On stable crack growth

Deformation mechanism under essential work of fracture process in polycyclo-olefin materials

“…When a double edged notch specimen is loaded under uniaxial tension, the fracture is dissipated in two distinct zones such as fracture process zone (or essential zone) and plastic zone (or non-essential zone). The total work of fracture W f is expressed as the sum between the two parameters of the essential work W e and the nonessential work W p , as shown by Equation (1) [2][3][4][5][6]: (1) The first term is related to the instability of the crack tip and represents the energy required to fracture the polymer in its process zone which is surface-related whereas the second term is associated with the plastic work, which is proportional to the plastic zone volume, and represents the energy consumed by various deformation mechanisms in the surrounding outer plastic zone [7][8][9]. When the typical load-displacement curve of double-notched specimen shows a maximum point at which the ligament region is fully yielded and the yielding region is necked after maximum, then may be parti- (2): (2) where W y is the mechanical energy required for yielding of the ligament region and W nt is the energy required for necking and subsequent tearing.…”

“…The mechanical data in the vicinity of T g are very useful to optimize the molding conditions. The essential work of fracture (EWF) method developed by Broberg [2] has been conveniently used for the examination of fracture properties of ductile thin films. When a double edged notch specimen is loaded under uniaxial tension, the fracture is dissipated in two distinct zones such as fracture process zone (or essential zone) and plastic zone (or non-essential zone).…”

Impact fracture toughness evaluation by essential work of fracture method in high density polyethylene filled with zeolite

“…Recently, the EWF method that originally proposed by Broberg [12] has been progressively used to evaluate the fracture toughness of polymer matrix composites [13][14][15]. The total fracture work of a specimen having a sharp crack (W f ) is partitioned into EWF (W e ), i.e., the work required to create new surface in its process zone and the non-EWF or plastic work (Wp),i.e., associated with the work done by various deformation mechanisms in the plastic zone and volume-related.…”

Essential and Non-essential Work of Fracture of PI/SiO2 Hybrid Thin Films

“…Another method for characterization of the fracture behavior of ductile materials is called essential work of fracture (EWF), originally proposed by Broberg [9]. Compared with the J-integral method, the requirement of the specimen size for EWF method is plane-stress conditions, and the more attractive is that one only needs to know the ligament length of specimens rather than measure the crack extension as requirement of the J-integral method.…”