Combined effects of in-plane and out-of-plane constraints on fracture behaviors in central-cracked stiffened plates: A model based on plastic zone size

Abstract

Fracture toughness and allowable loads are affected by in-plane and out-of-plane constraints, and the influences are studied in stiffened plates. Under small scale yielding condition, a new correction model of fracture toughness is developed by using the constraint parameter rp01/2 which is based on the size of crack tip plastic zone. Then the fracture behaviors are investigated under three kinds of situations: (i) Stress intensity factor (SIF) is focused on solely; (ii) SIF and in-plane constraint (i.e. T11) are considered; (iii) In the framework of correction model based on rp01/2, SIF and the combined effects of in-plane and out-of-plane constraints are taken into account. The results show that both in-plane and out-of-plane constraints have significant effects on fracture toughness, allowable loads and crack arrest effects, and their influences cannot be neglected in stiffened plates generally. The evaluations based on rp01/2 are more reasonable, because the proposed model considers in-plane and out-of-plane constraint effects comprehensively and the equation of fracture toughness is derived from the actual testing data.