Validation of Cyclic Void Growth Model for Fracture Initiation in Blunt Notch and Dogbone Steel Specimens

Abstract

Tests and finite-element analyses of blunt notch and dogbone specimens are presented to demonstrate the application and validation of the cyclic void growth model (CVGM) to evaluate the initiation of ductile fracture under cyclic loading in steel structures. Modeling concepts and procedures for characterizing the CVGM material parameters using notched bar tests are described. Accuracy of the model is validated through a series of cyclic tests of 14 blunt notch compact fracture specimens and four dogbone specimens. Four types of moderate to high strength structural steels are investigated (two types of A572-Grade 50, A514-Grade 110, HPS70W). The test specimens reflect stress and strain conditions encountered in structural steel components and provide sufficiently strong stress and strain gradients to validate the characteristic length assumptions in the model. Detailed finite-element analyses that employ the CVGM criterion are shown to predict fracture with good accuracy across the specimen geometries, steel types, and loading histories.