Originally Posted by
Andrew R Stewart
.....We are in the same area WRT understanding properties. I just dislike the "Al Is stiff" misnomer. To me this is marketing. I now know you don't think so. Here's hoping that our readers also know better. Andy.
I take this one step farther and find fault with ALL of the general characterizations of properties of the various materials.
Yes, of course materials have individual properties, such as density, ductility, fatigue resistance, and so on.
But mechanical or riding properties of structures made from these materials are just as dependent on the physical configuration, ie. tube diameter & wall thickness, along with construction method, temper (where applicable), and other human controlled aspects.
So, in the end, it's not as much about the material itself, but the designers thinking in choosing it and the overall design objectives.
For example, it's not that aluminum frame are inherently stiff, but that the material was chosen, because it was possible to use larger diameter tubes, and benefit from their higher moment of inertia, without a weight penalty.