Rankine-Gordon formula which covers all cases of struts, is
where notation are as usual
1
P = \(\rm\frac{fcA}{1+\left(\frac{a}{k}\right)^2 l}\)
2
P = \(\rm\frac{fcA}{1+a\left(\frac{l^2}{k^2}\right)}\)
3
P = \(\rm\frac{fcA}{k^2+a^2l^2}\)
4
P = \(\rm\frac{fcA}{1+\frac{a^2l}{k^2}}\)