@EnergyNumbers I get the rules about shopping, but i'm not asking for a recommendation or other subjective answer here.(ie. in the main question) I need a sensor with certain capabilities and i'm asking if anyone knows if there's such a sensor available.

So to simplify, create larger cross members. That's a good approach for me I think. The shape of the construction isn't changed then, only the corss members' diameter. It's a relatively small and simple change it seems, so it's fine for a first excercise. I'll do that.

I agree that keeping it original is better, I wouldn't introduce dramatic modifications in the chassis even if they'd have good potential. But the chassis itself is rotten and rusted through, so it needs rebuilding anyway. I might as well add some minor mods to increase stiffness here and there while i'm at it. That is, if that'd show to improve performance. If it doesn't, or if i'm not sure I'll just leave the chassis completely original, and the excercise is still a success.

You'd be 100% right if I were to actually modify the chassis with the construction, but it's just a FEM excercise, not even a serious experiment. I agree my approach isn't very scientific, but my goal was to come up with some kind of construction that one could expect would make the chassis more torsion resistant. Maybe that wouldn't even improve driveability, but that's not relevant. It'd be nice if it showed to be, so that i could use that information while rebuilding my chassis, but it's not necessary.

@alephzero So you say that i'd get ideas about how to improve the chassis, once i've found the weak points after an analysis of the original chassis? That'd be a good strategy, but I have to do the proposal of my idea before I can start the assignment, so that won't be possible.. I was hoping for a simple idea to further investigate, like a triangluar bridge or something. Regarding the assignment, costs and feasability are no issue, because it's only an excercise. It'd an issue if i'd decide to really implement the improvement in the frame, but i think i'll edit that out of the question.

@Wasabi I have to do FEM calculations on the original frame, and on the improved frame. I have to make an improvement to the frame, so hence my question; 'How could i best improve the frame?'