Robot Basic Build Guide

To choose materials to be used in light and stiff truss elements, consider the dashed guideline associated with constant E/ρ (labeled E/ρ = C). All the materials in the same straight line are equivalent, in other words, trusses of same weight made out of these materials would have the same stiffness. Now, draw parallel lines to this guideline. The higher the parallel line, the better will be the material. For instance, in the lowest guideline with constant E/ρ, we can see that plastified PVC is equivalent to cork. Going up to the next parallel E/ρ guideline, we reach the polyesters. The next parallel E/ρ guideline is a little below copper (Cu) alloys. A little above, note that, as expected, all steels, titanium (Ti), aluminum (Al) and magnesium (Mg) alloys are aligned, due to their E/ρ ≅ 25, as calculated before. The highest line with constant E/ρ in the figure goes through unidirectional carbon fibers (CFRP). A little further above we can see the infamous beryllium alloys (Be). This means that, to make a light and stiff truss, beryllium alloys would be better than CFRP, which is 77