ISO 3377-2_{Leather -- Physical and mechanical tests -- Determination of tear load -- Part 2: Double edge tear}

Test summary

ISO 3377-2:2016 specifies a method for determining the tear strength of leather using a double-edged tear. The method is sometimes described as the Baumann tear. It is applicable to all types of leather.

A rectangular test piece is prepared with a hole of a specified shape. It is placed over the upturned ends of a pair of holders, which are attached to the jaws of a tensile testing machine. The highest force exerted during the tearing of the test piece is recorded.

Test apparatus

A tensile tester capable of measuring displacement and applying a constant speed of grip separation. A suitable loadcell calibrated and fitted to the tensile tester.

Complimentary software for recording load and displacement and calculating results.

Test piece holders, as specified in the standard, with connections suitable for use with the tensile tester and loadcell.

Cutting equipment.

A thickness gauge.

Preparation

From the sample, cut the test pieces to the dimensions given in the standard. There should be a minimum of 3 pieces cut with the long axis parallel to the backbone. A further 3 pieces should be cut perpendicular to the backbone.

Measure the thickness of the test pieces in accordance with ISO 2589.

Test method

Adjust the apparatus so that the upturned ends of the test piece holders are lightly touching each other.
Slip the test piece over the upturned ends so that the ends protrude through the slot - make sure that the width of the upturned ends is parallel to the straight edges of the slot.
Press the test piece firmly onto the holders.

Start the test stand moving at a constant speed of grip separation (100 mm/min) until the test piece is torn apart.
Record the maximum force reached during testing.

Use the software to report the thickness of the leather (in millimetres) and the mean tear force (in newtons) indicating whether the test pieces are cut parallel or perpendicular to the backbone.