Hollow seem yog ib yam khoom ntawm ib qho geometry ua los ntawm hlau los yog hlau thiab cov khoom uas muaj lub zog thiab toughness (xws li yas, aluminium, iav fiber, thiab lwm yam) los ntawm dov, extrusion, casting thiab lwm yam. Xws li lub kaum sab xis steel, channel steel, I-beam, square steel, H-beam, thiab lwm yam yog ib yam khoom ntawm ib tug tej yam geometry ua los ntawm hlau los yog hlau thiab cov khoom muaj ib tug tej yam lub zog thiab toughness (xws li yas, txhuas, iav fiber. , thiab lwm yam) los ntawm dov, extrusion, casting thiab lwm yam. Xws li lub kaum sab xis steel, channel steel, I-beam, square steel, H-beam, thiab lwm yam.