Originally Posted by
peteeng
Hi Sash - That's 60N/um that's quite stiff but you have to add in the rest of the structure yet. Do you have a target static stiffness in mind? Re preload in compression... Concrete is very poor in tension so concrete beams and panels are preloaded on the compression side to "force" the structure more to the compression side to keep the concrete from going into tension once loaded. Generally epoxy is about 10x stronger then concrete so this tensile strength issue is not a problem. Plus machines being so stiff have very low stresses in them. If you have to preload the structure your probably way way off where it should be. Unless you get into tensegrity structures then they have to be in tension....Peter