Help for karamba units and stress results interpretation

Grasshopper Karamba3D
1

Hello everyone, I am currently working on a structural analysis using Karamba3D in
Rhino/Grasshopper, and I would like to clarify a few points regarding
units and stress visualization:

  1. Principal stresses interpretation:

Could you please confirm how Principal Stress 1 and Principal Stress 2
should be interpreted in shell results? Specifically, does Principal
Stress 1 always correspond to tension and Principal Stress 2 to
compression? Or should I consider compression the red values and
tension the blue ones in each scale, regardless of the Princiapl stress
shown?

  1. Legend units in Shell View:

When I visualize shell results (for instance, Principal Stress 1/2 or
Equivalent Stress) and attach the legend, the color scale shows units as
kN/cm², while my input loads are in kN/m² (as the Rhino model is
in meters).
Could you clarify which unit system the legend values actually
represent? Are those stresses truly expressed in kN/cm², or should they
be interpreted as kN/m² instead?

I would be very grateful if you could help me understand how to ensure
consistency between the model input units and the stress output shown in
the legends.

Thank you very much for your time and support.

2

Hello @Michele9,

ad 1.) Principal Stress 1 is the maximum in-plane stress, Principal Stress 2 is the minimum in-plane stress. So both can be positive or negative.

ad 2.) The legend output is in kN/cm² which is the customary unit for e.g. concrete structures.

– Clemens