A composite driveshaft includes a body having a first end, a second end, and an intermediate portion defining a driveshaft axis (DSA). The first end defines a first coupling region and the second end defines a second coupling region. At least one of the first and second coupling regions defines a virtual hinge configured to accommodate both bending moments and axial changes of the body.

A flexible coupling includes an input body, an output body offset from the input body, and a flexible lattice body. The flexible lattice body includes a flex beam member coupling the input body to the output body. The flex beam member has a rounded cross-sectional area with a centrally disposed minimum cross-sectional area to reduce peak stress in the flex beam member while transferring torque and accommodating misalignment between the input body and the output body. The flexible coupling is jointless, simplifying fabrication, and has a free-form geometry, reducing weight.

A displacement compensating coupling comprises a first coupling member, a second coupling member and connecting elements for connecting the coupling members. The coupling members are each made in one piece from composite material and have a first flange portion for attachment to one of the drive elements, a diaphragm portion that extends radially outwardly from the first flange portion, a second flange portion and a tube portion extending from an outer circumference of the diaphragm portion to the second flange portion. Each of the tube portions has two or more recesses that are spaced from each other in circumferential direction. In a first relative position of the coupling members, the recesses of the first coupling member face the recesses of the second coupling member, and in a second relative position the recesses of the first coupling member and of the second coupling member are offset in circumferential direction.

A planar flexure member for resisting rotation about a central axis thereof includes, in various embodiments, a central portion comprising a plurality of attachment points; and at least one serpentine flexure arm extending from the central portion in a plane. The arm(s) terminate in an arcuate mounting rail that includes a series of attachment points. The rails are positioned in opposition to each other to partially define and occupy a planar circular envelope radially displaced from but surrounding the central portion of the flexure member. A portion of the serpentine arms may extend to (or substantially to) the envelope between the mounting rails.

A composite driveshaft includes a body having a first end, a second end, and an intermediate portion defining a driveshaft axis (DSA). The first end defines a first coupling region and the second end defines a second coupling region. At least one of the first and second coupling regions defines a virtual hinge configured to accommodate both bending moments and axial changes of the body.

A composite driveshaft includes a body having a first end, a second end, and an intermediate portion defining a driveshaft axis. The first end defines a first coupling region and the second end defines a second coupling region. At least one virtual hinge is arranged adjacent at least one of the first coupling region and the second coupling region. The at least one virtual hinge being defined by a plurality of axially extending openings forming a plurality of axially extending flexible material webs that accommodate both bending moments and axial changes of the body.

A planar flexure member for resisting rotation about a central axis thereof includes, in various embodiments, a central portion comprising a plurality of attachment points; and at least one serpentine flexure arm extending from the central portion in a plane. The arm(s) terminate in an arcuate mounting rail that includes a series of attachment points. The rails are positioned in opposition to to each other to partially define and occupy a planar circular envelope radially displaced from but surrounding the central portion of the flexure member. A portion of the serpentine arms may extend to (or substantially to) the envelope between the mounting rails.

A planar flexure member for resisting rotation about a central axis thereof includes, in various embodiments, a central portion comprising a plurality of attachment points; and at least one serpentine flexure arm extending from the central portion in a plane. The arm(s) terminate in an arcuate mounting rail that includes a series of attachment points. The rails are positioned in opposition to to each other to partially define and occupy a planar circular envelope radially displaced from but surrounding the central portion of the flexure member. A portion of the serpentine arms may extend to (or substantially to) the envelope between the mounting rails.

A flexible coupling assembly includes a power transmitting body to carry a torsional load between opposed rotating members and a quill shaft for carrying an axial load extending through the cavity of the torsional body. The power transmitting body defines an axis, a longitudinally extending cavity, and a first and second flanged portions for coupling opposed rotating members. The quill shaft extends through the cavity of the power transmitting body, spanning the power transmitting body, and fixed to the first and second flanged portions for carrying the axial load across the power transmitting body.