Spindle Shaft
From Teamnumber1
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* Altered [http://web.mit.edu/mmcbrien/Public/2-72/Spindle/shaft_stress_slope_fatigue.m matlab tool] to take into account fatigue at bearing A. | * Altered [http://web.mit.edu/mmcbrien/Public/2-72/Spindle/shaft_stress_slope_fatigue.m matlab tool] to take into account fatigue at bearing A. | ||
* For a steel shaft, we have a slope factor of safety of 9, a stress factor of safety of 15. The stresses are an order of magnitude below the endurance limit, so fatigue should not occur anywhere in this shaft. (or, a lifetime of 10^10 minutes - about right according to Chris). | * For a steel shaft, we have a slope factor of safety of 9, a stress factor of safety of 15. The stresses are an order of magnitude below the endurance limit, so fatigue should not occur anywhere in this shaft. (or, a lifetime of 10^10 minutes - about right according to Chris). | ||
| - | * Assumptions - w_shaft = 570rpm, axial force = 100N, radial force = 240N, stress concentration at fillet = 2.5. | + | * Assumptions - w_shaft = 570rpm, axial force = 100N, radial force = 240N, stress concentration at fillet = 2.5, assume 1020 steel which is pretty weak. |
| + | * Endurance limit of 1020 steel = 210MPa, k_overall=0.75, Von Mises stress at Bearing A = 21.6MPa, and smaller at nut by rough calculation. | ||
Revision as of 21:09, 12 April 2007
Spindle Shaft Design, 7th April
- Developed a model to predict the peak cutting force and shaft torque
- Wrote a matlab tool (edited version below) to determine peak forces and bending moments in spindle shaft and bearings
- Wrote a matlab tool to specify bearing from cutting force, torque, and desired life and reliability (via the Weibull Equation)
- Specified a collet from sheets provided in lab
- Used results from above tools and supplied lathe solid model to specify shaft dimensions:
- 30 mm shaft outer diameter, 50mm diameter for center section
- 10 mm inner diameter
Spindle Shaft Design, 12th April
- Altered matlab tool to take into account fatigue at bearing A.
- For a steel shaft, we have a slope factor of safety of 9, a stress factor of safety of 15. The stresses are an order of magnitude below the endurance limit, so fatigue should not occur anywhere in this shaft. (or, a lifetime of 10^10 minutes - about right according to Chris).
- Assumptions - w_shaft = 570rpm, axial force = 100N, radial force = 240N, stress concentration at fillet = 2.5, assume 1020 steel which is pretty weak.
- Endurance limit of 1020 steel = 210MPa, k_overall=0.75, Von Mises stress at Bearing A = 21.6MPa, and smaller at nut by rough calculation.
