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Assignment Five- Base
Solid Model of Component
Base Model
FRDPARRC
FRDPARRC
Calculations
Material Selection
Materials
From the above calculations we find that the maximum normal stress allowed before failure is 5.13 ksi and the maximum shear
stress allowed before failure is 2.35 ksi. Some of the materials that fit the description are down below. Other factors that I took into account when making the decision are the density of the material,
and the average cost of the material
* Density is a good factor to recognize because it will determine the weight of the component. The stress of elements depend on the elements
above them in this module, with the shaft and transmission gear supporting almost all of the pressure of the moment caused by the water coming from the hose
plus the weight of the previous elements. This means that a lighter material is more valuable to this design because it will put less stress on the gear.
* Cost is another important factor because in the real world, the material must be purchase in order to make the design. The cost of the material plays a huge
part in the cost of the product. The more expensive the material is per cubic inch, the higher the price of the product would be in order to make a profit in
the material.
* The properties of the material are not as important to the design of the base as they are for other components, since it will not have extra stresses other than the tension in the hose and the force of the water coming out of the valve.
*Assumption: The cost of an alloy (like SAE Steel 1025) is about the cost of the base material to make
the material. This is not a bad assumption, since the cost of the actual material will be more than the base
material*
| Material |
Max Normal Stress (ksi) |
Max Shear Stress (ksi) |
Yield Strength |
Density (lb/in^3) |
Cost of Material ($/lb) |
Resources |
| Aluminum (Cold-Worked Wrought) 1060 H14 |
around 14 ksi |
at least 9 ksi |
About 13 ksi |
0.0975 |
$0.89 |
*Machinery's Handbook, pg. 501 and pg. 527; *http://www.infomine.com/investment/metal-prices/aluminum/ (Cost) |
SAE Steel 1025 |
around 60 ksi |
around 45 ksi |
About 45 ksi |
0.2839 |
$0.36 |
*Machinery's Handbook, pg. 501 and pg. 527; *http://www.infomine.com/investment/metal-prices/aluminum/ (Cost) |
| Titanium |
around 50 ksi |
Not Listed |
40 ksi |
0.163 |
$2.27 |
*Machinery's Handbook, pg. 501 and pg. 527; *http://www.infomine.com/investment/metal-prices/titanium/ (Cost) |
| Tin Bronze |
21 ksi |
23 ksi |
15 ksi |
0.306 |
$1.42 |
*Machinery's Handbook, pg. 501 and pg. 527; *Scrap Monster |
Doing analysis on each of the four materials, I choose the tool steel for the part. Even though the SAE tool
steel has a higher density, the small size of the part means that the extra weight will not make a huge difference.
The steel is also very easy to turn, and leaves only a small amount of mess. The steel is hard enough that it can allow for threads without
breaking. Finally, the steel has a lower cost/lb, which means that the material I will get is lower in cost overall.
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