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Composite - Margin of Safety

Valued Contributor
Valued Contributor

I am trying to plot the margin of safety for a composite laminate. I have created an envelope case that combines the major pricipal stresses of all plies in the laminate.

 

Then I have tried to use the calculate function on the envelope case to determine the margin of safety.

 

I am using the following equation for the calculate function which basically is the following equation:

MS = (Material Allowable/Stress)-1.

 

(MAT(MLAM(PID(!i); PLYID);52)/(VEC(3;90000000;!i))-1)

 

I was wondering how can I modify the equation so that the Margin of Safety equation takes into account all the plies and gives me a margin of safety.

 

I was trying to use the equation provided here; however for laminates the function "MID(propID)" does not work (http://mechanicalengineeringblog.tumblr.com/post/117691398404/margin-of-safety-calculation-with-fema...).

 

Any help is appreciated.

 

Regards,

 

Saptarshi