Scaling laws for elastoplastic fracture

Scale or size effects in fracture result from the interaction of some energ ies dependent upon volume and other energies dependent on area (cube-square scaling). The known scaling laws within the lefm and nlefm ranges and with in the rigid-plastic range are highlighted along with applications. This pa per derives for the first time the scaling laws for elastoplastic fracture based on linear power-law behaviour which span the different regimes from l efm at one end of the spectrum to extensive ductile fracture at the other. The existence of a master-curve of normalised load (X) over bar vs normalis ed displacement (u) over bar is demonstrated on which fall all results from different size geometrically-similar testpieces up to first cracking. Crac k propagation in larger bodies begins at smaller normalised loads and displ acements than geometrically-similar small bodies. Large bodies behave as if their fracture toughness were given by (R/lambda), where lambda(> 1) is th e scaling factor, rather than by the material value R. Propagation behaviou r is path-dependent and each size cracked body has its own (X) over bar-(u) over bar propagation plot. This explains departures from 'geometric' (lamb da 3) scaling well-known in the literature. Comparison is made with old and recent experimental results.