The experimental determination of fracture mechanical properties of interface cracks is a substantial task for the design for reliability of electronic packages. As interface cracks are dominated by a mode mix between tension and shear mode (crack driving modes I and II) a mixed mode bending method was developed to adjust the ratio of the two modes (mode mixity). For a correct extraction of an ...

The creep crack problems in damaged materials under mixed mode loading (Mode I and Mode II loading) in the framework of creep-damage coupled formulation are considered. The class of the self-similar solutions to the plane creep crack problems in a damaged medium under mixed-mode loading is given. With the similarity variable and the self-similar representation of the solution for a power-law cr...

Some Characteristic behavior of the T e (Atluri, Nishioka and Nakagaki (1984)) is identi®ed in this paper through an extensive numerical study. T e is a near tip contour integral and has been known to measure the magnitude of singular deformation ®eld at crack tip for arbitrary material models. In this paper, T e is found to behave quite differently for different choices of near tip integral co...

http://dx.doi.org/10.1016/j.actamat.2015.07.022 1359-6454/ 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Materials Science & Engineering, University of California, Berkeley, CA 94720, USA. E-mail address: [email protected] (R.O. Ritchie). 1 Intrinsic toughening mechanisms operate ahead of the crack tip to resistance to microst...

Water molecules play a fundamental role in the physics of slow crack propagation in glasses. It is commonly understood that, during stress-corrosion, water molecules that move in the crack cavity effectively reduce the bond strength at the strained crack tip and, thus, support crack propagation. Yet the details of the environmental condition at the crack tip in moist air are not well determined...

A B S TR AC T This paper presents an incremental elastic-plastic finite element solution to the problem of small scale yieldmg near a crack in plane strain for a non-hardening material. Emphasis is placed on the design of finite elements which allow accurate reproduction, m a numerical solution, of the detailed structure of the near crack tip stress and strain fields, as understood from previou...

Age-hardenable aluminum alloys used in aerospace structures are susceptible to environment assisted fatigue crack propagation (EFCP), limiting component durability and safety. The objective is to quantitatively understand EFCP and its inhibition for important aerospace alloys: 7075-T651 (Al-Zn-Cu-Mg), C433-T3 (Al-Cu-Mg), and C47A-T86 (AlCu-Li). EFCP is understood through the hydrogen embrittlem...

To better understand the ductile versus brittle fracture behavior of crystalline materials, attention should be directed towards physically realistic crack geometries. Currently, continuum models of ductile versus brittle behavior are typically based on the analysis of a pre-existing sharp crack in order to use analytical solutions for the stress 8elds around the crack tip. This paper examines ...

This paper presents a finite element formulation of elasticity to model elastic fracture in composites with long aligned fibers. We have employed a B-bar type approach which is applicable to compressible as well as nearly incompressible material systems. An energy approach is undertaken to evaluate the stress intensity factor at the crack tip. The effects of strong intact bridging fibers, fiber...

A line integral is exhibited which has the same value for all paths surrounding the tip of a notch in the two-dimensional strain field of an elastic or deformation-type elastic-plastic material. Appropriate integration path' choices serye bOlh to relate Ihe integral to the near tip deformatiot~s and, in many cases. to permit its direct e:tlalutllion. This (l.t'eraged measure of the near tip fie...