The thermally responsive actuator described in this disclosure includes a housing, a thermal expansion material, a piston, and a closure assembly. The housing has an internal cavity and an opening that leads into the cavity. The thermal expansion material is placed inside the cavity. The piston extends at least partially through the opening into the cavity. The closure assembly, which includes a cover and a sealing system, is attached to the housing at the opening. It covers the opening and surrounds the piston. The sealing system includes two sealing members: a first and a second. The housing and/or the cover has two separate compartmentsone for each sealing memberpositioned along the same axis but separated by the cover.

A system can be used to anchor a contracting member (e.g., a shape memory material member). The system can include a structure including a surface and defining an aperture, a housing, and a contracting member. An end portion of the contracting member can extend through the housing, on the surface of the structure in more than one loop about the aperture, and back through the housing. The housing can be deformed around the contracting member extending through the housing. The system can also include a fastener received in the aperture such that a portion of the contracting member is secured between the surface of the structure and the fastener.