Team 8: Plasticity Model Zachary Morrison, Dillon Edlund Laken - - PowerPoint PPT Presentation

Team 8: Plasticity Model

Zachary Morrison, Dillon Edlund Laken Yargus, Stephanie Yazzie

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Project Description

• Client: Dr. Heidi Feigenbaum
• ME 561 Engineering Plasticity
• Student will “Use physical models to describe plasticity behavior of

materials in 2D (LO1.1, 1.3)”

• Plasticity theory describes a materials behavior beyond the elastic
• limit. Behavior can be modeled using friction and springs. Stress

and strain relates to force and displacement.

• Does not perfectly model plasticity
• Purely educational, helps students to visualize plasticity

Zach Morrison

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Functional Decomposition

Black Box Model

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Laken Yargus

Functional Decomposition

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Zach Morrison

Design Description

• The original model has been reduced

to measure only tension force and displacement in 1 dimension for prototyping purposes.

• Will help with proof of concept.
• Scalable to 2 dimensions for final

design

• Strain gauge (if used) will be attached

between the handle and front spring, and connected to Raspberry Pi.

• Displacement will be measured by

mounted ultrasonic range sensor.

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Dillon Edlund

Analysis: Frictional Surfaces

Rubber on glass-like material

• Fs = µs x N

Fk = µk x N

• N = 3 lb
• µs = µk = 2.0
• Fs = Fk = 6 lbs

Measured values of W1322 Anti-Vibration rubber on glass-like material 45 lb neodymium magnet on steel

• 10% - 20% of pull force [3]
• Shear almost wholly dependant on friction and air gap [4]

Next test will be 65 lb and 45 lb magnets on smooth polished steel

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Laken Yargus

Analysis: Springs

• Assumptions: Force (F), Spring material (Oil-tempered wire), Shear

modulus (G), wire diameter (d), outer diameter (OD), mean diameter (D = OD - d), number of coils (na)

• Equations:
• k = F/x
• k = (G*d^4) / (8*d^2*na)
• Spring displacement:

x = 5.67 in.

• Spring constant:

k = 0.8812 lb/in.

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Stephanie Yazzie

Analysis: Displacement Sensors

• Contact Sensors (Variable Resistors) [2]

○ Potential for high accuracy ○ Small and simple design ○ Easy to program

• Manufactured sliding and linear

potentiometers - small displacements

• Rotating potentiometer - manufacturing
• f pulley and spring system
• Custom wire variable resistor

○ Large displacements ○ Compact design ○ Calculations showed wire resistance of 4525 ohm/ft for 1/8in accuracy

Rotating Potentiometer Linear Potentiometer Sliding Potentiometer

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Zach Morrison

Analysis: Displacement Sensors

• Contact Sensors (Variable Resistors) [2]

○ Potential for high accuracy ○ Small and simple design ○ Easy to program

• Manufactured sliding and linear

potentiometers - small displacements

• Rotating potentiometer - manufacturing
• f pulley and spring system
• Custom wire variable resistor

○ Large displacements ○ Compact design ○ Calculations showed wire resistance of 4525 ohm/ft for 1/8in accuracy

Rotating Potentiometer Linear Potentiometer Sliding Potentiometer Ultrasonic Sensor

• Compact
• Satisfactory resolution

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Zach Morrison

Analysis: Raspberry Pi DAQ System

• Script written in Python running on

Raspbian

• Code will read sensor data and save it to a

CSV file

• CSV file will be updated every second with

new input data

• Concurrent code will call CSV file and plot

the data in real time using Matplotlib.

• Multiple sensors can be read and data

saved.

• Code will be made executable for ease of

use.

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Dillon Edlund

Customer Requirements

• Capable of recreating general force versus displacement graphs
• Springs capable of compression and tension
• Reliable data collection (force and displacement)
• Easy to move from office to classroom (ergonomic)
• Ease of operation (can be operated by students with little-to-no training)
• Safety (Low risk of injury with hands-on use)
• Standalone display

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Dillon Edlund

Customer Requirements

• Capable of recreating general force versus displacement graphs

1D

• Springs capable of compression and tension Only tension (1st semester only)
• Reliable data collection (force and displacement)
• Easy to move from office to classroom (ergonomic)
• Ease of operation (can be operated by students with little-to-no training)
• Safety (Low risk of injury with hands-on use)
• Standalone display

User provided display

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Dillon Edlund

Gantt Chart

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Stephanie Yazzie

Budget

• Total Available:

○ $400.00

• Actual expenses to date:

○ Analog to Digital Conversion Chip, $15.75 ○ Raspberry Pi & Kit, $119.99 ○ Rubber Surface, $15.74 ○ Magnets, $12.99

• Resulting balance:

○ $235.54

• Anticipated remaining expenses:

○ 2 Extension springs, $20.00 ○ Track system, $25.00 ○ Structure - Plywood, $10.00

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Stephanie Yazzie

Questions?

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References

[1] Budynas, R. and Nisbett, J. (2008).Shigley's mechanical engineering design. 9th ed. Boston: McGraw-Hill Higher education, pp.518-560 [2] Omron. (2007). Displacement Sensors / Measurement Sensors. Retrieved March 26, 2019, from http://www.ia.omron.com/support/guide/56/introduction.html [3] W. GmbH, “Why does my magnet not carry the maximum weight on the wall?,”

• supermagnete. [Online]. Available:

https://www.supermagnete.de/eng/faq/Why-does-my-magnet-not-carry-the-maximum- weight-on-the-wall. [Accessed: 07-Apr-2019]. [4] M. Corporation, “Terminology,” Magnetech Corporation. [Online]. Available: http://www.magnetechcorp.com/terminology.html. [Accessed: 07-Apr-2019].

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Appendix

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Appendix

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