# stress intensity factor

## Stress intensity factor

Hi I have long been looking for a clear way of defining stress intensity factors. Apart from the usual bookinsh definitions such as "strength of singularity" "state of stress". Of course I could convince myself by relating SIF with Strain Energy Release Rate (G) as 'G' has a more convincing physical meaning explained through the creating of new surfaces. This kind of gives the feeling that 'K' is a derived quantity in the field of fracture mechanics.

So is there a better way of explaining SIF without having to go through 'G'.

## ABAQUS - Stress Intensity Factor for Single Radial Crack in Thick Walled Cylinder

Hi,

I am trying to analyze the stress intensity factor (SIF) using contour integral of a 2D thick walled cylinder under plane stress with different wall ratios under internal pressure loading only and a single radial crack of varying length in Abaqus.

The wall ratio (inner & outer radius) I am interested in modelling is of ratio 6 (i.e. for inner radius of 1, outer radius is 6).

I have modelled ratios from 1-6 with crack length varying from 0.1-0.9 of the wall thickness. (i.e. for ratio 3, the wall thickness is 2, hence the crack varies from 0.1-0.9 x 2).

## How to calculate Stress intensity factor through FE programming?

Dear all,

I need to calculate SIF through a FEM program by writing some line of codes. The problem is that I wasn't able to find a reference contains straightforward formulation and procedure for this. Can anybody help me please with this issue?

Cordially,

## Discussion of fracture paper #6 - Stress intensity factor for steep yield distribution

T. Yasuoka, Y. Mizutani, A. Todoroki: Applicable limit of the stress intensity factor for steep yield strength distribution, Engineering Fracture Mechanics, 2013, Vol. 110, pp. 1-11.

To the discussion

## What is the crack-tip stress intensity factor of an embedded crack under mode II shear?

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Hi,

From textbook of fracture mechanics, we know that for an embedded crack subjected to mode I stress state, KI=(2/π)σ√πa, while 2a is the crack size.

But for a embedded crack subjected to a pure shear stress τ, what is the stress intensity factor at the crack-tip?

Thank you

Ruitao

## prediction of crack path which is subjected to stress gradient and biaxial load.

Dear all.

I'm currently doing some research concerning crack path prediction in brittle thin film.

But I'm struggled to find efficient way to do it.

In reality my case: stress is higly confined within semi infinite narrow rectangular strip patten and out of this rectangular, stress is very low or near 0 compared to stress within the pattern. Crack starts from left side end and propagates within pattern toward right end side of pattern. Crack show wavy propagation behavior with regular period and amplitude.

## Why does the overshoot occur in Dynamic Stress Intensity Factor

I wanted to get some insight in the transient stress intensity factor (SIF).

In the time history, we notice there is an overshoot (~27%)  from the
steady state SIF for a fixed (not propagating crack). I found the
overshoot occurs at the time when the reflected wave from the opposite
crack-tip comes back to the first crack tip. I wanted to know why this
overshoot occurs, what is the physical explanation?

Sandip Haldar

## Spacing effect on dislocation injection from sharp features in strained silicon structures

In practice, the SiN stripes or pads are periodically patterned on silicon, so the spacing effect on dislocation injection from sharp features deserves attention. As in Figure 1, the SiN stripes with residue stress, of width L and thickness h, are periodically patterned with spacing S. In the numerical calculation, we take shear modulus and Poisson’s ratio of Si3N4 to be 54.3 GPa and 0.27, and those of silicon 68.1GPa and 0.22, the same as in Ref.[1].