Model Re-Analysis

[bjhowie]

Model Re-Analysis

[JWock82]

Iy is for weak axis bending. Iz is for strong axis bending.

[bjhowie]

I've tried changing Iy, Iz and E. No change.

There's no stiffness matrix buffer or results set that i need to manually clear before re-running?

[JWock82]

I'll have a closer look at this when I get a moment - it may be a bug. You should be able to swap out "I" values and rerun. It's been a while, but I believe I set up the stiffness matrix to re-assemble anytime you invoke the analyze command.

[JWock82]

I've experimented with it and it seams to be working for me. Here's a simple working example:

from PyNite import FEModel3D

beam = FEModel3D()

# Define the nodes
beam.add_node('N1', 0, 0, 0)
beam.add_node('N2', 10*12, 0, 0)
beam.add_node('N3', 20*12, 0, 0)

# Define the supports
beam.def_support('N1', True, True, True, True, False, False)
beam.def_support('N2', True, True, True, False, False, False)
beam.def_support('N3', True, True, True, False, False, False)

# Create the beam member
Iz = 24*30**2/12
Iy = 30*24**3/12
J = Iz + Iy
E = 57*(4500)**0.5
G = 0.4*E
A = 24*30

beam.add_member('M1', 'N1', 'N3', E, G, Iy, Iz, J, A)

# Add a member load
w = 0.100*(10*12)
beam.add_member_dist_load('M1', 'FY', w, w)

# Analyze the model
beam.analyze()

# Calculate deflection
d1 = beam.Members['M1'].min_deflection('dy')

# Change the moment of inertia to account for cracking
Iz = 0.35*Iz
beam.Members['M1'].Iz = Iz

# Reanalyze the model
beam.analyze()

# Recalculate deflection
d2 = beam.Members['M1'].min_deflection('dy')

# Compare deflection values
print(d1, d2)

[bjhowie]

So as it turns out, I was using an older version. I upgraded and it all works fine now.

Sorry about that. Probbaly the first thing i should have done!