Active pressure relief valves and methods of use for regulating
atmospheric conditions within an interior compartment of a vehicle
generally include an active material to effect movement of a flap
relative to an opening. The active material has the ability to remember
its original at least one attribute such as dimension, shape, and/or
flexural modulus, which can subsequently be recalled by applying or
removing an external stimulus, as will be discussed in detail herein.
Suitable active materials include, without limitation, shape memory
alloys, ferromagnetic shape memory alloys, shape memory polymers,
piezoelectric materials, electroactive polymers, magnetorheological
fluids and elastomers, electrorheological fluids, composites of one or
more of the foregoing materials with non-active materials, combinations
comprising at least one of the foregoing materials, and the like.
Depending on the particular active material, the activation signal can
take the form of, without limitation, an electric current, a temperature
change, a magnetic field, a mechanical loading or stressing, or the like.