What is Strain gauge: Definition and 47 Discussions

A strain gauge (also spelled strain gage) is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable adhesive, such as cyanoacrylate. As the object is deformed, the foil is deformed, causing its electrical resistance to change. This resistance change, usually measured using a Wheatstone bridge, is related to the strain by the quantity known as the gauge factor.

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  1. M

    B My strain gauge on a cantiliver beam is reading 0.040V before force is applied...

    i connect strain gauge on cantiliver beam and getting reading 0.040v before force applied , the theory said that bridhe should be balance mean=0 1) does 0.040 acceptable to carry on work or 2) how can i make it to 0so that it balanced
  2. M

    How to connect this strain gauge?

    recently i bought this strain guage where vender said it is 4bridge, i am not sure how to connect this in wheatstone bridge , i have 120 ohms resistors, and 120ohm strain gauge. please need guide thank you.
  3. M

    I The multimeter is not displaying mv of strain gauge in circuit

    i have made the wheatstone bridge( 3 resistors and 1 strain gauge) circuit but multimiter is not displaying anything , please need guide
  4. D

    I think I found a strain gauge

    I disassembled an electronic scale. I removed a piece from the corner. I think it is an strain gauge. When I Press on it a reading appears on The liquid crystal display. It might Say 9.6 or 10.8 or 11.5. I used a multimeter to measure it resistance. It 992 ohms. Unless I press on it. Then its...
  5. J

    Is strain uniform in a material?

    Hello, I am working on a project for an EE class and am brushing back up on the basics of strain and stress. My question was to do with how strain works in a material and if it is constant throughout. Say for example you had a setup like this The change in resistance the strain gauge...
  6. A

    How do I use full-bridge strain gauge circuit to measure F?

    Hey all, I am using a Wheatstone bridge with 4 strain gauges as resistors. I have a formula for the output voltage (Vout). My questions is how do I make it so instead of voltage I measure force? Do I simply apply a set max. force (let's say 140N), see what voltage I get (Vout,max) and then use...
  7. adamaero

    Simple strain gauge in rectifier, last part of the problem

    Homework Statement Homework Equations The Attempt at a Solution I do not understand this last part: Is this needed? The divide by two is the voltage divider, correct?
  8. E

    Pipeline bend calculation from strain gauge data

    Hi all, I'm doing a stress analysis and I’m considering 3 buried pipelines carrying oil. Vibrating wire strain gauges have been installed in different sections for a total of 468 strain gauges. These have been arranged on the surface of the pipelines 120°apart: This pipelines have...
  9. T

    B What is a good physical reference for microstrain?

    I can say that the distance between my knuckle and my finger joint is 1~ inch, that a baseball weighs ~1 lb, and ~60 joules is the feeling of dropping a bowling ball on your foot. I'd like to understand strain in this way, can anyone offer a common place reference? Also, I know strain is...
  10. D

    How to Waterproof a Strain Gage?

    Hello all, Our project needs to implement a force (strain) gage underwater for one of our tests. Our budget is pretty tight and we can't afford a wash-down strain gage that can support the forces that we will be operating at (~500 lbs). Does anybody know a way to hermetically seal a strain...
  11. M

    Troubleshooting a 350 Ohm Strain Gauge Installation

    Hello, I was wondering if anyone can help me out with this one. I am installing a 350 ohm strain gauge as shown in attached figure. I am expecting to see 350ohm value between terminal 1 and 2. I have checked the values for the following terminals. 1) 5 & 6 = 350ohm (PASS) 2) 3 & 4= 350ohm...
  12. Y

    Strain Gauge Formula Derivation

    Using R = ρL/A, I am trying to get this formula, which is the change in resistance due to change in length, area, and resistivity. ΔR = (∂R/∂L)ΔL + (∂R/∂A)ΔA + (∂R/∂ρ)Δρ I understand the above conceptually, but I am confused about why we are multiplying by terms ΔL, ΔA, and Δρ. Intuitively, I...
  13. A

    Engineering Help with Wheatstone Bridge Strain Gauge Circuit

    Homework Statement Given your average Wheatstone Bridge with R1 R2 and R3 unknown resistor values and R4=RG= strain gauge, how to solve for the resistor values given only input voltage and the value of the resistances between the resistors?[/B]Homework Equations Not Sure[/B]The Attempt at a...
  14. S

    Designing a Strain Gauge Load Cell: Q&A on Force Measurement

    Hello, I'm trying to design a strain gauge load cell for force measurments. I have few questions regarding that. Q1: how to calculate the minimum froce that my load cell can detect? Q2: how to calculate the FSO(full scale output) of my load cell? Q3: Is there any way to measure the...
  15. S

    Calculating Strain Gauge Grid Line Output: A Step-by-Step Guide

    Hello, I would like to know, how to calculate the number of grid lines( or loops) in a strain gauge. I'm trying to calculate the output form the each grid lines. Thanks in advance
  16. F

    Strain Gauge Load Cell Questions

    I am not a (real) engineer, but have undertaken an ambitious project which contains some technical intricacies I have to learn on the fly. My first question (of many to come no doubt) is about strain gauge load cell technology - specifically powering the device. My project requires a battery...
  17. C

    Strain gauge force sensitivity

    Hello, I'm new here and that's because I've run into a problem I can't reliable find anywhere else. I guess I need some personal experience or input from someone. I'm designing a force sensor for a project of mine, it will be measuring force in three orthogonal directions. Now, I'm confident...
  18. S

    How to connect strain gauge in the form of wheatstone bridge

    HAI I am SYED , i am doing my project using strain gauges. Problem description: I have 4 strain gauges bonded to an octagonal ring. The strain gauge i am using is METAL FOIL TYPE , GF(gauge factor) -2 and 320ohm resistance. The strain gauge has two terminals ,my question is (1) Can anyone...
  19. S

    Strain Gauge Bonding: Permanent & Chemical Options

    I have a few strain gauges that are going onto the suspension of a race bike. I've never installed these things before. While I have found a lot of information on installing them, I am having a hard time finding many adhesive and chemical options. It seems a lot of them are non-permanent, or...
  20. X

    Strain Gauge Angle Homework question.

    [a]1. Homework Statement [/b] I thought it would be easier to post a picture since this way the drawing can be seen. I'm having a hard time deciding what angles to use with the relevant equations, see below. Homework Equations I know that: Ex' =...
  21. L

    Engineering Reducing noise in strain gauge using an RC circuit

    Vibrations of a motor (40Hz) cause noise on the signal of a strain gauge that monitors load on a cantilever that measures periodic load changes at the rate of 1/minute. Design a filter that reduces the signal caused by the vibrations by 90%. I thought about a low pass filter that has a cut...
  22. D

    Thevenin equivalent for strain gauge bridge

    A strain-gauge bridge is made up of four resistive elements, each element having an unstrained resistance equal to R, as shown in the diagram below. When a strain is applied to the bridge elements R2 and R4 increase in resistance by an amount ΔR, whereas R1 and R3 decrease by ΔR, where...
  23. D

    Strain Gauge recommendation

    Hi can someone please recommend a strain gauge to measure mass flow rate of a pneumatic conveying system. The full bridge circuit strain gauges are to be placed on a cylindrical cantilever beam with a length of roughly 160-170mm and a diameter of 36mm and made of iron. From what I have read...
  24. K

    Engineering Strain Gauge Project Circuit Question

    Design a circuit that uses a stain gauge to create a voltage related to the strain experienced by the gauge. The strain gauge should remain electrically isolated from the ground. The DC common mode voltage should be minimized. Only stain-related signal to be measured does not have any...
  25. R

    Understanding Strain Gauges: Measuring Mechanical Strains in Structures

    I am studying strain gauges at uni and was wondering if you could clarify for me how they may be used to measure mechanical strains in structures like towers, houses etc.. I know that it is possible to use a mechnical gauge that measures the development of a crack (see wiki)but I can't work...
  26. E

    Shunt Calibration of a Strain Gauge

    I've recently been researching how to measure strain using strain gauges. I came upon the subject of shunt calibration and hit a mental roadblock. From what I understand, shunt calibration simulates a strain across a strain gauge using a comparatively large resistor placed in parallel with...
  27. Saladsamurai

    Wheatstone Bridge Strain Gauge Question

    Homework Statement I recently did a bending lab with a WB Strain Gauge in a bunch of different configurations. One measurement in particular is bothering me. Referring to the figure below, there are four strain gauges, Yellow, Orange, Black and Red mounted to a cantilevered beam with an...
  28. H

    Convert Strain gauge readings to stress

    Hello i am trying to convert the strain gauge readings i took in a lab from an I beam that was subjected to torsion. I am trying to convert the microstrain readings to stress and shear stress. I have the following information the Yield strength of the I beam and the youngs modulus but not the...
  29. B

    Strain gauge data acquisition board?

    Ok, so what I am looking for, as the title suggests, is a strain gauge data acquisition board. Currently, we have been using all sorts of National Instruments stuff to obtain our goals. To this point they have worked fine, but now we need to seriously downsize for a new lab device we are...
  30. T

    Strain Gauge Placement on Cylinder

    1. Problem Statement: I am trying to measure the radial (#s 3-6) and hoop (#s 1, 2, 7, 8) strain (and from that, stress) present in an aluminum cylinder. I am trying to use a standard full wheatstone bridge setup, but am having trouble settling on a setup that would give me an accurate...
  31. J

    T-delta rosette strain gauge

    Homework Statement For experimental validation of a design based on FEA, a prototype was tested using strain gauge rosettes at critical locations in a typical t-delta configurations, consisting of 3 gauges: A, B, C and fourth (extra) gauge D. D normally serves as a check on the strains recorded...
  32. A

    Strain gauge - determination of x and y strains

    Homework Statement Determine x and y strains in order to construct a Mohr's circle of strain. A 2-gauge Wheatstone (the third/middle gauge was not working), with gauges 90-degrees apart, was attached to a specimen steel plate 15-degrees offset from the x and y axes. An axial load was applied...
  33. O

    Calculate Tensile Stress with Strain Gauge

    A strain gauge has a unstrained resistance of 120 ohms, gauge factor of 2.0 is connected to steel girder so it experieces tensile stress. If strained resistance of gauge is 120.13 ohm. How do i calculate the tensile stress value? I have looked all over the internet for equations relating but...
  34. O

    Calculating Tensile Stress Using a Strain Gauge

    A strain gauge has a unstrained resistance of 120 ohms, gauge factor of 2.0 is connected to steel girder so it experieces tensile stress. If strained resistance of gauge is 120.13 ohm. How do i calculate the tensile stress value?
  35. C

    Will our strain gauge accurately measure small forces on a baseball?

    Hi, my group and I are doing an experiment on forces experienced on a baseball. Our setup involves the baseball attached to a motor, which is coupled to a cantilever beam (1/2 inch thick, 7 inch long aluminum rod). The beam has a strain gauge attached to it and we are recording data with...
  36. Cyrus

    Strain Gauge Tutorial: Selection & Tradeoffs

    This is a very good little tutorial on how to use strain gauges and the tradeoffs found by using different sizes. http://www.abacus.co.uk/jkcm/cache/fl0008816.jpg http://signalprocessing.prosig.com/FatigueTesting/strain-gauge-close.jpg[/URL]...
  37. B

    Troubleshooting Mass Measurement Experiment w/ Strain Gauge Sensor

    imdoin an experiment with a strain gauge sensor to measure mass. the 2 strain gauges are in a wheatstone bridge and the wheatstone bridge is connected to 3 741 op amps to amplify the signal. i need an output of cetain voltages for certain masses input. My circuit is giving an output to high...
  38. F

    OCR Physics AS Level - Strain gauge, temperature, resistance

    I have an assignment in which I have to design a laboratory experiment (not real, only in theory i.e. planning) to investigate how the resistance of a strain gauge attached to a piece of wood varies with the temperature of the wood. *IMPORTANT* My teacher said keep it simple, do not over...
  39. J

    Quarter- bridge strain gauge circuit

    Could anybody help me please? :cry If I have quarter- bridge strain gauge circuit, where strain gauge will have its initial resistance and i will add another 3 resistors, 1 on the same side like strain gauge, and another 2 on the opposite side, so I will balance circuit and my voltmeter...
  40. B

    Strain gauge to measure wood expanasivity.

    Hi! Im measuring how much wood expands in different temperatures using a strain gauge. do i need to use a wheatstone bridge circuit schematic? or else how do i heat up the wood without spoiling the strain gauge. Actually how will i heat up the wood anyway? Also how would i draw a diagram to...
  41. F

    Does the resistance of strain gauge increase when temperature increases?

    Hello, could someone help on this question?? ok, I'm trying to find out how much a piece of wood expands and contracts with changes in humidity and temperature, I'm sticking a strain gauge on the wood to detect the expansion and contraction of it. my question is if the temperature increase...
  42. B

    Solving Strain Gauge Problem: Young's Modulus Calculation

    Homework Statement In a bridge circuit R1 is bonded to a cylindrical specimen of diameter 25.08mm. R4 is 160.1ohm, R3 is 2502.7ohm and R2 at balance is 2505.8ohm when the specimen is unloaded and 2511.7ohm when it is loaded with 50kN. the gauge factor of the strain gauges was 2.10. determine...
  43. I

    Wheatstone bridge/ strain gauge question

    Need to do an experiment where I masure the strain of wood due to changes in temperature. I believe I need to use 2 strain gauges, one to measure the strain and the other to act as a dummy to cancel out any affects that heating will have on the strain gauge. I also know that a wheatstone bridge...
  44. H

    Investigating Wood Expansion & Contraction w/ Strain Gauge

    Hi i have just been given my physics coursework and wondered if anyone had any pointers or tips on how to answer? The question is on the expansion and contraction of wood with changes in temperature and humidity using a strain gauge. We have to explain how we would use lab equipment to...
  45. X

    Some Strain Gauge Theory Help

    First, I am not the greatest at LaTex so if I screw this post up I will go back and try to clarify. I will skip some steps, but get the general gist of everything. Ok, I am following the derivation of the resistive strain gauge equations starting from the basic form of resistance of a wire...
  46. E

    What Factors Influence the Design of a Strain Gauge?

    Hello. I am currently working on a project which requires me to deisgn a strain gauge. However, even though I have done quite a lot of research, I am still unable to find the answers to the questions that I have. They are: 1) How to decide the resistance (decided by the grid length as...
  47. J

    (-Planning Exercise - Strain gauge Coursework Help -)

    (--Planning Exercise - Strain gauge Coursework Help!--) Hi I've been stuck for several days in the early stages of my coursework i would have asked my tutor but I have been forced to stay home due to a very bad chest infection :frown: I will first provide a full transcript of the question...
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