Final Presentation

Raquel CiappiBrad MillerStephen PetfieldChris Uthgenannt

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 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

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

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

Using discussions with CNH a set of wants was developed

Metrics were created as a basis for design evaluation

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

Employ air vents and mesh curtain to control turbulent airflow generated by mower

Implement lighter curtain material Modify mounting configuration for hinge

system

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

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

Similar patterns seen for each testing configuration

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

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Airflow Measurements: No curtain, Raised Deck

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Bottom Portion

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Airflow Measurements: No curtain, Lowered Deck

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Bottom Portion

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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

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

Results suggest that no vent combination reduces air velocity

Velocities at bottom of curtain actually increased with vents

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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 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

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

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

Plywood

Styrofoam

Paper

Mower deck

Sand and gravel

Mower blades

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!

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

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

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

Derived equations wereused with approximatevalues for each parameter

Force vs. Angle graphconstructed to comparedesigns

Predicts performance ofeach mounting configuration

Spring hinge and counterweight most appealing designs

Minimizing both force and angle will produce best results

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 variableKnockdown Force Test (KDF 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

Motor

Load Cell

Crossbar

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

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

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

Add stuff here

Compare prototype design to original system using: Validation testing Design metrics and target values:

▪ Safety▪ Knockdown Force▪ Compatibility▪ Simplicity▪ Production Cost

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

Hinged single-ply yielded lowest force values Confirm key findings of KDF test Validates final design

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 slightly modified to reduce manufacturing costs

Item Cost Quantity Total Cost

Hinges $1.50 6 $9.00

Curtain $23.40 1 $23.40

Hardware $.05/piece 12 $0.60

Assembly$.50/fastener 6 $3.00

$1.00/weld 6 $6.00

Total $42.00

Item Cost

Steel $100.00

Aluminum $40.00

Curtain Materials $132.08

Hinges $41.58

KDF Motor $57.44

Etch Test Supplies $81.26

Hardware $50.00

Misc. Items $105.53

Lab VIEW Data Acquisition Program*

$4000.00

Load Cell* $300.00

Machine Shop Labor $850.00

Labor $6375.00

Total Project Cost $12,132.89

*=not actually purchased by team