Assignment #5
Problem Statement: Develop a mechanical device that lifts a camera up to at least eye level so that it can be used for pipe inspections inside of a nuclear power plant.
Decision Matrix: Creating this decision matrix helped me to pick which module to pursue. I picked criteria that was technical, but not overly specific. The utility was an important aspect within my designs because I wanted what I ended up making to be both usable and necessary. Another important criterion was efficiency. Since my modules explored different ways to operate, the tether spool efficiency was a valid and important criteria to explore.
Weights vary from 1-5 with 1 being the lowest and 5 being the best rating each aspect can achieve.
The clear winner from this matrix was the belt and pulley system. Looking back on my calculations from the module stage, it was clear that the belt and pulley system was hands down the most efficient. It also scored well with utility and reliability.
Module 3 Belt and Pulley was Chosen
Assumptions:
Some of the same assumptions from the modules carried over along with a few new assumptions. These include the overall size of the assembly as well as the length of cables that it needed to wind up.
The Engineering ToolBox was referenced for factors of safety and Young's Modulus of ABS.
Some outside parts were used for the sake of creating renderings of the modules.
Bearing from McMaster-Carr 60355K505
Stepper Motor 23HS41-1804S
The Design (3D models):
Complete model portfolio for this assignment.
Component 1 Spool:
An in-depth analysis was considered to come up with the correct sizing. Parametric design techniques were utilized to create equations that could later be easily edited to change things such as the outer diameter of the spool. A one-way bearing was designed into the spool to allow for free motion in one direction and motorized motion in the other.
FREDPARC Component 1:
Material Choice:
ABS material was picked as an easy-to-manufacture plastic with adequate properties to withstand the required stress.
Analysis:
A safety factor of 2 was chosen.
Forces, stresses, and deflection were analyzed.
It was found that the design needed to allow for maximum shear stress in the spool of 4.96psi.
Maximum normal stress in the spool was found to be 4psi.
The deflection in the spool was found to be an insignificant number of 2.31x10^-9in, showing that the material choice of ABS should be sufficiently strong.
Parametric equations:
Strategic aspects of the design were put in equation form so that it could be easily edited later on. These included the outer diameter of the spool, the inner diameter, and the width.
Renderings of the Component:
Component 2 Frame:
This component focuses on the frame that holds the spool. This utilizes bearings to guide the spool and reduce friction.
FREDPARC Component 2:
Material:
Aluminum T6-6061 was chosen as the choice material. The Young's Modulus was found to be E=10x10^6psi.
Analysis:
As before Forces, Stress, and power were analyzed, but in this case gear ratios and required motor torque were also determined.
It was found that the design needed to allow for maximum shear stress in the clamping bolts of 81.49psi.
PV calculations for the bearing came out to be 5.236 psi-fpm. This meant that most materials would have no issues with supporting the force by the bearing. A good bearing material to use would be Teflon (TFE) due to its self-lubricating properties.
The normal stress in the base plate is 0.615psi
The deflection in the baseplate was calculated to be 6.154x10^-8in
Parametric Equations
The general size of the frame was created using parametric equations for easy manipulation later on.
Renderings of the Module:
Component 3 Belt & Pulley:
Component 3 focused on the belt and pulley system used to interface with the spool and motor in winding up the spool.
FREDPARC Component 3:
Material:
Pulleys made from ABS plastic.
Steel core GT2 Belts 15mm width 5mm - GT®2 Timing Belts
Analysis:
The Modulus of Structural ASTM-A36 steel is 200GPa.
A safety factor of 2 was chosen.
Forces, stresses, and deflection was analyzed.
It was found that the design needed to allow for maximum shear stress in the motor shaft of 91.42psi.
Maximum normal stress in the shaft was found to be 782.28psi.
The deflection in the spool was found to be an insignificant number of 9.142x10^-9in showing that the belt size choice is more than enough to support the load without failure.
Parametric Equations:
The pulley system was designed as a single part file that could be edited with parametric equations. Both gears could be resized as well as the belt length.
Renderings of the Module:
Gantt Chart:
Download here
Lessons learned:
During this assignment, I learned the importance of material choices. This came into play during the calculations portion and I researched different materials and applied their values to my calculations.
Time Management:
11-20-2020 10:30 am-12:00 pm brainstorming and initial decision matrix implementation
11-23-2020 2:00-5:00 am sketches, equations, and writing
11-25-2020 3:00-7:00 pm Solidworks website implementation
12-1-2020 2:30-3:00 pm feedback
Comments to Advisees:
Advise to Dylan Appleyard:
Overall your assignment looks really good. The one issue I see is that I don't see any calculations on your page. I am assuming that you have just not added them yet.
Advise to Hunter Joyner:
Your decision matrix and reasoning looks well thought out and well done, however, it appears the rest of your site is not up to date and the image boxes are blank. I am assuming you are still working on your assignment.