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Team CNH

Final Presentation. Team CNH. Raquel Ciappi Brad Miller Stephen Petfield Chris Uthgenannt. Background Information. Case New Holland (CNH) is the number one manufacturer of agricultural tractors and combines Products include: Harvesting and seeding equipment Balers

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Team CNH

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  1. Final Presentation Team CNH Raquel Ciappi Brad Miller Stephen Petfield Chris Uthgenannt

  2. Background Information • Case New Holland (CNH) is the number one manufacturer of agricultural tractors and combines • Products include: • Harvesting and seeding equipment • Balers • Disc mowers and mower conditioners

  3. Disc Mowers • Disc mowers are used to cut crops such as alfalfa and hay before baling • Mowers utilize 4-6 oppositely rotating blade heads aligned along a shaft underneath the mower’s hood • Under normal operating speeds blade heads rotate at 3000 rpm • A protective curtain on the mower is used to provide shielding from high-speed projectiles • Conditioning rolls are used to crush crop stems and decrease drying time

  4. Problem Definition • Before cutting, crops must pass by the protective curtain • Current curtain exerts a large force on crops causing a knockdown effect and lower quality cut • To eliminate this effect farmers are mowing with the mower deck in a raised position • Raised deck poses safety hazards from high speed projectiles

  5. Project Scope • Identify causes of knockdown force (KDF) • Create testing methods to quantify knockdown force • Design a new shielding system to attenuate knockdown force while maintaining adequate projectile protection

  6. Wants and Metrics • Using discussions with CNH a set of wants was developed • Metrics were created as a basis for design evaluation

  7. Design Proposal • Possible areas for modification of existing design to decrease knockdown: • Turbulent airflow underneath mower • Curtain material • Mounting system • Each factor is assessed using engineering analysis and conducting tests in a controlled environment • Key findings implemented in a new design prototype

  8. Proposed Modifications • Employ air vents and mesh curtain to control turbulent airflow generated by mower • Implement lighter curtain material • Modify mounting configuration for hinge system

  9. Airflow Analysis • Preliminary airflow analysis was conducted to examine turbulent airflow effects on curtain • Mower curtain modeled as a flat plate subjected to normal flow • Drag effects exert significant outward force on mower curtain (22.3 lbf) • Further experimental testing needed to fully understand airflow effects

  10. Airflow Testing • Initial testing examined airflow effects by measuring airflow velocities using an anemometer • Measurements taken at 10 different locations along lower and upper halves of curtain • 2 sets of trials conducted: • Closed deck hood • Open deck hood

  11. 1 2 3 4 5 6 7 8 9 10 Preliminary Results • Similar patterns seen for each testing configuration • Air velocities projected outward suggest use of mesh at high velocity locations

  12. Airflow KDF Contribution • Conduct testing measuring the force needed to deflect curtain • Measurements taken with mower on and off • Measurements at 4 locations along curtain • Examines the role of airflow with respect to knockdown force • Results show airflow is a significant factor in causing crop knockdown

  13. Mower Deck Ventilation • Another method to control airflow is implementation of vents on the mower deck • Examining blade head air direction, vents installed at optimal locations on mower deck • To evaluate vent effectiveness air velocities were measured at: • Bottom of curtain • Each vent location • Different vent configurations employed to examine variations in air velocity

  14. 5 4 3 2 1 Ventilation Test Results • Results suggest that no vent combination reduces air velocity • Velocities at bottom of curtain actually increased with vents

  15. CFD Analysis • Computational Fluid Dynamics (CFD) performed • Confirms testing results and further explores turbulent air patterns • Simple simulation in COSMOS Flow Works • CFD results show little or no velocity near deck hood • Highest velocities point directly towards curtain

  16. Airflow Conclusions • Airflow is a significant factor in crop knockdown • Testing and CFD results demonstrate that vents do not control airflow • Modifying turbulent air effects of mower is complex and not feasible • Employing mesh curtain sections still a viable method to reduce knockdown force

  17. Proposed Material Design • Curtain design consists of a non-homogenous solid material lighter than existing design • Sections of mesh material employed at areas with high air velocities • Conduct testing to: • Ensure mesh passes ISO safety standards • Select a material to lower knockdown force

  18. Etch Test • Modified ISO standards test to determine projectile ejection patterns • Mower curtain replaced by layers of plywood, Styrofoam, and paper • Mower pulled by tractor over piles of sand, gravel, and water mixture • Projectile ejections recorded by indentations or projectiles lodged in Styrofoam Mower deck Plywood Sand and gravel Styrofoam Mower blades Paper

  19. Etch Test Results • Styrofoam divided into 6 sections • Projectile impacts were counted and separated into large and small categories • Large projectiles averaged 28 strikes per section • Indicates that solid curtain material must be used PICTURE OF STYROFOAM GOES HERE!

  20. Transition! • Add some kind of slide so that we can transition from material to mounting without losing the audience because we haven’t discussed a way to evaluate the knockdown force of different materials

  21. Mounting Method • Three new mounting methods proposed: • Conventional hinge • Spring hinge • Counterweight hinge • Preliminary analysis of each hinge design was conducted to predict each system’s performance

  22. Mounting Analysis • Assuming no curtain deflection, equations were derived for each mounting system • Illustrate behavior of knockdown force with varying angle (taken from horizontal) Basic Hinge Spring Hinge Counterweight

  23. Mounting Analysis Results • Derived equations were used with approximate values for each parameter • Force vs. Angle graph constructed to compare designs • Predicts performance of each mounting configuration • Spring hinge and counterweight most appealing designs • Minimizing both force and angle will produce best results

  24. Component Integration • The optimal curtain material and mount need to be determined • Testing apparatus designed to quantify knockdown force of various materials and configurations under controlled conditions • Eliminates turbulent air flow variable • Knockdown Force Test (KDF Test)

  25. Motor Crossbar Load Cell Knockdown Force Test • Apparatus utilizes load cell to measure force exerted by moving curtain assembly • Electric motor provides constant curtain speed of 0.642 mph • 12 trials performed to assess forces of 4 different materials and 4 mounting systems

  26. KDF Test Results • Lighter materials reduce knockdown force • Test results similar to hand calculations • Hinge designs serve to attenuate knockdown • Vinyl and Polyurethane materials were too light for spring hinge and counterweight

  27. Material Conclusions • Vinyl and Polyurethane materials performed best but are not used • Materials cannot withstand turbulent airflow generated by mower • Single-ply curtain used on final design • INSERT VIDEO OF VINYL CURTAIN FLAPPING

  28. Mounting Conclusions • Existing fixed mount produced largest knockdown force • Counterweight ideal but not used for final design • More complex design • Requires more parts • Longer installation times • Implement conventional hinge design

  29. Prototype Design • Add stuff here

  30. Design Validation • Compare prototype design to original system using: • Validation testing • Design metrics and target values: • Safety • Knockdown Force • Compatibility • Simplicity • Production Cost

  31. Validation Testing • Curtain assembly performance test evaluates new design • Full scale validation test • Measured the force of 2” inward curtain deflection with mower on and off • Force measurements recorded for: • Hinged single-ply • Fixed single-ply • Fixed double-ply

  32. Curtain Assembly Performance Test Results • Hinged single-ply yielded lowest force values • Confirm key findings of KDF test • Validates final design

  33. Design Metrics Evaluation • New design uses material which passes ISO safety tests • Reduction in knockdown force by .4559 lbf • Compatible and simple design • Small increase in production cost per unit

  34. Final Design? • Final design slightly modified to reduce manufacturing costs

  35. Production Cost

  36. Total Project Cost *=not actually purchased by team

  37. Path Foward

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