arekbed
posted this
16 November 2018

So, maybe I explain my situation. I create several experimental tests to get information about the number of cycles to crack initiation in compressor blade (crack length equal to 1 mm). After this, I try to compare numerical and experimental results. To prepare strain-life analysis, I designate data (based on models: Mansons, Mitchell, Roessle-Fatemi, Baumell-Seger, Ong, etc.) to Manson-Coffin-Basquin equation and data connected to work hardening. After loading on the blade I found information about stress distribution in the top of the notch. Based on stress, I try to achieve information about fatigue life.

My supervisor told me (and show in MSC Fatigue documentation) that numerical results of fatigue life correspond to crack with 1 mm, and suggested me to find information about to what kind of damage correspond the numerical result of e-N analysis or maybe exist some kind of criterion what is implemented in ansys code.

So my question is: what kind of damage I theoretically will have in my element after the obtained number of load cycles (crack appearance, crack with 1 mm length or total failure - dividing to two separate elements)?

We need to remember, a numerical model of material is based on some assumptions. Additionally, we need to remember about that blade have complex geometry and material parameters inside the blade are different than in the surface (because of treatment during production).

Resources what I found above do not give me information what I'm looking for. Part of them I known for long.

I'm appreciated that you try to help me and I hope so with your help I will find informations to finish my PhD work.

with best regards,

Arek