Abstract: Variable sleeve clearance control systems for gas turbine engines are disclosed. An example variable sleeve clearance control system for a gas turbine engine includes a sleeve comprising a first end and a second end, the first end of the sleeve coupled to a first spring that biases the sleeve inward, and the second end of the sleeve coupled to a second spring that biases the sleeve outward, a proximity sensor to measure a clearance width, and a controller for each of the first and second springs, the controller to obtain the measured clearance width from the proximity sensor and determine a response of the first and second springs.

Abstract: Cantilevered airfoils and methods of forming the same are disclosed herein. An example airfoil disclosed herein includes an airfoil including an airfoil body including a first face and a second face, a first recessed portion formed in the first face and internal temperature-regulating features and a first insert disposed within the first recessed portion, the first insert causing the airfoil body to assume a first predefined curvature profile at a first temperature, the first insert causing the airfoil body to assume a second predefined curvature profile at a second temperature.

Abstract: A reconfigurable tool and/or die geometry and methods of use generally comprise forming at least a portion of a shape defining surface with a shape memory material. In response to an activation signal, the shape memory material changes geometry of the shape defining surface to provide a means for forming parts with different geometries from the same tool and/or die. In an alternative embodiment, an insert for a tool and/or die can be used, wherein the insert has at least a portion of its shape defining surface formed of a shape memory material. Also disclosed are processes for forming a first part with a defined geometry and a second part with a defined geometry different from the first part defined geometry using a reconfigurable tool and/or die as well as a reconfigurable insert with a standard tool and/or die.

Abstract: Tunable structural member for a vehicle generally comprises an active material adapted to selectively undergo a change in at least one attribute in response to an activation signal. The change in the at least one attribute results in a change in the mechanical properties of the tunable structural member. Active materials generally include shape memory alloys, shape memory polymers, magnetorheological fluids and elastomers, piezoelectrics, electroactive polymers, and the like.