Open Access

ABSTRACT

Three-Dimensional Fracture Mechanics: Bridge the Gap from Laboratory to Engineering Structures

Wanlin Guo

State Key Laboratory of Mechanics and Control for Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016.

Corresponding Author: Wanlin Guo. Email: .

The International Conference on Computational & Experimental Engineering and Sciences 2019, 22(4), 184-186. https://doi.org/10.32604/icces.2019.04905

Abstract

The fracture mechanics theories have been developed actively for several decades, and have been successful for many specific engineering applications and serves as the fundamental for damage tolerant design of structures. In 1957, William and Irwin obtained the stress intensity factor K dominated solution of the singular stress and strain fields near crack tip in linear elastic plate, provided the theoretical basis for linear elastic fracture mechanics. In 1968, the famous J-integral dominated HRR solution for plane stress and plane strain cracked plates of power law hardening materials has long served as the fundamental of elastic-plastic fracture mechanics and similar solution has been developed for power law creeping cracked plates in 1980s. In 1986, Li and Wang solved the higher terms to the HRR solution and proposed that the J-dominated plane strain HRR solution is not enough for finite sized plates. Discussions about the higher order solutions widely attracted the attention of the fracture community in the world during 1990s and developed into constraint theories to consider the in-plane constraint effects. However, all the HRR solution based higher order solutions and constraint theories are mainly limited to two-dimensional cracked plates at the two limits of out-of-plane constraint T_z = σ_zz/σ_xx + σ_yy = 0 for plane stress and 0.5 for ideal plane strain states. In 1993, we developed the two parameter J-T_z dominated singularity solution for cracks in power law hardening materials under general out-of-plane constraints ranging from 0 to 0.5, filling the gap between the plane stress and plane strain states [1]. We have also developed the J-T_z solution to three parameter J-T_z-Q_T solutions to consider both the in-plane and out-of-plane constraints, and recently to C*-T_z-Q* solution for power law creeping solids [2-4].
Based on this three-dimensional (3D) theory, we have made great efforts in the past 20 years to bridge the gap for fracture and fatigue from laboratory standard specimens to complex engineering structures [5-12]. In this talking, we will address the advances in the following critical issues and introduce our most recent works along the line.
  1) From 2D fracture mechanics to 3D fracture mechanics;
  2) From tensile to mixed mode loadings;
  3) From static/toughness to fatigue/durability;
  4) From ambient to high temperature environments;
  5) From empirical design to predictive design;
  6) From continuum methodology to multiscale simulations.

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