How does video extensometer work?
How does video extensometer work?
Video extensometry incorporates a high-resolution digital camera with advanced real-time image processing to make highly precise strain measurements of a variety of specimen types. The video camera captures the image, which is transferred via an IEEE 1394 (Firewire) interface to a PC or laptop computer.
Why is extensometer more accurate?
Contact-type Measurement Extensometers The mechanical parts that transfer extension, via knife edges, from the specimen to the internal transducer are short and stiff. There is practically no relative movement between the specimen and the extensometer, resulting in a high level of measurement accuracy.
What is an extensometer and how does it work?
An extensometer is an instrument that measures the elongation of a material under stress. The elongation of the material is a physical deformation of the sample and is a type of strain associated with tensile measurements. There are two classes of extensometers, which vary in the method the measurement is performed.
Is an extensometer a strain gauge?
An Extensometer is a type of strain gauge that is used in conjunction with a Universal Testing Machine in order to measure elongation at high accuracies. Extensometers come in different shapes and sizes depending on the type of sample being measured.
Why is an extensometer needed?
Extensometers are generally used in industries where manufacturers need to test tensile strength of the materials they use, to determine if they can withstand the amount of strain typically put on them. Extensometers are also used in field settings, such as mines.
What is borehole extensometer?
An extensometer is a measuring device designed to measure changes in the length of a specific object. Borehole extensometers (e.g. SMART MPBX) are specifically designed to fit easily in a standard size borehole; for example, the type drilled out in order to install stabilizing cable bolts.
Why extensometer is removed?
Extensometer has to be removed before sample fails to prevent damage to the device.
Are extensometers reusable?
Extensometers measure strain (or displacement) directly on the test specimen. Extensometers are reusable and last for years, and they are very cost-effective compared to adhesively bonded strain gages or digital imaging measurements.
What are the types of extensometer?
There are two main types of extensometers: contact and non-contact.
Why is extensometer more accurate than crosshead?
Crosshead movement is measured using a high-resolution encoder. When you move the crosshead with no specimen installed, the reported measurement of that movement is often more accurate than for many extensometers.
Who invented extensometer?
An extensometer is a device that is used to measure changes in the length of an object. It is useful for stress-strain measurements and tensile tests. Its name comes from “extension-meter”. It was invented by Charles Huston who described it in an article in the Journal of the Franklin Institute in 1879.
What is settlement extensometer?
Extensometers are used to measure movements of soil and rock along a single axis. Applications for extensometers include: Monitoring settlement in excavations, foundations, and embankments. Monitoring compression of piles and soil under piles. Monitoring spread in embankments.
