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

Team 8: Plasticity Model Zachary Morrison, Dillon Edlund Laken Yargus, Stephanie Yazzie 1

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 2

Functional Decomposition Black Box Model Laken Yargus 3

Functional Decomposition Zach Morrison 4

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. Dillon Edlund 5

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 Laken Yargus 6

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. ● Stephanie Yazzie 7

Analysis: Displacement Sensors Rotating Potentiometer Linear Potentiometer Contact Sensors (Variable Resistors) [2] ● Potential for high accuracy ○ Small and simple design ○ Sliding Potentiometer Easy to program ○ Manufactured sliding and linear ● potentiometers - small displacements Rotating potentiometer - manufacturing ● of pulley and spring system Custom wire variable resistor ● Large displacements ○ Compact design ○ Calculations showed wire resistance of ○ 4525 ohm/ft for 1/8in accuracy Zach Morrison 8

Analysis: Displacement Sensors Rotating Potentiometer Linear Potentiometer Contact Sensors (Variable Resistors) [2] ● Potential for high accuracy ○ Small and simple design ○ Sliding Potentiometer Easy to program ○ Manufactured sliding and linear ● potentiometers - small displacements Rotating potentiometer - manufacturing ● of pulley and spring system Ultrasonic Sensor Custom wire variable resistor ● Large displacements ○ Compact ● Compact design ○ Satisfactory resolution ● Calculations showed wire resistance of ○ 4525 ohm/ft for 1/8in accuracy Zach Morrison 9

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. Dillon Edlund 10

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 ● Dillon Edlund 11

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 ● Dillon Edlund 12

Gantt Chart Stephanie Yazzie 13

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 ○ Stephanie Yazzie 14

Questions? 15

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]. 16

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