling on one style, a rear folding, low profile support that could assist the client in a standing position. This design went through a multitude of design changes and iterations as proof of concept tests and analysis was done throughout the year. Consultation with the client, sponsors, advisors, and those interested in the project or working on something similar were paramount helping the team finalize the design.

The final chosen design is a modified version of the preliminary selected design. Upon presenting the final preliminary design to Damien, the team received valuable feedback regarding how he planned to use the board, as well as his progress in his ability to move his legs. The largest change Damien wanted to see in the design was the addition of a seating position on the board, which became a focus for the team. Furthermore, Damien expressed how he was very comfortable using dip bars to move his body up and down, as this is a very common movement for wheelchair users. The team took this feedback, in addition to other items, and integrated them into the design in an attempt to create the product so it uniquely fit Damien’s desires.

One major breakthrough on the project was that of the insert design used to attach the structure to the board. Through research into methods to attaching structures to prefabricated paddleboards, there was no basis that could be found, as most products of this type were made building custom boards. For this project, and the help of SUP Think Tank and Ding King Surfboard Repair, the team used the “top hat” method, which consists of the following order for each of the four insert locations: two layers of carbon fiber sheets, three layers of 4 oz. fiberglass sheets, the wooden inserts, and then three more layers of 4 oz. fiberglass. Another major recognition was that of automated machining, where using CNC machines became a major help when having tried and failed and hand machining certain aspect of this project. All of this lead to the final design for the adaptive stand up paddleboard project.

The final design consists of three positions, kneeling, sitting, and standing. Movement between these positions is possible with the use of the dip bars Damien suggested, and the low profile idea from the initial concept was kept. This low profile concept allows the standing and sitting support to fold down against the paddleboard, also clearing room for a more comfortable kneeling position. The entire project was made marine compatible, with the structure being made of anodized aluminum, nylon straps, and stainless steel bolts and pins. This design was made modular, so it could be removed from the board if necessary, allowing the paddleboard to progress with the client throughout his recovery and more, assisting him in all areas necessary.

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