Engineering estimation method of unified constraint parameters for semi-elliptical surface cracks in plates. (15th April 2020)

• Record Type: Journal Article
• Authors: Xiao, J.Y.; Wang, G.Z.; Tu, S.T.; Xuan, F.Z.
• Is Part Of: Engineering fracture mechanics. Volume 229(2020)
• Publication Date: 2020-04-15
• Subjects: Unified constraint parameter -- Crack -- CTOD -- Solution -- Plate; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2020.106935
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: Engineering estimation methods and solutions of unified constraint parameters are investigated. Solution of constraint factor m relating CTOD to J -integral for cracks in plates are obtained. Solutions of unified constraint parameters Ad and Ad * can be estimated based on the m solution. Overall constraint characterized by unified constraint parameters for cracks in plates is analyzed. Abstract: To develop fracture assessment methodology based on in-plane and out-of-plane unified constraint parameters for various cracked components, the engineering estimation methods and solutions of unified constraint parameters should be investigated and developed. In this work, the relationship between J -integral and crack tip opening displacement (CTOD) for semi-elliptical surface cracks with a wide range of sizes in plates under bending and tension loads have been calculated by extensive three-dimensional finite element analyses. The results show that the relationship between J -integral and CTOD along the crack fronts is approximately linear. The plastic constraint factor m relating CTOD to J -integral can be determined from the J -CTOD relation lines. The factor m solutions for the cracks in plates are obtained. Based on the m solutions, the solutions of two new unified constraint parameters Ad and Ad * can be estimated and obtained. The estimation methods of the unified constraint parameter solutions in this work may be used for other cracked components. The overall constraint levels characterized by the unified constraint parameters for the cracks in plates also are analyzed. The results show that lower constraint occurs at free surface part of a crack, and higher constraint appears at deeper part. The constraint levels increase with increasing crack depth and length. The constraint of a crack under bending load is higher than that under tension load.