For a Mechanical Design class project, the goal was to improve the strength-to-weight of a hook assembly under three load cases to produce highest metric compared against peers’ designs.
Design Constraints
- Additive/subtractive geometry changes only.
- Material: S/Steel_PH15-5 (NX Material Library) (145ksi yield)
- Fixed constraint SPC123456 on base
- Originally across the full flat base
- Modified to apply to four 0.5” radius stress risers under bolts
- 1900lbf preload applied over bolt surfaces
- Load cases:
- 1250 lbf horizontally in +X direction
- 1875 lbf at 45° below horizontal
- 2500 lbf vertically in -Z direction
Base Case
- Base Case:
- Worst-case metric used for load case testing
- Initial strength-to-weight (SW) = 816.3794
Base Case Finite Element Model
Base Case Finite Element Analysis (Linear Statics)
Design Strategy & Improvements
- Low stress region material removal prioritized to reduce material waste
- Base of hook
- Sides of arm
- High stress region material addition to reinforce weak points
- Wider blends on back face of arm/hook
- Results
- 138% strength-to-weight improvement
- SW = 1126.24
- Validated with <5% convergence study
Optimized Finite Element Model
Optimized Finite Element Analysis (Linear Statics)
