def test_mass_spokes_only():
'Check that spoke masses are correctly calculated'
w = BicycleWheel()
w.hub = Hub(diameter=0.050, width=0.05)
w.rim = Rim(radius=0.3,
area=100e-6,
I_lat=200. / 69e9,
I_rad=100. / 69e9,
J_tor=25. / 26e9,
I_warp=0.0,
young_mod=69e9,
shear_mod=26e9)
w.lace_radial(n_spokes=36,
diameter=1.8e-3,
young_mod=210e9,
offset=0.,
density=1.0)
# Calculate mass of a single spoke
m_spk = np.hypot(0.3 - 0.025, 0.025) * np.pi / 4 * (1.8e-3)**2 * 1.0
# Should return a warning that the rim density is not specified
with pytest.warns(UserWarning):
m_wheel = w.calc_mass()
assert np.allclose(m_wheel, 36. * m_spk)
def test_mass_rim_only():
'Check that wheel mass returns rim mass if no spoke density is given'
w = BicycleWheel()
w.hub = Hub(diameter=0.050, width=0.05)
w.rim = Rim(radius=0.3,
area=100e-6,
I_lat=200. / 69e9,
I_rad=100. / 69e9,
J_tor=25. / 26e9,
I_warp=0.0,
young_mod=69e9,
shear_mod=26e9,
density=1.)
w.lace_cross(n_spokes=36,
n_cross=3,
diameter=1.8e-3,
young_mod=210e9,
offset=0.)
# Should return a warning that some spoke densities are not specified
with pytest.warns(UserWarning):
m_wheel = w.calc_mass()
assert np.allclose(m_wheel, 2 * np.pi * 0.3 * 100e-6)
def test_I_wheel_less_than_max():
'Check that rotational inertia is less than theoretical maximum'
w = BicycleWheel()
w.hub = Hub(diameter=0.050, width=0.05)
w.rim = Rim(radius=0.3, area=100e-6,
J_tor=25./26e9, I_lat=200./69e9, I_rad=100./69e9, I_warp=0.0,
young_mod=69e9, shear_mod=26e9, density=1.0)
w.lace_radial(n_spokes=36, diameter=1.8e-3, young_mod=210e9, offset=0., density=1.0)
I_wheel = w.calc_rot_inertia()
assert I_wheel < w.calc_mass()*w.rim.radius**2
def test_mass_rim_only():
'Check that wheel mass returns rim mass if no spoke density is given'
w = BicycleWheel()
w.hub = Hub(diameter=0.050, width=0.05)
w.rim = Rim(radius=0.3, area=100e-6,
I_lat=200./69e9, I_rad=100./69e9, J_tor=25./26e9, I_warp=0.0,
young_mod=69e9, shear_mod=26e9, density=1.)
w.lace_cross(n_spokes=36, n_cross=3, diameter=1.8e-3, young_mod=210e9, offset=0.)
# Should return a warning that some spoke densities are not specified
with pytest.warns(UserWarning):
m_wheel = w.calc_mass()
assert np.allclose(m_wheel, 2*np.pi*0.3*100e-6)
def test_mass_spokes_only():
'Check that spoke masses are correctly calculated'
w = BicycleWheel()
w.hub = Hub(diameter=0.050, width=0.05)
w.rim = Rim(radius=0.3, area=100e-6,
I_lat=200./69e9, I_rad=100./69e9, J_tor=25./26e9, I_warp=0.0,
young_mod=69e9, shear_mod=26e9)
w.lace_radial(n_spokes=36, diameter=1.8e-3, young_mod=210e9, offset=0., density=1.0)
# Calculate mass of a single spoke
m_spk = np.hypot(0.3 - 0.025, 0.025) * np.pi/4*(1.8e-3)**2 * 1.0
# Should return a warning that the rim density is not specified
with pytest.warns(UserWarning):
m_wheel = w.calc_mass()
assert np.allclose(m_wheel, 36.*m_spk)
def test_I_wheel_less_than_max():
'Check that rotational inertia is less than theoretical maximum'
w = BicycleWheel()
w.hub = Hub(diameter=0.050, width=0.05)
w.rim = Rim(radius=0.3,
area=100e-6,
J_tor=25. / 26e9,
I_lat=200. / 69e9,
I_rad=100. / 69e9,
I_warp=0.0,
young_mod=69e9,
shear_mod=26e9,
density=1.0)
w.lace_radial(n_spokes=36,
diameter=1.8e-3,
young_mod=210e9,
offset=0.,
density=1.0)
I_wheel = w.calc_rot_inertia()
assert I_wheel < w.calc_mass() * w.rim.radius**2