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The Usefulness Of A Strain Gauge

June 7, 2011 | Author: | Posted in Education

The action of external forces on an object that is not moving causes strain and stress on the object. Strain is defined as the deformation and displacement that the object experiences whereas stress is defined as the resisting forces that take place in the object. The deformation that happens on an object is measured through a device known as a strain gauge. In order to know the amount of deformation that has taken place, you should divide the deformation of the initial length of the object by the initial length of the object.

The instrument changes the mechanical motion experienced in the object into a signal that is electric. Changes in resistance, capacitance or inductance are usually proportionate to the stress experienced by the sensor in the instrument. As an example, the length of a wire that has undergone tension increases slightly and the cross-sectional area of the wire reduces. After this occurrence, there is a change in the resistance of the wire, which happens proportionately to the strain sensitivity.

Often, these devices feature a backing that is flexible and insulating, which supports the metal foil pattern. When the measurements to be performed are temporary, one can use cynoacrylate to attach the device to the object. On the other hand, if the measurements are lengthy, the best adhesive to use would be epoxy glue. Preparing the area where the gauge will be placed is essential and a good way to accomplish it is through the use of a smoother such as sandpaper and to remove any oil on it.

The strained object is often deformed and this causes the foil to deform also and the result is that its electrical resistance is changed. This transformed resistance is measured by using a Wheatstone bridge. A quantity identified as the gauge factor is used to relate the resistance to the deformation. The object undergoes a small change in length and due to this; the change unit used is given in terms of 10 raised to the power of 6 in order for the readings to be meaningful.

The strain gauge usually only measures the local deformations that happen on objects and it is possible to design them in small sizes so that they can be able to perform a finite-like analysis on the object. The sensor is what makes them useful in studying the fatigue that materials experience. It is also possible to design their configurations in a manner that makes it possible for the instruments to measure various deformations and displacements that are applicable to differently sized objects and components.

For instance, a configuration that is bi-axial can be utilized in measuring along different planes of objects like those of cutting instruments of objects that have holes. Measuring deformation in this way involves placing two different appliances in a right angle so that they can create a common point. This allows someone to measure deformation along different axes. In addition to this, the devices can come in designs that allow them to make thermal measurements.

This is particularly applicable when it comes to measuring the deformation and displacement that occurs on railway lines. The forces that are applied to railway lines that are continually welded occur laterally, longitudinally and vertically. When the devices are able to measure these forces, they can provide data that is very important for maintenance crews because they will help them ensure the safety of high speed and long distance trains.

The importance of the strain gauge cannot be understated since it plays a significant role in many industries. It is useful in mining, architecture, construction and building roads. The device also has a great role to play in the media, medicine and legal services. It is important to ensure that you buy this gauge from manufacturers who are reputed to make high quality measuring devices.

Choose from an expansive selection of state-of-the-art scientific technologies including the linear position sensor, calibration systems, load cells, mass flow sensor, and load cell. These specialized tools are very popular among the research and development industries.

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