# Petrersons Notch Sensitivity Calculation.xls

(4/6)

### Description

Purpose of calculation
Calculate notch sensitivity factor for steel and aluminium.

Calculation Reference
Peterson's Stress Concentration Factors.

Calculation Validation
Formulae checked graphically and using the XLC addin.

Any Consistent Calculation Units

Two tensile test samples same net area over the critical section. One has a groove (notch) the other does not. The load at failure for the notched specimen is less than the un-notched specimen. Curve 1 shows stress distribution when loads are low. The maximum stress to nominal stress is the theoretical elastic stress concentration factor Kt.

Brittle materials behave like curve 2 and less brittle like curve 3.
The maximum stress to nominal stress is the theoretical elastic stress concentration factor Ke = Kt. At failure the maximum stress is tensile stress of the material. Notch sensitivity factor is close to 1.

Ductile materials behave like curve 3 and very ductile like curve 4.
The actual maximum stress to nominal stress is the effective stress concentration factor Ke =P/P'. At failure the maximum stress is just a little higher than yield. Notch sensitivity factor is small.

Calculation Reference

Peterson's Stress Concentration Factors

Fatigue Analysis

Fundamentals of Fatigue

### Calculation Preview

20 Jul 2011
File Size: 158.00 Kb