Hi,
I am having trouble with the 3D truss analysis calculator. I am inputting four restraints that are only in the vertical Y-direction, and it is returning non-zero reaction force values for the X and Z directions. What might be going wrong?
Hi Aidan,
I looked briefly at your model - the main issue I notice (not to say there are not any other ‘hidden’ problems) is that the model does not contain any cross-members as you look ‘down’ through the centre of the truss…i.e. if you were to look through the middle of the truss from one end to the other. As a result, the model, when considered purely as a pin-jointed structure, with no moment resisting connections, is not stable. This is most likely why you’re seeing results that don’t make any sense.
Put another way, when you look at a cross-section of your truss, it is a quadrilateral (square in your case i think) - this should be triangulated - otherwise you need more elaborate solver that can take moment connections into account. We cover this here, but I don’t have a ‘ready-made’ solver online for it.
Hope that helps.
Seán