Review and comparison of methods to measure paper fracture energy

Fracture energy and its relationship to paper runnability remains a topic of on-going interest. A number of measurement techniques have been developed to measure the fracture energy of paper. These include single specimen, multiple specimen and Liebowitz non-linear forms of the J-integral technique [1], the Essential Work of Fracture (EWF) method [2] and a variant simplified form using cyclic loading [3], and the measurement of the energy consumed in cohesive crack opening [4]. A modified form of the Liebowitz non-linear fracture energy has been developed as a commercial instrument by STFI [5, 6].