What material are the pieces made out of? Wooden pieces (when properly dried) have a much larger ratio of elastic range to plastic range, which is probably desirable for toys (as you/your daughter would need lots of leverage to be able break the pieces and could effectively never bend them).
That's way more types of plastic than I expected. Still, most regular lego and duplo is indeed the same: ABS. But I didn't expect they'd have several different types of plastic just for different technic pieces.
Yes, I don't think they'll break either. I'm not exerting a strong force either.
It just makes me wonder whether the layout is "perfect" or there is some unwanted deviation from the "ideal" layout that is causing stress on the pieces. You know, how you can sort of force the pieces in a puzzle to fit together, but you know they are not meant to go that way? If you look at the top voted answer in the link, you'll notice someone does some maths and tells the asker "you have to add pieces here and here in order to reduce stress and be closer to the ideal shape".
I find it hard to explain in words, but hopefully you'll understand what I mean.
(Of course, this is not something I really worry about. It just makes me wonder.)
I'm also interested in knowing what the set of all possible layouts with zero stress are for a given bag of pieces. It feels like it might be an easier question to answer than what the article answers: trying to approximate, below a boundary of acceptable stress, a pre-existing shape with only certain pieces.
I think I would construct a tree of combinations of pieces, where each node of the tree was weighted with a vector of three elements: the X and Y position of the end of the piece relative to the start, and the angle of the track's direction at the end of the piece. Each subsequent piece added to the track (represented by a new layer of depth of the tree) would sum the previous weight vector. At any point in the tree where the vector sums to zero, you know you've completed a full loop and so terminate that branch of the tree there. After searching through the full factorial of the number of pieces you have, you can select all the zero-weight nodes to get the possible layouts. It seems as if the article uses abstract 'it turns left' and 'it turns right' pieces, rather than arbitrary sizes and angles, and doesn't use any tree-based brute-forcing to find possible answers.
