c=1/Sqrt[2]
q={0,-300.}

G={{-c,-1},{c,0}}
MatrixForm[G]
IG=Inverse[G]
s=-IG.q
Astresslimit=s/24
Abucklinglimit=Sqrt[300.*4*100^2/(Pi*21000)]
NMinimize[{A1/c+A2, A1≥17.6777,A2≥12.5},{A1,A2}]
NMinimize[{A1/c+A2,A1≥17.6777,A2≥13.4867},{A1,A2}]