Abstract: An elastomeric compression spring for isolating vibrations between a first part and a second part. The first part is movable in a direction relative to the second part. The elastomeric compression spring comprises a tube elongated along a central axis of the tube. The central axis of the tube is perpendicular to the direction. The tube is configured to compress in the direction. The tube comprises an outer surface comprising an initial contact line configured to initially receive contact from the first part. The tube further comprises at least one load tuning feature in the outer surface, parallel to the central axis, and circumferentially spaced apart from the initial contact line. The at least one load tuning feature creates a localized change in a thickness of the tube and a stiffness of the elastomeric compression spring at the at least one load tuning feature.

Abstract: A fuel system for a rotorcraft is provided. The fuel system comprises a housing, a fuel bladder located within the housing, a first fuel reservoir, and a number of pressure relief valves. The first fuel reservoir is in fluid communication with the fuel bladder and stowed within the housing. The number of pressure relief valves are configured to divert fuel from the fuel bladder into the first fuel reservoir at a predetermined pressure such that the first fuel reservoir expands to reduce forces on the housing during a crash event.

Abstract: An elastomeric compression spring for isolating vibrations between a first part and a second part. The first part is movable in a direction relative to the second part. The elastomeric compression spring comprises a tube elongated along a central axis of the tube. The central axis of the tube is perpendicular to the direction. The tube is configured to compress in the direction. The tube comprises an outer surface comprising an initial contact line configured to initially receive contact from the first part. The tube further comprises at least one load tuning feature in the outer surface, parallel to the central axis, and circumferentially spaced apart from the initial contact line. The at least one load tuning feature creates a localized change in a thickness of the tube and a stiffness of the elastomeric compression spring at the at least one load tuning feature.

Abstract: Structurally tunable cores are described that can be implemented, for example, in aircraft components. An example flex beam for coupling a rotor blade to a rotor hub includes a first composite laminate, a second composite laminate, a third composite laminate, first resilient core members and second resilient core members. The first composite laminate forms a first skin of the flex beam. The second composite laminate is located opposite the first composite laminate and forms a second skin of the flex beam. The third composite laminate is located between the first composite laminate and the second composite laminate. The first resilient core members extend between the first composite laminate and the third composite laminate. The second resilient core members extend between the second composite laminate and the third composite laminate.

Abstract: An elastomeric compression spring for isolating vibrations between a first part and a second part. The first part is movable in a direction relative to the second part. The elastomeric compression spring comprises a tube elongated along a central axis of the tube. The central axis of the tube is perpendicular to the direction. The tube is configured to compress in the direction. The tube comprises an outer surface comprising an initial contact line configured to initially receive contact from the first part. The tube further comprises at least one load tuning feature in the outer surface, parallel to the central axis, and circumferentially spaced apart from the initial contact line. The at least one load tuning feature creates a localized change in a thickness of the tube and a stiffness of the elastomeric compression spring at the at least one load tuning feature.

Abstract: Structurally tunable cores are described that can be implemented, for example, in aircraft components. An example flex beam for coupling a rotor blade to a rotor hub includes a first composite laminate, a second composite laminate, a third composite laminate, first resilient core members and second resilient core members. The first composite laminate forms a first skin of the flex beam. The second composite laminate is located opposite the first composite laminate and forms a second skin of the flex beam. The third composite laminate is located between the first composite laminate and the second composite laminate. The first resilient core members extend between the first composite laminate and the third composite laminate. The second resilient core members extend between the second composite laminate and the third composite laminate.

Abstract: A fuel system for a rotorcraft is provided. The fuel system comprises a housing, a fuel bladder located within the housing, a first fuel reservoir, and a number of pressure relief valves. The first fuel reservoir is in fluid communication with the fuel bladder and stowed within the housing. The number of pressure relief valves are configured to divert fuel from the fuel bladder into the first fuel reservoir at a predetermined pressure such that the first fuel reservoir expands to reduce forces on the housing during a crash event.

Abstract: A composite structural member and an arrangement of such composite structural members are constructed to provide a multi-functional under-floor airframe that reacts flight, handling and internal cargo loads, and is capable of absorbing energy when subjected to vertically applied compression loads, such as loads that may be applied in hard landing or crash situations. The composite structural member and arrangement of such composite structural members adds no parasitic weight to the aircraft, i.e., there is no need for additional energy-absorbing systems, structures or mechanism; and is lighter weight as compared to metal. The composite structural member and related parts of the arrangement of such composite structural members are designed to progressively collapse throughout the stroke (or displacement) that occurs when a dynamic compressive load is applied to the structural member and to work together with crashworthy seats to mitigate injuries to occupants.

Abstract: A vibration damper including a frame having at least a first cavity, a frame first end and a frame second end spaced from the frame first end; a shaft slidably coupled to and extending into the frame where the shaft extends through the first cavity; a first vibration isolator disposed within the first cavity where the shaft extends through the first vibration isolator so as to capture the first vibration isolator within the first cavity where the first vibration isolator interfaces with the frame second end; and a second vibration isolator disposed on the shaft, where the shaft extends through the second vibration isolator so as to capture the second vibration isolator on the shaft where the second vibration isolator interfaces with the frame second end opposite the first vibration isolator, where the first vibration isolator and the second vibration isolator act only in compression.

Abstract: An elastomeric compression spring for isolating vibrations between a first part and a second part. The first part is movable in a direction relative to the second part. The elastomeric compression spring comprises a tube elongated along a central axis of the tube. The central axis of the tube is perpendicular to the direction. The tube is configured to compress in the direction. The tube comprises an outer surface comprising an initial contact line configured to initially receive contact from the first part. The tube further comprises at least one load tuning feature in the outer surface, parallel to the central axis, and circumferentially spaced apart from the initial contact line. The at least one load tuning feature creates a localized change in a thickness of the tube and a stiffness of the elastomeric compression spring at the at least one load tuning feature.

Abstract: A protective assembly includes a gas bag and a fuel container which includes a first wall. The fuel container is positioned within an aircraft and the gas bag extends along the first wall of the fuel container. A method for assembling a protective assembly includes the step of positioning a gas bag within an aircraft such that the gas bag extends along a first wall of a fuel container.

Abstract: A composite structural member and an arrangement of such composite structural members are constructed to provide a multi-functional under-floor airframe that reacts flight, handling and internal cargo loads, and is capable of absorbing energy when subjected to vertically applied compression loads, such as loads that may be applied in hard landing or crash situations. The composite structural member and arrangement of such composite structural members adds no parasitic weight to the aircraft, i.e., there is no need for additional energy-absorbing systems, structures or mechanism; and is lighter weight as compared to metal. The composite structural member and related parts of the arrangement of such composite structural members are designed to progressively collapse throughout the stroke (or displacement) that occurs when a dynamic compressive load is applied to the structural member and to work together with crashworthy seats to mitigate injuries to occupants.

Abstract: A tool for laying up composite material to form a workpiece having a target contour is disclosed. The tool includes a support structure including an elongated member having a longitudinal axis, and support plates connected to the elongated member and spaced apart from each other along the longitudinal axis. The elongated member includes a metallic material. The tool also includes a non-metallic backing structure connected to the support plates, the non-metallic backing structure comprising a working surface that includes a backing contour complementary to the target contour.

Abstract: A vibration damper including a frame having at least a first cavity, a frame first end and a frame second end spaced from the frame first end; a shaft slidably coupled to and extending into the frame where the shaft extends through the first cavity; a first vibration isolator disposed within the first cavity where the shaft extends through the first vibration isolator so as to capture the first vibration isolator within the first cavity where the first vibration isolator interfaces with the frame second end; and a second vibration isolator disposed on the shaft, where the shaft extends through the second vibration isolator so as to capture the second vibration isolator on the shaft where the second vibration isolator interfaces with the frame second end opposite the first vibration isolator, where the first vibration isolator and the second vibration isolator act only in compression.

Abstract: A protective assembly includes a gas bag and a fuel container which includes a first wall. The fuel container is positioned within an aircraft and the gas bag extends along the first wall of the fuel container. A method for assembling a protective assembly includes the step of positioning a gas bag within an aircraft such that the gas bag extends along a first wall of a fuel container.

Abstract: One example of the present disclosure relates to a tool for laying up composite material to form a workpiece having a target contour. The tool includes a support structure including an elongated member having a longitudinal axis, and support plates connected to the elongated member and spaced apart from each other along the longitudinal axis. The elongated member includes a metallic material. The tool also includes a non-metallic backing structure connected to the support plates, the non-metallic backing structure comprising a working surface that includes a backing contour complementary to the target contour.

Abstract: One example of the present disclosure relates to a tool for laying up composite material to form a workpiece having a target contour. The tool includes a support structure including an elongated member having a longitudinal axis, and support plates connected to the elongated member and spaced apart from each other along the longitudinal axis. The elongated member includes a metallic material. The tool also includes a non-metallic backing structure connected to the support plates, the non-metallic backing structure comprising a working surface that includes a backing contour complementary to the target contour.

Abstract: An energy absorbing fitting is constructed to absorb tension, shear and compression loads at a joint between two composite material beams of a composite material frame. The fitting is constructed with a band of composite material having an inverted U-shape, a panel of composite material having a U-shaped cross-section configuration that is assembled into the inverted U-shaped configuration of the band, and a sheet of composite material having an inverted L-shape configuration that is secured to the band and to the panel. The fitting is positioned at the intersection of the beams and is secured to the joint between the beams, thereby reinforcing the joint against tension, shear and compression loads.

Abstract: An apparatus and method for a composite structural aircraft transmission support link having an integral energy-absorbing feature is disclosed. The link is a two-force member that can carry structural loads up an ultimate load. When loaded beyond ultimate load the design allows sections of the link to fail in a controlled and progressive manner, so that energy is absorbed over a defined stroking distance.

Abstract: An energy absorbing fitting is constructed to absorb tension, shear and compression loads at a joint between two composite material beams of a composite material frame. The fitting is constructed with a band of composite material having an inverted U-shape, a panel of composite material having a U-shaped cross-section configuration that is assembled into the inverted U-shaped configuration of the band, and a sheet of composite material having an inverted L-shape configuration that is secured to the band and to the panel. The fitting is positioned at the intersection of the beams and is secured to the joint between the beams, thereby reinforcing the joint against tension, shear and compression loads.