Carbon fiber tensile strength testing – Dia-Stron Ltd., UK

The tensile strength of carbon fibers is an area of study gaining traction. This is because of carbon fiber’s reputation as a new-age material that can replace traditional materials such as wood, metal, and glass fiber. The numerous advantages it offers gives carbon fiber the potential for widespread adoption in key industries such as aerospace, wind turbines, and automotive. This has led to a lot of interest in analysing different physical properties of carbon fibers, amongst which tensile strength is the one most analysed about.


Instruments for testing carbon fiber tensile strength

Dia-Stron is a world-renowned manufacturer of instruments for analysing different properties of single fibers. Their first instrument was designed for testing the tensile strength of single hair fibers. But soon after, they realized the potential for customizing their instrument to measure the tensile strength of other materials such as carbon fibers.

A real challenge in testing carbon fibers is in handling, manipulating, and mounting them onto the instrument. The brittle nature of these fibers poses a problem since more of them will be broken by the time they are loaded for measurement. The card frame method has proved to be cumbersome, time consuming, and error prone.

Dia-Stron offers a solution in the form of their patented plastic tabs with alignment features. Each filament will have to be glued onto the plastic tabs with a special UV-curing adhesive before being loaded onto the instrument or the automation platform. These plastic tabs keep all the fibers at a consistent gauge length, aligned, and square. These tabs are compatible with all Dia-Stron instruments.

The Dia-Stron instrument which is widely used for accurately evaluating the tensile strength of carbon fibers is the LEX820.

LEX820 specifications

Force range

0 to 2.5 N (or)

0 to 20 N

Force resolution

0.05mN (2.5 N)

0.5 mN (20 N)

Speed range

0.01  to 2.6 mm/sec

Extension range

3 – 53 mm

Displacement resolution


Displacement accuracy

50 mm

Load cell linearity

±0.1% full scale

LEX820 – High resolution extensometer

The LEX820 is a specially designed tensile testing instrument for brittle filaments such as the carbon fiber. The whole setup consists of the LEX820 module, the UV1000 control unit, and the UvWin software. Movement is driven by a DC micrometer which offers exceptionally smooth travel with high positional repeatability. This aids in accurate measurement of strain data.

Based on your requirement, you have the option of choosing between a 2.5N and 20N load cell. To increase throughput, you can integrate the instrument with the ALS1500. This will automate the system to measure the tensile strength of one carbon fiber after the other without the need for any human intervention.

Ultimate tensile strength of carbon fiber

Generally, tests conducted all over the world have provided the result that the average ultimate tensile strength of a single filament of carbon fiber is 4137 MPa. The T1100G from Toray is believed to be the strongest human-made fiber and is used in primary aircraft structures, rocket parts, and sports equipment. A single filament of Toray T1100G has been found to have an ultimate tensile strength of 7000 MPa.

Dia-Stron LEX820 price

Agaram Industries is the exclusive distributor of Dia-Stron in India. To get a quotation with the LEX820 price, you can fill up this form or directly send an email to

Contract testing for tensile strength of carbon fiber

Dia-Stron also offers contract testing services for the tensile strength of carbon fibers. It has a dedicated laboratory in UK with laboratory staff equipped to perform a wide range of tests. This is an efficient, cost-effective way to ensure you get valid and repeatable results. If you would like to get your carbon fibers contract tested with Dia-Stron, just send an email to and we’ll get back to you with all the details.

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