ADAPTIVE COMPOSITE HYDRAULIC CYLINDERS WITH EMBEDDED SHAPE MEMORY ALLOYS FIBERS

HYDRAULIC COMPONENTRY FOR AIRCRAFT BOMB RACK AND MISSILE LAUNCHER SYSTEMS REQUIRING VERY HIGH HYDRAULIC PRESSURES ARE BEING DEVELOPED, HOWEVER, TYPICALLY THE COMPONENT WEIGHT IS HIGH AND THERE IS A STRONG DESIRE TO INVESTIGATE METHODS TO REDUCE THE TOTAL WEIGHT. COMPONENTS MADE OF COMPOSITES AND HYBRIDS ARE DESIRABLE OPTIONS IN ORDER TO REDUCE WEIGHT AND THEREFORE MAXIMIZE AIRCRAFT FUEL EFFICIENCY AND SPEED. THIS PROPOSED EFFORT UTILIZES A NEW AND INNOVATIVE APPROACH TO LIGHTWEIGHT PRESSURE DEVICES, BASED ON SHAPE MEMORY ALLOY HYBRID COMPOSITES. SHAPE INENORY ALLOY (SMA) HYBRID COMPOSITES ARE A CLASS OF COMPOSITES WHICH CONTAIN EMBEDDED SMA FIBERS WHICH CAN ACT AS INTERNAL ACTUATORS TO RESIST THE TENSILE STRESSES CAUSED BY INTERNAL PRESSURE. IF SMA IS USED ON THE EXTERIOR OF A THIN-WALLED PRESSURE DEVICE, AND ELECTRIC CURRENT IS PASSED THROUGH THE SMA ACTUATORS, THE SMA WILL CREATE A COMPRESSIVE FORCE WITHIN THE MATERIAL. THIS RETURN FORCE IS ADEQUATE TO COUNTERACT THE HOOP STRESS OF THE THIN-WALLED PRESSURE DEVICE. THE RESULTING HYBRID COMPOSITE THIN-WALLED VESSEL WITH SMA ACTUATORS IS SIGNIFICANTLY LIGHTER THAN ALL-COMPOSITE VESSELS OR MONOLITHIC METALLIC VESSELS.