def setup(self, b, cave, tau, N=5):
self.N = N
rho_cfrp = Variable("\\rho_{CFRP}", 1.6, "g/cm^3", "density of CFRP")
E = Variable("E", 2e7, "psi", "Youngs modulus of CF")
with Vectorize(self.N - 1):
d = Variable("d", "in", "spar diameter")
I = Variable("I", "m^4", "spar x moment of inertia")
Sy = Variable("S_y", "m**3", "section modulous")
A = Variable("A", "in**2", "spar cross sectional area")
dm = Variable("dm", "kg", "segment spar mass")
W = Variable("W", "lbf", "tube spar weight")
g = Variable("g", 9.81, "m/s**2", "gravitational constant")
constraints = [
dm >= rho_cfrp * A * b / (N - 1), W >= 2 * dm.sum() * g,
cave * tau >= d, 4 * I**2 / A**2 / (d / 2)**2 + A / pi <=
(d / 2)**2, Sy * (d / 2) <= I, E == E
]
return constraints
