TSO – TENSILE STIFFNESS
Purpose of the test
This test is performed to determine the Tensile Strength Stiffnes in MD and CD and the orientation angle in CD of paper.
Procedure
Operate the instrument in accordance with the manufacturer’s instructions.
Leave the samples exposed for 24 h to 23°C and 50% R.H., according to ISO 187.
The principle of the method is that the velocity of ultrasonic pulses in the material depends on the material’s elastic properties.
The Tensile Stiffness Index (TSI) of a material is proportional to the square of the velocity of an ultrasonic pulse in the material. The TSO Tester measures the velocity of ultrasonic pulses in several directions in the plane of the sheet and calculates and reports the TSI and its orientation. Since there is no standardised method for checking and calibrating the instrument, choose the contact pressure and perform the tests according to the instructions given by the instrument manufacturer.
Longer side is parallel to the machine direction (MD).
Make the test in MD with the marked side upwards.
Report 10 measures of TSI in MD and CD and of orientation angle in MD, their mean and standard deviation calculated to 3 significant figures.
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Nr. of samples
12 test pieces per level.
Sample size A4
Levels
TSO index MD:
Level 1: 8.0÷12.0 kNm/g
Level 2: 9.0÷13.0 kNm/g
Level 3: 9.0÷13.0 kNm/g
Level 4: 8.0÷11.0 kNm/g
TSO index CD:
Level 1: 2.0÷4.0 kNm/g
Level 2: 4.0÷6.0 kNm/g
Level 3: 4.0÷6.0 kNm/g
Level 4: 3.8÷5.4 kNm/g
TSO orientation angle:
Level 1: -2.0÷2.0 °
Level 2: -5.0÷0.0 °
Level 3: -4.0÷-0.0 °
Level 4: 0.0÷4.0 °
Reporting
Report 10 measures of TSI in MD and CD and of orientation angle in MD, their mean and their standard deviation. All to three significant digits.