def Problem8_51():
Pg = 6 # MPa
A = 20
B = 20
d = 12
Sp = 650
D = 1.5*d
l = A + B
H = 10.8
# L = H + l + 2*p
L = 60
Lt = 2*d + 6
ld = L - Lt
lt = l - ld
Ad = np.pi/4*d**2 #Table 8-7
At = 84.3 #Table 8-1
kb = Ad*At*207/(Ad*lt + At*ld)
kSteel = Screw.SpringRate(207, d, D, A)
kCastIron = Screw.SpringRate(100, d, D, B)
kM = 1/(1/kSteel + 1/kCastIron)
C = kb/(kb + kM)
Fi = 0.75*At*Sp
P = Pg*np.pi/4*150**2/10/1000
sigmaI = Fi/At
sigmaA = C*P*10**3/(2*At)
sigmaM = sigmaA + sigmaI
Sut = 900
Se = 140
print(Screw.Goodman(Se, Sut, sigmaI, sigmaA, 0))
print(Screw.Gerber(Se, Sut, sigmaI, sigmaA))
print(Screw.ASMEElliptic(Se, Sut, Sp, sigmaI, sigmaA))
# Begin problem 8 - 55
sigmaI = Fi / At
sigmaA = C*(P - P/2)*10**3/(2*At)
sigmaM = sigmaA + sigmaI
print('Test', Screw.Goodman(Se, Sut, 487.5, 3.675, 498.5))
print(Screw.Goodman(Se, Sut, sigmaI, sigmaA, sigmaM))
def Problem5():
"""WRONG
Given a non-permanent bolted joint with a bolt stiffness
of 2.4 Mlbf/in and a member stiffness of 3.5 Mlbf/in that is
supporting a tensile load that fluctuates repeatedly between
0 and 2.1 kip, what is the factor of safety against fatigue
failure if one, 5/16”-18, SAE grade 8 bolt is used? Use Goodman
theory if needed."""
kb = 2400 #klbf/in
km = 3500 #klbf/in
P = 2.1 #kip
Sy = 130 #kpsi
d = 5 / 16
At = 0.0524 #in^2
Fi = 0.75 * At * Sy
C = kb / (kb + km)
sigmaI = Fi / At
sigmaA = C * P / (2 * At)
sigmaM = sigmaA + sigmaI
Sut = 150 #kpsi Table 8-9
Se = 23.2 #kpsi Table 8-17
n = Screw.Goodman(Se, Sut, sigmaI, sigmaA, sigmaM)
print(n)