Section 11.5.1. NASGRO Fracture Analysis Software
NASGRO was originally developed at NASA Johnson Space Center to
perform fracture control analysis on NASA space systems. Later, after the NASA/FAA/USAF
Aging Aircraft Program was formed and began supporting the development effort,
NASGRO was developed further for use in damage tolerance analysis of aircraft,
including that required for FAA certification.
The software is comprised of the following three modules:
- Life Assessment
- 2-D Boundary Element
Database of da/dN & fracture test results
NASFLA is part of the NASGRO 3.0 suite of programs Stress
Intensity Factor -These are computed for the crack geometry and loading chosen
from the NASFLA library of models, and displayed in tabular or graphical form.
NASBEM is part of the
NASGRO 3.0 suite of programs. It is a
two-dimensional boundary element program used to perform the following
Stress Intensity Factors - These can be calculated for
any geometry and loading. Tables of stress intensity factors and corresponding
crack lengths can be generated for use by the NASFLA module in performing life
Stress Fields - These can be calculated for any
collection of points in the two-dimensional uncracked object being modeled
including its boundary.
NASMAT is used to store, retrieve and curve fit crack growth
and fracture toughness data. It has a database containing over 9000 sets of
data. This includes over 3000 sets of fatigue crack growth data and over 6000
fracture toughness data points. These data can be searched, plotted, and fitted
to either the NASGRO crack growth rate equation or a user specified growth rate
equation, or they can be entered into a growth rate table.