Finite-element analysis on the parameters influencing the brittle crack arrest in steel plates

Abstract

With increasing strength and thickness of steel plates, the susceptibility to brittle fracture also grows, primarily due to the reduction in toughness of both the base metal and the weld zone. To maintain structural integrity and mitigate fracture risks in thick, high-strength steels—especially in applications such as ship hulls—advanced design strategies and materials with enhanced brittle crack arrestability have been introduced. The arrest performance is typically assessed by determining the brittle crack arrestability value (Kca) through large-scale experimental methods. However, due to the high cost, time, and equipment demands of such tests, alternative approaches using small-scale specimens and numerical simulations have been actively investigated to estimate Kca more efficiently. This study establishes an analytical model by conducting a parametric investigation of the key factors influencing Kca determination. The analysis incorporates yield stress variations influenced by temperature gradients, strain rates, and thermal effects, considering Young's modulus and strain rate dependency. Additionally, the study examines the influence of crack-growth increments and the impact energy effect on brittle crack initiation (K_IC). The reliability of the proposed model is validated by comparing its Kca predictions with experimental results obtained from the ESSO test.