A fastener includes a head, a threaded member, and a resilient shank portion interconnecting the head portion and the threaded portion. The shank portion includes a first end adjacent the head and a second end adjacent the threaded member. The shank includes a tubular section having an inner wall and an outer wall between the first end and the second end. The tubular section has a curved axial profile. The tubular section is axially elastically deformed as the fastener is torqued down.