I was wondering how to make my car stronger in beam like this one https://www.beamng.com/threads/nearly-indestructible-200bx.33007/
You could also change beamdeform and beamdamp values and introduce more beams to support weaker areas.
To beam deform "FLT_MAX" I don't know about beam spring, but that is beam that will not deform at least easily. I would think that beam strength might also accept "FLT_MAX" ? I would not touch spring, I don't know much about how that affect things.
To me it sounds to be something like that: beamStrenght Strength of the beam. How much force the beam can resist before breaking (N). https://wiki.beamng.com/JBeam_Reference#beams Spring just changes how much beam will stretch, breaking is defined by beamStrength and permanent deformation by beamDeform. So if one sets beamStrength and beamDeform both to "FLT_MAX" then it should be unbreakable. You could have very low beamSpring and it still would be unbreakable, just flexing more. That is how I understand it, but I'm not an expert.