Scott bond internal strength of paper or board

This test measures the energy required to rapidly delaminate a sheet-type specimen. A z-directional rupture is initiated by the impact of a pendulum having both a controlled mass and a controlled velocity. The geometry of the apparatus causes the tensile stress to be rotational with negligible shear stress on the specimen. The energy is absorbed during the elongation and stretching of the sample's fiber network before rupture. The test is a measurement of strain energy per unit sample area, which is proportional to the area under the stress-strain curve.