a cupping test in which a piece of sheet metal, restrained except at the center, is deformed by a standard steel ball until fracture occurs; the height of the cup at the time of fracture is a measure of ductility (see: cupping test; compare: Erichsen test), venitatavuskatse, mille käigus servades kinnitatud lehtmetallist proovitükki deformeeritakse standardsete mõõtmetega teraskuuliga kuni purunemiseni; purunemise hetkel moodustunud süvendi sügavus iseloomustab materjali venivust/plastsust (vt venitatavuskatse; vrd Erichseni katse)