simple case of high strain rate effect

To observe the damage caused by dynamic or high strain rate impact on a material we use the stapler as an example. Take about 20 sheets of 20lb paper (usual printer paper) and try to staple them slowed as you would when you have 2 or 3 sheets. Depending on the quality of pins you often end up with a bent and twisted pin. If you try again by the forcing the stapler go faster you might actually end up sending the pin properly as you would want. The difference is primarily a strain rate effect. A similar but different loading was the case with columbia disaster. Typically metals are much more stiffer under impact and high strain rate loading. The dynamic case is well known. The dynamic fracture toughness is higher compared to toughness under static or quasi-static loading.