How to write the statement for MAX and MIN safety margin?

[alin09]

How to write NASTRAN statement for output of safety margin:
MAXMIN (DEF) TTTT (BEAM,10) MAXALG(10) MINALG(10)?

I know the how to write the ourput for stress and forces but don't know which word in NASTRAN is used for safety margin (replacing TTTT in the above statement). I tried to find it in the manual but could not.

Thanks!

 

[BlasMolero]

Dear alin09,

Conventions for BEAM elements:
• M.S.-T: Minimum margin-of-safety in tension.
• M.S.-C: Minimum margin-of-safety in compression.
• Minimum M.S. found over entire length of element

Definition of Margin-of-Safety (M.S.):
======================================
The M.S. in tension is: M.S.–T = (ST / S-MAX) – 1.0, where ST is the tension allowable given on the MAT1 entry and S-MAX is the maximum stress given in the output, S-MAX = max (SA-MAX, SB-MAX). M.S. in tension is computed and printed if and only if ST is greater than zero and S-MAX is greater than zero.

The M.S. in compression is: M.S.-C = (–SC / S-MIN) - 1.0, where SC is compression allowable given on the MAT1 card and S-MIN is the minimum stress given in the output, S-MIN = min (SA-MIN, SB-MIN). M.S. in compression is computed and printed if and only if SC is greater than zero and S-MIN is less than zero.

The output I have using FEMAP & NX NASTRAN 7.0 is the following:
S T R E S S E S I N B E A M E L E M E N T S ( C B E A M )
STAT DIST/
ELEMENT-ID GRID LENGTH SXC SXD SXE SXF S-MAX S-MIN M.S.-T M.S.-C
0 1
1 0.000 -4.220390E+03 -4.220390E+03 4.220390E+03 4.220390E+03 4.220390E+03 -4.220390E+03 3.7E+00 6.1E+00
2 1.000 -3.798351E+03 -3.798351E+03 3.798351E+03 3.798351E+03 3.798351E+03 -3.798351E+03

Best regards,
Blas.

 

[alin09]

Blas,

Thanks for the reply.
I know the meaning of margin of safety and how to calculate. But I don't know how I can get the first 10 maximum and minimum values of margin of safety by using the statement MAXMIN (DEF) TTTT (BEAM,10) MAXALG(10) MINALG(10) in NASTRAN input file? What do I use to for "TTTT" to represent margin of saftey?