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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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Final presentation

Final Presentation

Team CNH

Raquel Ciappi

Brad Miller

Stephen Petfield

Chris Uthgenannt


Background information

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


Disc mowers

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


Problem definition

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


Project scope

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


Wants and metrics

Wants and Metrics

  • Using discussions with CNH a set of wants was developed

  • Metrics were created as a basis for design evaluation


Design proposal

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


Proposed modifications

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


Airflow analysis

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


Airflow testing

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


Preliminary results

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3

4

5

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10

Preliminary Results

  • Similar patterns seen for each testing configuration

  • Air velocities projected outward suggest use of mesh at high velocity locations


Airflow kdf contribution

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


Mower deck ventilation

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


Ventilation test results

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Ventilation Test Results

  • Results suggest that no vent combination reduces air velocity

  • Velocities at bottom of curtain actually increased with vents


Cfd analysis

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


Airflow conclusions

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


Proposed material design

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


Etch test

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


Etch test results

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!


Transition

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


Mounting method

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


Mounting analysis

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


Mounting analysis results

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


Component integration

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)


Knockdown force test

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


Kdf test results

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


Material conclusions

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


Mounting conclusions

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


Prototype design

Prototype Design

  • Add stuff here


Design validation

Design Validation

  • Compare prototype design to original system using:

    • Validation testing

    • Design metrics and target values:

      • Safety

      • Knockdown Force

      • Compatibility

      • Simplicity

      • Production Cost


Validation testing

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


Curtain assembly performance test results

Curtain Assembly Performance Test Results

  • Hinged single-ply yielded lowest force values

  • Confirm key findings of KDF test

  • Validates final design


Design metrics evaluation

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


Final design

Final Design?

  • Final design slightly modified to reduce manufacturing costs


Production cost

Production Cost


Total project cost

Total Project Cost

*=not actually purchased by team


Path foward

Path Foward


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