Dynamic Fatigue Machine
Hello! We are team Smooth Sailing, and we have designed and developed a unique and specialized way to fatigue sail material used for sailboats. Our sponsor North Sails, the number one manufacturer of sail boat sails in the world, contracted us to help them further their research and development of sail boat sails with this machine. Fatigue machines are unique in that they are used to test specific aspects of products. This dynamic fatigue machine will be used to fatigue the strands of material that make up a sail. This fatigued material will then be used by the North Sails engineering department to test the stress and strain of the fatigued material. North Sails will then be able to see how their material will react under strenuous loading conditions seen in the field. This will then help North Sails to innovate their sail designs and create a faster, stronger, and more reliable sail!
Phase I: Design Inputs
Phase I Overview
In Phase I, we looked at our user’s needs and developed project requirements based upon those needs. We identified the hazards associated with this project. We initiated the process of tracking our design with the DCTM (Design Control Trace Matrix). We designed initial concepts, and this is the phase where we began design for manufacturing. Phase I includes market research, however, at the moment there is not a similar product on the market. Below are a list of the required specifications for this project and some preliminary concept designs.
- Product must deliver impulse to sail material.
- Product must deliver max force of 1000 pound-seconds.
- Clamps must be used that can hold material with a coefficient of friction between .05-.08 (sail material) in tension.
- Clamps must hold material without compromising integrity of sample.
- Product must be calibratable to provide variable force and frequency. Product must operate for a range of force of 0-1000 lb.*s and a frequency of 0-4 Hz.
- Product must be able to fit in a 4’x 4’ area.
- Clamps must be easily accessible for operator to load and unload sail samples.
- Springs must be accessible for replacement.
- Hazard labels must be clearly visible.
- Product must have an instruction manual that determines how to inspect the machine for wear prior to each use.
Product requires a vibration damping pad of 0.5” rubber in at minimum four corners.
- Product must have an instruction manual that provides a proper training method to be conducted to ensure safe operation of the machine.
- Safety stops must be implemented that can withstand an impact force of 2500 pounds in the event that sail material breaks and machine must be capable to turn off instantly.
Proof of Concept
This proof of concept was built using a wood frame, and the intention was to test a camshaft mechanism for lifting the springs. However, we scrapped this idea and redesigned our whole project later.
Phase II: Design Outputs
Phase II Overview
In Phase II, we chose the concept we were going to develop that would satisfy all our product requirements, and we began design all the parts in SolidWorks. This included a top level assembly, sub-assemblies, and individual part drawings for each sub-assembly. Displayed below is the top level assembly along with the sub-assemblies. It’s important to note, that each sub-assembly is broken up in to individual parts. These parts were to be either ordered as off the shelf parts or machined by hand.
The machine was built in three sections and then assembled together. Below are the drawings of each sub-assembly.
Phase III: Verification and Validation
Phase III Overview
In Phase III, we began testing the machine to make sure it met all of our specifications. This included developing a test plan and protocol in order to give a guideline to the team about criteria to either pass or fail an aspect of the machine. If part of the machine were to fail, then we would need to go back to the design and revise part or parts of it in order to conform to a passing standard.
This is a slow motion video of the stress distribution in the sail material.
Phase IV: Manufacturing
Phase IV Overview
In Phase IV, we prepared our machine for manufacturing release. This involved preparing all documents and drawings to make sure everything was at the current revision level. In addition, we needed to make sure we had applicable regulatory requirements.
We first built the frame of the machine. This meant that we needed to first cut the 2″x2″ steel stock; we did this in the UNR machine shop. Next, we needed to align all the frame pieces and weld them together. Next we needed to machine parts for the motor and spring assemblies; this took the majority of our time. After all the machining was finished, we started assembly of the whole machine.
We were able to successfully complete the project. The machine effectively fatigues sail material until failure as shown in the picture below; our sponsor is satisfied with our results. The material broke in the ideal manner; it did not have stress concentrations where it was attached to the clamps. This is evident because the material broke near the center and the break has a hourglass shape. Overall, the product works as intended and will provide North Sails with valuable data about the fatigue life of their sails; better sail compositions will be able to be developed.
- Cycle counter
- Load Cell
- Environmental Testing (i.e. humidity, heat, cold, etc.)
Meet the Team
Izzy McGoff – Team Leader: Izzy is a senior mechanical engineering student graduating in the fall of 2016. Izzy aspires to be a design engineer in the action sports camera industry after graduation. Outside of school, Izzy enjoys a range of outdoor activities such as mountain biking, snowboarding, and hiking around the beautiful lake Tahoe area.
Dan Gonzales – Mechanical Engineer: Aspires to start his career in Reno after graduation. Dan has strong interests in design and hopes to find a mechanical engineering design position. Dan enjoys mountain biking in his free time and looks to pursue his P.E.
Kyle Willens – Mechanical Engineer: Kyle grew up in Carson City and came to Reno to study Mechanical Engineering at UNR. After graduation, Kyle plans to be a design engineer in the automotive industry; eventually, Kyle would like to start his own company. Outside of school, Kyle enjoys the many outdoor activities the Reno area has to offer; namely riding dirt bikes.
Trevor Bonie – Mechanical Engineer: Trevor is excited to graduate from UNR with a major in Mechanical Engineering and a minor in mathematics. After graduation, Trevor would like to explore being a design engineer for diverse projects. In his free time, Trevor enjoys being outdoors and doing hobbies such as skiing, camping, and off roading.
Professor Steven King
Tony Berendson – Machine Shop Supervisor
North Sails – Team Sponsor (Website)