lec TC strain gauge

Information about lec TC strain gauge

Published on February 16, 2008

Author: Mentor

Source: authorstream.com

Content

Introduction to Thermocouple and Strain Gauge:  Introduction to Thermocouple and Strain Gauge Dr. Chi-fu Wu ME 4903-Special Problem in ME Reference: www.omega.com, www.vishay.com, zone.ni.com GTREP, Savannah Oct. 21, 2004 Outline:  Outline How to measure temperature? What is thermocouple? How to select thermocouple? What is strain? What is strain gauge? How to select and install strain gauge? How to measure strain using strain gauge? How to Measure Temperature?:  How to Measure Temperature? What is temperature? What effects may temperature cause on material or structure? Examples: Resistance Volume Emf (Electromotive Force, Thomas Seebeck effect 1821 from the joint of two dissimilar metals) Thermal radiation (astronomy, the temperature of a star) Appearance (color) Existing sensors: RTD (Resistance Temperature Device), thermistor Thermometer (thermal expansion device, use mercury or organic fluid or bimetallic device) Thermocouple Infrared radiator Liquid crystal (change of state device) Comparison of Temperature Sensors:  Comparison of Temperature Sensors What is Thermocouple?:  What is Thermocouple? What problems do occur when we connect the thermocouple to a voltmeter or make wire extension ? Answer: cold junction compensation from software correction. ( is the Seebeck coefficient for small delta T) Temperature Conversion Table (I):  Temperature Conversion Table (I) The type of thermocouple is associated with the type of metal joints. Constanan is a generic name of copper-nickel alloy. Its composition is not the same when used in types E, J and T. Temperature Conversion Table (II):  Temperature Conversion Table (II) Hand-held portable thermocouple readout has done this voltage- temperature conversion in the circuit for users. Have to match the right type of thermocouple specified in the readout. How to Select Thermocouple?:  How to Select Thermocouple? Junction protection: sheath or not. Tip size: big or small Thermocouple type (T, J, K, E, S, R): Temperature range (cryogenic or high temperature) Corrosion (noble metal is more inert to chemical attack) Termination: wire or connector Cost How to Use Thermocouple (TC)? :  How to Use Thermocouple (TC)? The tip of TC should be buried inside the material and gets to the test point as close as possible. Use thermally conductive epoxy or thermal interface material to mount TC. The extension cord should match the type of TC. Otherwise, additional Emf errors would be produced at junctions. To reduce the noise, the TC wires can be wrapped with aluminum foil as a EMI shield. To calibrate any signal drifting, use fixed points such as water boiling point (100°C at 1atm) and ice melting point (0 °C at 1atm) for calibration. What is Strain?:  What is Strain? Strain is the amount of deformation of a body due to an applied force. More specifically, strain (e) is defined as the fractional change in length. What is Strain Gauge? :  What is Strain Gauge? A strain gauge, a device whose electrical resistance varies in proportion to the amount of strain in the device. The most widely used gauge is the bonded metallic strain gauge. How to Select Strain Gauge? Use Vishay Strain Gauge as Example:  How to Select Strain Gauge? Use Vishay Strain Gauge as Example Grid length (250 = 0.250 inch) Grid pattern and tab geometry (uniaxial, biaxial, three-element rosette, shear pattern) Type of grid alloy and backing (strain gauge series EA, Constantan grid, polyimide backing) Option features: protection, termination (L = pre-attached Leads, E= Encapsulated with exposed tabs.) Strain gauge resistance (350=350 ohms) Self temperature compensation (STC # = 06 for steel substrate) http://www.vishay.com/brands/measurements_group/strain_gages/mm.htm Note : The S-T-C number is the approximate thermal expansion coefficient in ppm/ deg F of the structural material on which the strain gage will display minimum thermal output. How to Measure from Strain Gauge? :  How to Measure from Strain Gauge? Wheatstone bridge with strain gauge R3 When Vo is zero, R1*R3=R2*R4 When the strain gauge is strained, R3=R3+R Vo=   C / I E =   , where C = t/2, C is the distance to the neutral axis. M is the bending moment = PL I is the moment inertia for a cross section, I= b(t^3)/2 G = gauge factor, (R/R)/(L/L) The gauge factor for various alloys, A = 2.05, K = 2.1, D = 3.2, P = 2.0 (Vishay strain gauge) How to Install Strain Gauge? :  How to Install Strain Gauge? Objective Have strain gauge to produce the same amount of strain as the substrate. Procedure Align the grid direction with the uniaxial Solder wires to termination which provides stress relief. Apply adhesive to substrate and attach strain gauge with clamps and rubber pressure pads. Cure the adhesive at room temperature or elevated temperature. What happens to our plastic substrate when cure at elevated temperature? Tape or secure wires to avoid stress from heavy instrument. Where to Install TC and SG to WTC Model? (I):  Define the damage zone. Identify the failure mode: truss or bracket Determine strains and temperatures of trusses and brackets. Structure of World Trade Center WTC Model (12” x12”x 24”) Floor plane Where to Install TC and SG to WTC Model? (I) Where to Install TC and SG to WTC Model? (II):  Where to Install TC and SG to WTC Model? (II) If the truss (floor) fails and causes the model to collapse, where should the maximum deformation be ? If the bracket fails and causes the model to collapse, where should the maximum deformation be? Remember that the accuracy of strain gauge is affected by temperature. How to minimize heating effect on strain gauges? Backing with aluminum foil Tiles (weight) Heat Data Acquisition System-NI ELVIS National Instrument Inc., Educational Laboratory Virtual Instrumentation Suite:  Data Acquisition System-NI ELVIS National Instrument Inc., Educational Laboratory Virtual Instrumentation Suite Tasks: Follow the example document to construct the half bridge circuit for strain gauge. Tests existing NI VI programs for temperature and strain single-channel measurement. Integrate VI programs for simultaneous temperature and strain multi-channel measurements. Contact the lab manager Clint Jones at 912-966-7932 Resources: http://www.vernier.com/labview/ http://www.vernier.com/labview/nielvis.html http://www.ni.com/academic/companion_products_vernier.htm http://www.ni.com/pdf/datasheet/us/vernierflyer.pdf http://www.vernier.com/accessories/access.html?bta-elv&btd-elv&template=basic.html&title=Proto%20Board%20Connectors Safety Issues in WTC Model Testing:  Safety Issues in WTC Model Testing Potential Safety Issues: Fire caused by overheating Toxic fume from melting plastics Short circuit Pre-caution: Stop heating right after the WTC model starts to collapse Break the circuit by using a switch right to stop heating Keep a good ventilation by running the exhaust blower or conduct the test outside the building. Wear safety goggle, glasses and heavy glove when handle the heated model. Do not conduct testing without supervision.

Related presentations


Other presentations created by Mentor

Johari Window
30. 10. 2007
0 views

Johari Window

ConsolServiceCorp
28. 04. 2008
0 views

ConsolServiceCorp

astwood
22. 04. 2008
0 views

astwood

Eco24 16
17. 04. 2008
0 views

Eco24 16

wipo smes uln 07 www 89155
16. 04. 2008
0 views

wipo smes uln 07 www 89155

taiex ghymers rijen2006 ppt
14. 04. 2008
0 views

taiex ghymers rijen2006 ppt

e future
13. 04. 2008
0 views

e future

sapir 12 2007
10. 04. 2008
0 views

sapir 12 2007

cbm47 441
09. 04. 2008
0 views

cbm47 441

Ocean
07. 04. 2008
0 views

Ocean

Closing Plenary PERUGIA
30. 03. 2008
0 views

Closing Plenary PERUGIA

The Ming and Qing Dynasties
25. 03. 2008
0 views

The Ming and Qing Dynasties

fables and morals
14. 09. 2007
0 views

fables and morals

Temperate Woodland
14. 09. 2007
0 views

Temperate Woodland

OB IDDRI 200104
12. 10. 2007
0 views

OB IDDRI 200104

NacTem2007XuUszkoreit
15. 10. 2007
0 views

NacTem2007XuUszkoreit

Leduff course 1
16. 10. 2007
0 views

Leduff course 1

WIM
16. 10. 2007
0 views

WIM

Shakespeare Presentation
19. 10. 2007
0 views

Shakespeare Presentation

Puska
07. 09. 2007
0 views

Puska

Mystery Animal
14. 09. 2007
0 views

Mystery Animal

CREATION to EVOLUTION
14. 09. 2007
0 views

CREATION to EVOLUTION

nw pall care bad news
29. 09. 2007
0 views

nw pall care bad news

SUPPLY LCS MDS
22. 10. 2007
0 views

SUPPLY LCS MDS

PRESENTACION GTI Malaga
24. 10. 2007
0 views

PRESENTACION GTI Malaga

ethics health disparities
29. 10. 2007
0 views

ethics health disparities

halt
23. 10. 2007
0 views

halt

BTL Fuels
16. 11. 2007
0 views

BTL Fuels

2005 CeladrinLecture
17. 11. 2007
0 views

2005 CeladrinLecture

newsletters
05. 10. 2007
0 views

newsletters

Moscow Presentation
23. 11. 2007
0 views

Moscow Presentation

6 338 Progress Presentation
28. 12. 2007
0 views

6 338 Progress Presentation

6 01 T P Analog Systems
03. 01. 2008
0 views

6 01 T P Analog Systems

Prepare Yourself
04. 10. 2007
0 views

Prepare Yourself

idruspresentation
07. 01. 2008
0 views

idruspresentation

8p
24. 10. 2007
0 views

8p

stewart
08. 10. 2007
0 views

stewart

lizhitang
11. 10. 2007
0 views

lizhitang

Inter scholastic Sports
09. 07. 2007
0 views

Inter scholastic Sports

High School Athletics
09. 07. 2007
0 views

High School Athletics

4479
09. 07. 2007
0 views

4479

42 sp101
09. 07. 2007
0 views

42 sp101

2005 Flag Football Clinic
09. 07. 2007
0 views

2005 Flag Football Clinic

SNAP Propulsion
07. 11. 2007
0 views

SNAP Propulsion

Legend Powerpoint
28. 02. 2008
0 views

Legend Powerpoint

lect10
14. 09. 2007
0 views

lect10

bec
15. 10. 2007
0 views

bec

APS NW Poster
12. 03. 2008
0 views

APS NW Poster

UofWfAC06
10. 03. 2008
0 views

UofWfAC06

DrFlock
09. 07. 2007
0 views

DrFlock

health sports
09. 07. 2007
0 views

health sports

ASTR 2006 Presentation Template
29. 10. 2007
0 views

ASTR 2006 Presentation Template

4 DSM Design Guide
02. 01. 2008
0 views

4 DSM Design Guide

LiuhtoBaltic04
26. 10. 2007
0 views

LiuhtoBaltic04

STKU5 Larson
19. 06. 2007
0 views

STKU5 Larson

standard email
19. 06. 2007
0 views

standard email

Software Versions
19. 06. 2007
0 views

Software Versions

SDT Tech Briefing06 01 07
19. 06. 2007
0 views

SDT Tech Briefing06 01 07

SDT Tech Briefing
19. 06. 2007
0 views

SDT Tech Briefing

refresh cycle07
19. 06. 2007
0 views

refresh cycle07

Q2 FY07 Slides
19. 06. 2007
0 views

Q2 FY07 Slides

Q1 FY07 Slides
19. 06. 2007
0 views

Q1 FY07 Slides

psj 0 6 yukai e
19. 06. 2007
0 views

psj 0 6 yukai e

psj 06 schoenfeld e
19. 06. 2007
0 views

psj 06 schoenfeld e

PRI050 WH06
19. 06. 2007
0 views

PRI050 WH06

portal
19. 06. 2007
0 views

portal

usc csci 530 f06 l13
19. 06. 2007
0 views

usc csci 530 f06 l13

BOSC Markel
14. 09. 2007
0 views

BOSC Markel

PresentationBA avril06
23. 10. 2007
0 views

PresentationBA avril06

volvo 09
29. 02. 2008
0 views

volvo 09

qz qc mrt ridership
26. 03. 2008
0 views

qz qc mrt ridership

3a 3 Hellsten
14. 09. 2007
0 views

3a 3 Hellsten

1 IARU DoAST Presentation
09. 07. 2007
0 views

1 IARU DoAST Presentation

sicily03
19. 06. 2007
0 views

sicily03

norway
14. 12. 2007
0 views

norway

1999KC os tri
09. 07. 2007
0 views

1999KC os tri

Virgo Sigrav2004 SF
15. 11. 2007
0 views

Virgo Sigrav2004 SF

RICyT Innocom
25. 10. 2007
0 views

RICyT Innocom

Telekomunikacja Polska 1
14. 09. 2007
0 views

Telekomunikacja Polska 1

sas06 das
19. 06. 2007
0 views

sas06 das

parallel session 1
07. 09. 2007
0 views

parallel session 1

Kestrel PI Presentation
30. 10. 2007
0 views

Kestrel PI Presentation

Ch10rev 06
19. 02. 2008
0 views

Ch10rev 06

DemoStudents2005
03. 10. 2007
0 views

DemoStudents2005

interiorscapeplants2
07. 12. 2007
0 views

interiorscapeplants2

PRS328 Schechter
19. 06. 2007
0 views

PRS328 Schechter

ASEAN China
10. 10. 2007
0 views

ASEAN China

tpa 6040a4 overview
19. 06. 2007
0 views

tpa 6040a4 overview

2006 AHM Dissemination Update
17. 10. 2007
0 views

2006 AHM Dissemination Update

Bhat
21. 11. 2007
0 views

Bhat

Aho ealta2006
07. 09. 2007
0 views

Aho ealta2006

Fairness
14. 09. 2007
0 views

Fairness

Ch22
15. 11. 2007
0 views

Ch22

Ready Boost
19. 06. 2007
0 views

Ready Boost

05 asphalt institute
26. 02. 2008
0 views

05 asphalt institute

LightGina
20. 03. 2008
0 views

LightGina

Working Water Conaway
28. 12. 2007
0 views

Working Water Conaway

HERDING101Presentati on
19. 11. 2007
0 views

HERDING101Presentati on

currentshow
02. 11. 2007
0 views

currentshow

flowes class4
11. 12. 2007
0 views

flowes class4