Fracture mechanics analysis of generalized compact tension specimen geometry using the mechanics of net-section

• Published in: Engineering fracture mechanics Vol. 222; p. 106703
• Main Author: Ravi Chandran, K.S.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.12.2019; Elsevier BV
• Subjects: Compact tension; Deformation; Equivalence; Fracture mechanics; Geometric correction factor; Mathematical analysis; Modulus of elasticity; Net-section; Specimen geometry; Splitting; Strain; Strain energy; Stress intensity factor; Stress intensity factors; Wedges; Geometric correction factor; Fracture mechanics; Stress intensity factor; Net-section; Strain energy
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2019.106703

[Display omitted] •A new approach based on net-section fracture mechanics provides a broadly useful expression for stress intensity factor.•A single expression is found to be sufficient for compact tension, extended compact tension and wedge splitting test specimens.•The approach is based on the change in net-section strain energy, which is equivalent the Griffith’s fracture theory.•The expression describes the cack behavior of C(T), EC(T) and WST specimens in an excellent manner. Fracture mechanics analysis of a generalized compact tension specimen, on the basis of the mechanics of deformation of the net-section, is shown to provide a simple and a broadly useful expression for stress intensity factor calculations. A single analytical expression is found to be sufficient for the characterization of crack behavior in compact tension, extended compact tension and wedge splitting test specimens without any restriction on the specimen length (or height) and width. The analysis is enabled by the concept of the change in net-section energy, which is determined by summing the changes in strain energies of the net-section of the generalized specimen for tension and bending deformation modes, which result from the introduction of the crack. This is equivalent in concept to the increase in strain energy upon the introduction of the crack, as in the Griffith’s fracture theory. The square-root of the change in net-section strain energy parameter multiplied by the elastic modulus provides an expression that is equivalent to the conventional stress intensity factor expression. The application of the net-section based expression to the standard compact tension, the extended compact tension and the wedge-splitting test specimens shows very good agreements with the crack behaviors as expressed by the stress intensity factor expressions for the respective geometries. The proposed method enables easy analytical determination of stress intensity factors for any asymmetrically-loaded mode-I crack problem.