Strain gage measurement strain gage installation simutech. Vishay measurements group strain gage website strain gage installation manual me 302 lab schedule week dates lab topics assignment due dates 1 117 121 first week of semester no lab classes 2 124 128 overview, safety, uncertainty analysis statistical analysis 3 1 24 tensile testing data reduction overview homework 1a and 1b 4. The special alloys used in strain gauges exhibit a nearlinear ratio between their resistive and mechanical strains. For use with d6127, d6129, dbrw, ad6856, d6550 or d6745. The active gauge r 1 is remote from the instrumentation, and both it and its associated wiring are subject to resistance changes brought about by any variation in temperature. Associated with the strain gage is a measurement system. Comparing strain gage measurements to force calculations. Strain gage in this laboratory we design our first electronic device, an electronic weight scale.
This is a novel medical application that combines the strain gauge sensing technology, applied on a cantilever beam as an. Sensorcloud provides vis which allow your labview applications to communicate with sensorcloud. Strain gauges are available commercially with nominal resistance values from 30 to. In this laboratory, i successfully installed a cea240uz120 student strain gage onto a 6061 aluminum beam. Therefore, the strain has little effect on the second gauge, called the dummy gauge. Strain gages return varying voltages in response to stress or vibrations in materials.
Development and validation of experimental setup for flexural. The gauge is attached to the object by a suitable adhesive, such as cyanoacrylate. Me 302l cee 370l materials mechanics laboratory manual. I have to attach a strain gauge on a aluminum tube to measure 3d forces on it. In this part there will be a use of a strain gauge device which experiences a change of electric resistance when it is strained. Measurements i 12 bridge strain gauge labview tutorial duration. Use the arrangement that produces the maximum sensitivity. Connecting strain gages to a daq device national instruments. In order to compensate for such changes which the instrumentation would interpret as mechanical strain the gauge itself should be chosen, if possible, as one having temperature compensation for the material being tested. Figure 1 shows a strain gage with two electrical leads on the right side. Because the temperature changes are identical in the. The mechanical strain experienced by the test specimen, and thus also by the strain gauge, gives rise to resistive strain of the gauge element. Measurement of strain due to bending and axial loads.
Single opamp amplifier to adapt a quarter bridge strain gauge to the analog input of an arduino micro controller. I will use a wheatstone bridge for each strain gauge. This lab explores the concept of strain measurement using a strain gage. Lab 4 strain gage university of california, berkeley. They are designed to work for desktop applications and embedded devices lik the ni compactrio. Static strain measurement cantilever beam objectives.
The default is 120 gf is the gauge factor of the strain gauge v is poissons ratio. Building a low cost strain gage load cell amplifier the. In a halfbridge, boxes 1 and 2 are strain gages, and the others are resistors 5. I am using the strain gauge vi for labview, on the myrio. Strain measurement in a simply supported beam asee. Measure and record the resistance of each of the gages. This parameter is only required for certain bridge configurations. Reported in shows products that are verified to work for the solution described in this article. By using the ni elvis ii prototyping board and labview, students can automate a load reading from a strain gauge while learning how to build a simple. In fact you cannot use strain gage load cell without instrument amplification, since the sensitivity of the bridge is really low. The daqmx does have two vis for this, daqmx perform bridge offset nulling calibration. November 7, 2008 ryan carmichael swarthmore college.
Furthermore strain gages have a low resistance from 60 to 350 ohm depending on the models and feeding load cells with high excitation will heat strain gages up. A strain gauge also spelled strain gage is a device used to measure strain on an object. Begin to automate and customize your stain measurements using a builtin example that demonstrates the basics of continuously acquiring data from strain. This solution might also apply to other similar products or applications. Hello, i have a requirement to build a strain data acquisition systems using labview with all the signal conditioning facilities available with pxie4331. I will be amplifying the voltage across the resistor of the strain gauge, due to the readings being so small. Design, build and test a force sensor using strain gauges are provided, as well as development of the appropriate combination of strain gauges with other electrical components to obtain an electric voltage or current representing tensile, compressive or bending. Pdf strain gauge force transducer and virtual instrumentation.
Push on the beam so it deflects and make sure that the resistance changes. Students will take measurements from and calibrate a strain gage mounted on a cantilever beam and placed in a quarterbridge wheatstone configuration. Learn how to take strain gauge measurements with strain gauges using the builtin. Acquire data from strain gauges in labview nxg youtube. The bondable foil strain gauges manufactured by our micromeasurements are available with thousands of possible combinations of grid alloys, pattern designs, gauge lengths, backing materials, resistances, and optional features. All of our controllers are supported by unified pc based user and. The strain gauges used for measurement of deflection of a beam subjected to different point and uniformly distributed loading. This paper describes the implementation of labview, in an experiment in a. We will also use an instrumentation amplifier to gain up the signal. The key component is a strain gage, a resistor that changes its value in response to mechanical stress. Strain gage sensor system background reading please read the following material prior to this lab. Strain gauge load cells offer accuracies from within 0. Generalpurpose gauges are available in the following patterns. The change in resistance dr in a strain gauge of resistance r is very nearly proportional to the applied strain.
Dont use this circuit for instrumentation, there is no signal conditioning for the. In this lab, the active resistive transducers are the electrical resistance strain gages. Mcgraw hill college division 2 montero w et al, 2011, uncertainties associated with strain measuring systems using resistance strain gauges, j. In this case, it is possible to compare the strain measurements with calculated values. The inner working of a load cell differs based on the load cell that you choose. For a quarterbridge, box 1 is an active strain gage, and all other boxes are fixed resistance resistors.
This experiment is dedicated to study the main objective of resistance strain gages. They are highly accurate and reliable over a long period of time. Vsg is the voltage you read from the strain gauge bridge configuration indicates the type of bridge configuration in which the strain gauge is mounted. As an extra credit exercise, you will write a labview program to compute the power. Now i want some information about strain gauge calibrations.
Strain gauge scales use no springs and use a strain gauge transducer to measure the weight and display it digitally. This ratio is known as the gauge factor and is approximately equal to 20 for foil. Before performing this lab you must be familiar with. Click on windowsshow diagram to display your block diagram. Gauge behavior transverse sensitivity use of the fe model. So the main attractive feature for the customer is the offset nulling and shunt calibration. With labview, these equations are included in the convert strain. You will need to run the program to auto tune the bridge once again. Sketch in your lab notebook a bridge circuit in which the two gages can be used to measure the strain in the beam when it is loaded as a cantilever beam. Labview for everyone graphical programming made easy and fun, third edition. Connect the bendix connector attached to the wire junction to the rear of the 2311. Connect the data cable between the strain gauge amplifier and the port on the back of the cantilever beam. They make it simple to authorize devices, register sensors, and send data from within your labview code.
For th is lab, materials will assu med to fall in to the linear elastic region, using youngs modulus to relate stress and strain 1. When using a strain gage, you bond the strain gage to the device under test, apply force, and measure the strain by detecting changes in resistance. A rugged abs ip50 enclosure makes this usb load cell converter suitable for all environments. Plug the power cord from the bottom rear of the 2311 into the bench power strip. How to programmatically create a strain gage calibration. Force measurment system based on strain gauges engineering. Smyser is an assistant academic specialist and the lab director of the. With a resistance type strain gage, strain is measured by detecting the change of resistance in. Recent strain gage measurement applications by simutech include automotive radiators, a helicopter airframe, a forging press, a.
Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. However, any changes in temperature will affect both gauges in the same way. R, and a second gauge is placed transverse to the applied strain. Strain measurements are applicable to a wide variety of structures including industrial equipment, turbomachinery, aircraft, piping, automotive components and electronics. Measurements i 14 bridge strain guage labview tutorial. Then they will measure the natural frequency of the beam assembly by applying a fast fourier transform to the response of the beam due to an impulse. The focus of this thesis is the design of a vi that will collect and plot force and moment data from a six component strain gauge balance and yield real time, nondimensional, force and oment coefficients in six degrees of freedom. Digitize any combination of channels at 166,000 samples per second aggregate. E 1 this lab uses pairs of strain gages, applied perpendicular to each other. The metallic strain gauge consists of a very fine wire or, more commonly, metallic foil. The dscusb strain gauge to usb converter is a compact, high performance strain gauge digital signal conditioner with usb connectivity aimed at applications which require highaccuracy measurement repeatability. Labview sdk lordmicrostrainsensorcloud wiki github. A load cell works by converting mechanical force into digital values that the user can read and record.
Compatible with labview, dasylab, matlab, origin, c and visual basic software. It can be used to calculate forces, pressures, displacements, and a whole variety of other mechanical material properties. This laboratory experiment is intended for students to. Applying strain gauges properly to get good data is. Labview, a user interface program, is used to translate changes in wire resistance on the strain gage into a numerical value, in microstrains. K is a constant known as the gauge factor and is the relative strain. Laboratory 3 strain gage sensors national instruments. As an extra credit exercise, you will write a labview program to compute the power spectrum of the output from your strain gage circuit before and after the lowpass filter. Building an analog circuit to obtain deflection measurements using a strain gage in this experiment, you will build an analog circuit for using a 120. The fx1901 is an inexpensive 1% strain gauge that can be used for a variety of applications.
Labview strain gage sensor integration this manual. Labview graphical programming4th edgary and richard feb. Labview lab oratory v irtual i nstrumentation e ngineering. It is designed to measure, condition rectify and filter, and display the feedback signal derived from ac bridge strain gauge systems. In this paper, experimental setup for stress measurement using ni labview has been presented. Rg is the strain gauge nominal resistance value in ohms. Technological science 1 strain gauge laboratory report by akash sherchan student i. Strain is the 2 nd most common physical sensor measurement in the world behind temperature. Begin to automate and customize your stain measurements using a builtin example that demonstrates the basics of continuously acquiring data from strain gages. Pdf implementation of a labviewbased automated wind. Check that the power to the 2311 signal conditioner is shut off.
522 1189 891 402 835 814 944 1516 636 1318 1497 892 670 667 645 1153 174 573 1245 917 645 475 1434 761 1527 367 808 325 1294 473 1391 835 871 522 1522 315 696 1313 267 631 1318 1053 555 1312 928 381 757 322 1425 224