K tec 1243 tail load development-fatigue-optimization nafems 2016
- 1. 1243 ADT Scraper Tail Validation Project Cynde Murphy/Wayne Tanner Adaptive Corp. June 2016
- 2. K-Tec History • K-Tec started in 2000, when Ken Remple built his first pull-type scraper in his barn, due to frustration with lack of quality pull-type scrapers on the market • Today the manufacture over 100 vehicles per year • Sizes range from 25 to 63 yard capacity
- 3. About Adaptive Corporation Connecting Virtual Design to the Physical World Innovate Refine Validate
- 4. Areas of Expertise PLM/CAD Quality/MetrologySimulation
- 5. 1243 ADT Scraper in Action…
- 6. 1243 ADT Design • New Concept to allow large design to assemble into shipping container • Design sized using max/worst case static loading • Final design approximately 20% over target weight
- 7. 1243 ADT Scraper To begin optimizing the vehicle, we need to understand … Time history loading of their system in operation Representative duty cycle of their system Fatigue life of their system (welded structure) Where they can optimally minimize weight and cost of their system Goal of 20%+ Weight Savings
- 8. 1243 ADT Scraper Tail C-Frame Bowl Tail
- 9. Project Goals: • Create FEM of Tail System • Determine Load Time Histories on System via Measured Data • Develop Duty Cycle from Load Time Histories • Calculate Fatigue Life based on Duty Cycle/Load Time Histories • Perform Optimization Based on Load Time Histories
- 10. Create FEM of Tail System
- 11. Create FEM of Tail System Apply Unit Loads (100 lb) at Loaded Interfaces Axle LH: FX,FY,FZ Low Pin: FX,FY,FZ Axle RH: FX, FY, FZ Push Block: FX, FY, FZ Strut LH Strut RH Eject Cyl: FX Hitch Pin: FX Top Pin: FX,FY,FZ FEA Unit Loads
- 12. The True-Load™ Workflow FEA Unit Loads Virtual Gauge Placement True-Load/Pre-Test Strain Measurement Loading from Strains True-Load/Post-Test
- 13. Linear Systems and Loads Loads DisplacementsStrains Are Proportional to In other words 𝐹 = 𝐾𝑥 and 𝜀𝐶 = 𝐹 F, Load vector K, Stiffness matrix 𝜖, Strain matrix C, Correlation Matrix Forces from strains 𝐹 = 𝜀𝐶 From Test From FEA
- 14. T-L Pre-test * identify strain gage placement based on FEA Unit Loads Virtual Gauge Placement True-Load/Pre- Test
- 15. Strain gage Data Collection… on various terrains, roads and duty cycles Strain Measurement
- 16. T-L Post-Test: • Calculate Loads from strain measurement Loading from Strains True-Load/Post-Test Unit Loads Event 2 Push Load with D8 Full
- 17. T-L Post-Test: • Unit Loads of Fully loaded system vs Weight on Rear Axle of Fully loaded system Loading from Strains True-Load/Post-Test Static Load (Full Pay Load) 70,641 lbs Load Wt Only (rear) Event 2 Push Load with D8 Full
- 18. T-L Post-Test Loading from Strains True-Load/Post-Test Total Vertical Load at Axle: 33420 lbs (~5.3% from Estimate Pay Load value of 35321 lbs) This also demonstrates that the FEM Unit Load can simulate the Fully Loaded condition Strain Gage Sim vs Measured Cross-Plot
- 19. T-L Post-Test Load Time History: Event 5: Haul across woops straight Loading from Strains True-Load/Post-Test
- 20. T-L Post-Test Load Time History: Event 11: Haul High Speed Empty on Rough Haul Road Loading from Strains True-Load/Post-Test
- 21. • Based on input from customer • 1 duty cycle = 1.07 hours of operation • Direct fe-safe interface Duty Cycle Development 1x 2x 4x 1x 2x 1x 1x 2x 1x 1x 1x 1x
- 22. Fatigue Life CalculationsDatasets = Unit Load ABAQUS Results file (*.odb) Fatigue Loading = Repeats of Events in Duty Cycle (*.ldf) • 1 Elastic block per road event (there are 12) • Duty Cycle: Each elastic block/road event is repeated accordingly to create Duty Cycle Each block includes datasets (unit loads) from 19 unit loads Each block Datasets (unit loads*) are scaled according to T-L *Unit Time Histories Entire Duty Cycle= 1.1 hours of operation 1x 2x 4x 1x 2x 1x 1x 2x 1x 1x 1x 1x
- 24. Fatigue Life CalculationsVerity and A36 Parent Material • Weld geometry was defined in FEM at critical locations • Verity welds defined within fe-safe for fatigue calculations • Remaining structure defined with A36 fatigue properties
- 25. Fatigue Life Calculations Identify Low Life Welds
- 26. Next Step…Optimization Load Cases: Highest strain amplitudes in rear of structure Unit loads (static points) – snapshots in time history Optimization Topology Region
- 27. Optimization Loads Event 2: Push Load with D8 Full, t=235.52s Loadx100(lbs)
- 28. Optimization Loads Event 5: Haul Across Woops Straight, t=133.438s Loadx100(lbs)
- 29. Optimization Loads Event 6: Haul Across Alternating Woops, t=82.794 Loadx100(lbs)
- 30. Optimization Criteria Design Envelope created • Interface to applied load must remain • Interface to rest of Tail structure must remain Objective – maximize stiffness Constraints – design region volume remaining <= 40% Geometry conditions • left/right planar symmetry • 2 halves with casting pull direction pull away from middle (prevent vertical wall in middle of structure)
- 32. Roller Optimization • 36% Weight Reduction in rear roller • Confidence in optimization due to accurate load measurements CAD weight: 272 lbs CAD weight: 428 lbs
- 33. Questions?