Tensile tester and fracture toughness tester in one complete unit

L&W Tensile Tester with Fracture Toughness offers a simple and accurate way of measuring the fracture toughness, in accordance with the STFI method, as well as tensile stiffness, tensile strength, elongation, tensile energy absorption, breaking length, etc. in a single, easily programmable unit.

Measurement results with a minimum of effort

L&W Tensile Tester with Fracture Toughness is designed with special emphasis on ergonomics and high performance.
The notch for measuring the fracture toughness is made automatically by a built-in knife. A special holder is also provided to hold the test piece flat during the test.

Simple to preset

Interactive software makes L&W Tensile Tester with Fracture Toughness very easy to configure. The dialogue language can be selected by pressing a button, and up to 30 measurement programs can easily be preset and stored in the built-in memory.

Automatic starting of measurement

A further example of the many practical features of L&W Tensile Tester with Fracture Toughness is that the measurement sequence is started automatically as soon as the test piece is in place in the clamps. The clamps do not need to be replaced if test pieces of different widths are tested.

The wide measurement range of 7–1500 N (1.57–330 lbf) enables accurate measurements to be made on all grades of paper.

The clamping force is adjustable between 1000 and 6000 N (225–1350 lbf), and even extremely strong materials can therefore be reliably clamped for testing.

The measurement results are presented on the built-in and easy-to-read graphic display in the form of curves or numerical measured values. The built-in printer can also print out the results.

Measurement procedure

A test piece is loaded to fracture at a constant elongation rate. The instrument automatically records the tensile force as a function of the elongation. The computer uses the recorded data to calculate the tensile strength, tensile energy absorbtion and tensile stiffness.
Calculations based on the tensile testing data produce a JI curve as shown above. JI is a parameter that can be said to describe the stress condition at the tip of the crack.

A 50 mm test piece is clamped in the tester. The notch is cut automatically in the tester before the test piece is loaded to fracture. The fracture toughness JIC is defined as the JI value at the critical elongation νc of the test piece.

The instrument carries out all calculations necessary for obtaining the fracture toughness value.