bar_mass[-1] = np.array([mass_matrix.compute_mass_matrix (length = bar_lengths.ravel()[i], density = density_2, sigma=0.)[0] ]) else: bar_mass = np.array ([ mass_matrix.compute_mass_matrix (length = bar_lengths.ravel()[i], density = density_1, sigma=None)[0] for i in range (B.shape[0]) ]) #compute external forces (gravity :) external_forces_1 = np.zeros(N.shape) if default_gravity == True: force_distribution_gravity = lambda x: (0,0,-9.81) # Earth's gravity else: force_distribution_gravity = lambda x: (0,0,-gravity) # Titan's Gravity for i in xrange(B.shape[0]): #this is pretty complicated for something really simple... if i<(B.shape[0]-1): f1_1,f2_1 = mass_matrix.compute_consistent_nodal_forces_vector(length=bar_lengths.ravel()[i],density=density_1,force_distribution=force_distribution_gravity) from_ = B[i].argmin() to_ = B[i].argmax() external_forces_1[from_] = f1_1 external_forces_1[to_] = f2_1 else: f1_1,f2_1 = mass_matrix.compute_consistent_nodal_forces_vector(length=bar_lengths.ravel()[i],density=density_2,force_distribution=force_distribution_gravity) from_ = B[i].argmin() to_ = B[i].argmax() external_forces_1[from_] = f1_1 external_forces_1[to_] = f2_1 print 'Gravity Forces' print external_forces_1 external_forces_1_func = lambda t: (1*t*external_forces_1) #gravity is applied
#computed center of mass (to decouple rotational and translational eq. of motion) bar_sigma = [1,0,None,None,None,1] bar_massmatrix = [] #strut mass matrices for i in xrange(ico.B.shape[0]): b, bar_sigma[i], dummy = mass_matrix.compute_mass_matrix(length = strut_lengths[i], sigma=bar_sigma[i], density= lambda x: 0.5*ico.bar_mass[i]*(strut_lengths[i]/ico.bar_lengths[i,0] if x<ico.bar_lengths[i,0]/strut_lengths[i] else strut_lengths[i]/ico.bar_lengths[i,1])) bar_massmatrix.append(b) bar_massmatrix = np.array(bar_massmatrix) #compute nodal forces due to gravity external_forces = np.zeros(ico.N.shape) force_distribution = lambda x: (0,0,-9.81) for i in xrange(ico.B.shape[0]): #this is pretty complicated for something really simple... f0,f1 = mass_matrix.compute_consistent_nodal_forces_vector(length=strut_lengths[i],density=lambda x: 0.5*ico.bar_mass[i]*(strut_lengths[i]/ico.bar_lengths[i,0] if x<ico.bar_lengths[i,0]/strut_lengths[i] else strut_lengths[i]/ico.bar_lengths[i,1]),force_distribution=force_distribution) from_ = ico.B[i].argmin() to_ = ico.B[i].argmax() external_forces[from_] = f0 external_forces[to_] = f1 #these springs show up blue in the GUI (easier to spot the actuators) #ico.spring_ tagged_springs = np.zeros(ico.C.shape[0]) tagged_springs[-6:] = 1 constrained_nodes[:] = 0 constrained_nodes[1] = 1 constrained_nodes[2] = 1 constrained_nodes[11] = 1
for i in range(B.shape[0])
])
#compute external forces (gravity :)
external_forces_1 = np.zeros(N.shape)
if default_gravity == True:
force_distribution_gravity = lambda x: (0, 0, -9.81) # Earth's gravity
else:
force_distribution_gravity = lambda x: (0, 0, -gravity) # Titan's Gravity
for i in xrange(B.shape[0]):
#this is pretty complicated for something really simple...
if i < (B.shape[0] - 1):
f1_1, f2_1 = mass_matrix.compute_consistent_nodal_forces_vector(
length=bar_lengths.ravel()[i],
density=density_1,
force_distribution=force_distribution_gravity)
from_ = B[i].argmin()
to_ = B[i].argmax()
external_forces_1[from_] = f1_1
external_forces_1[to_] = f2_1
else:
f1_1, f2_1 = mass_matrix.compute_consistent_nodal_forces_vector(
length=bar_lengths.ravel()[i],
density=density_2,
force_distribution=force_distribution_gravity)
from_ = B[i].argmin()
to_ = B[i].argmax()
external_forces_1[from_] = f1_1
external_forces_1[to_] = f2_1
