def spar_crit_stress(y): #ks needs to be determined manually
if y <= 10:
ks = 9.8
if 10 < y <= 20:
ks = 9.5
if y > 20:
ks = 9.5
b = (points[1][1] - points[2][1]) * chord_function(y)
stress = (((pi**2) * ks * E) / (12 * (1 - (pois**2)))) * ((t / b)**2)
return stress
def string_stress_normal(y):
M_z = z_moment(y)
M_x = x_moment(y)
I = inertia(y)
I_zz = I[1]
I_xx = I[0]
I_xz = 0
centroid = get_centroid(y)
wingbox_point = [i * chord_function(y) for i in wingbox_points[1]]
x = wingbox_point[0] - centroid[0]
z = wingbox_point[1] - centroid[1]
sigma = ((((M_x * I_zz) - (M_z * I_xz)) * z) +
(((M_z * I_xx) - (M_x * I_xz)) * x)) / (((I_xx * I_zz) - I_xz**2))
return sigma
def dtheta_multi(y):
chord = chord_function(y)
matrix = np.array(
[[2 * Area_first * chord * chord, 2 * Area_second * chord * chord, 0],
[(((((a_one + a_two) * chord) / t2) + (b_one * chord / t1) +
(b_three * chord / t3)) / (2 * Area_first * chord * chord * G)),
-1 * ((b_three * chord / t3) / (2 * Area_first * chord * chord * G)),
-1],
[
-1 * ((b_three * chord / t3) /
(2 * Area_second * chord * chord * G)),
(((((c_one + c_two) * chord / t2) + (b_two * chord / t1) +
(b_three * chord / t3)) /
(2 * Area_second * chord * chord * G))), -1
]])
solution_vector = np.array([torsion(y), 0, 0])
q1, q2, dtheta = np.linalg.solve(matrix, solution_vector)
return q1, q2, dtheta
def single_cell_stiffness(y):
chord = chord_function(y)
line_int = ((a_one + c_one + a_two + c_two) * chord) / t2 + (
(b_one + b_two) * chord) / t1
return (4 * ((Area_second * chord * chord)**2)) / line_int
def stringer_spacing_bottom(y):
if y <= bot_lim1:
spacing = (sqrt((points[1][0] - points[0][0])**2 + (points[1][1] - points[0][1])**2) * chord_function(y)) / (bot_num_1+2)
if bot_lim1 < y <= bot_lim2:
spacing = (sqrt((points[1][0] - points[0][0])**2 + (points[1][1] - points[0][1])**2) * chord_function(y)) / (bot_num_2+1)
else:
spacing = (sqrt((points[1][0] - points[0][0])**2 + (points[1][1] - points[0][1])**2) * chord_function(y)) / (bot_num_3+1)
return spacing