IX. (Intermediate) torsion

IX. (Intermediate) torsion

Background and context for the work of the sub-team

• Loading from bogie causes a net torque
• Guideway must be analyzed under torsional loading
• Two methods being used: Theoretical modeling (hand calculation/ANSYS) and physical experimentation

Description of the Sub-team and Objectives

• Purpose: to analyze to analyze precision of ANSYS model by comparing model’s behavior to physical specimen
• First objective: To calibrate actual torsion testing
• The torsion testing machine was made in the ‘40s and had not been used since 08
• Stock pieces of steel used for calibration purposes

Design Requirements and Specifications for the Sub-team’ s Work Products

• Calibration Design Requirement

i. Test two circular cross sectional tubes to calibrate the torsion machine

1. The specimens must fit in the torsion tester (between the two chucks)
2. The specimens must give an angle of twist significant enough to accurately measure and compare to hand-calculations.  This is relative to the machine’ s loading capacity

• Strain Specimen Design Requirement (Intermediate Specimens)

i. Test one circular cross section with a strain gauge applied to it and compare results to ANSYS and hand calculations

1. Strain must be significant enough to measure and to compare to ANSYS results

ii. Test one square cross section for angle of twist and with strain gauge applied to it. Compare results to ANSYS and hand calculations

1. The specimen must be modified to fit in the torsion tester, since the chucks are triangular
2. The torque needs to be distributed evenly along the center of the pipe

• Track design requirements

i. Test a scaled down track, measuring strain for comparison to an ANSYS model

1. The specimen must fit within the length and width constraints of the torsion machine
2. Strain gauges should be placed at multiple locations on the track
3. The strain and angle of twist must be significant enough to accurately measure

State-of- the-Art/Literature Review for the Sub-team’ s Sphere of Work

• Other guideway systems were studied
• London Heathrow airport analyzed
• Siemens People Mover H-Bahn in Dortmund, Germany also analyzed
• Skytran by NASA also analyzed

Description of Your Design

• Team started torque twist measurements with 0 N and incremented in 750 lb steps until 8250 lbs
• Intermediate specimens were later analyzed
• Scaled guideway design

i. Initial design created by Bengt Gustafsson

Analysis/Validation/Testing

• Calibration specimens

i. Calibration specimens had significant error

• System was low accuracy due to old machine
• Strain behavior more accurately predicted in ANSYS then the circular pipe
• Percent error started became lower with increased torque

Money spent on your project

• Due to most materials being donated, only $28.00in total was spent

Results and discussion

• ANSYS for stress analysis on superway guideway is justified, but safety factors should be taken into account for error
• Strain deviations between physical/theoretical specimens tend to become less as torque becomes higher
• Physical specimen has imperfect geometries that could lead to extra error
• A factor of 1.5 is recommended to be applied to ANSYS strain analysis

Conclusions and Suggestions for Future Work

• Team did not meet all design requirements set out in fall due to time constraints and dependencies
• Communication with dependencies of vital importance
• Work around schedules of other people instead of waiting for results