Possible issue with spring restrain

[linokl]

Hi Craig,

I am not sure if I am doing everything right but I have run into a bug I think. The analysis is crashing when I am using rotational spring restrain.

The arrangement is as below. Cantilever beam with a spring at the free end resisting rotation. I am not very familiar with this kind of restraint so not 100% sure it is a bug or I am doing something wrong.

I recreated the issue in one of your example beam problem and it is throwing an error. Please see the code below.

Example of a simply supported beam with a uniform distributed load.

Units used in this example are inches and kips

This example does not use load combinations. The program will create a default load combindation called 'Combo 1'

Import FEModel3D from PyNite

from PyNite import FEModel3D

Create a new finite element model

SimpleBeam = FEModel3D()

Add nodes (14 ft = 168 in apart)

SimpleBeam.add_node('N1', 0, 0, 0) SimpleBeam.add_node('N2', 168, 0, 0)

Add a beam with the following properties:

E = 29000 ksi, G = 11400 ksi, Iy = 100 in^4, Iz = 150 in^4, J = 250 in^4, A = 20 in^2

SimpleBeam.add_member('M1', 'N1', 'N2', 29000, 11400, 100, 150, 250, 20)

Provide simple supports

SimpleBeam.def_support('N1', True, True, True, True, True, True)

SimpleBeam.def_support_spring('N2', 'RZ', 1, None)

Add a uniform load of 200 lbs/ft to the beam

SimpleBeam.add_member_dist_load('M1', 'Fy', -200/1000/12, -200/1000/12, 0, 168)

Alternatively the following line would do apply the load to the full length of the member as well

SimpleBeam.add_member_dist_load('M1', 'Fy', 200/1000/12, 200/1000/12)

Analyze the beam

SimpleBeam.analyze()

Print the shear, moment, and deflection diagrams

SimpleBeam.Members['M1'].plot_shear('Fy') SimpleBeam.Members['M1'].plot_moment('Mz') SimpleBeam.Members['M1'].plot_deflection('dy')

Print reactions at each end of the beam

print('Left Support Reaction:', SimpleBeam.Nodes['N1'].RxnFY, 'kip') print('Right Support Reacton:', SimpleBeam.Nodes['N2'].RxnFY, 'kip')

Render the deformed shape of the beam magnified 100 times, with a text height of 5 inches

from PyNite import Visualization Visualization.render_model(SimpleBeam, annotation_size=5, deformed_shape=True, deformed_scale=100, render_loads=True)

Kind Regards Lino

[JWock82]

Thanks for reporting this Lino. I'll have a look at this as soon as I get an opportunity. There's no reason this shouldn't be working. I have not used rotational springs personally, so I can see why this one may have slipped through unnoticed. It should be an easy bug to fix.

[JWock82]

This issue has been resolved. Please try your code again and let me know if you are still having any problems.

[linokl]

Thanks Craig. I will check it. If you want to take the Frame3D module for a spin the access code is "Frame3D_mainP"

[linokl]

The issue is resolved now. The analysis is working fine with spring