Composite drive shafts

A mechanical system for an aerospace application comprising:

• a drive input connected to a first axial end of a first diaphragm member, and a drive output connected to a second axial end of a second diaphragm member, and said drive output is an aerospace component;
• said first and second diaphragm members being formed with two axial ends and at least one undulation extending radially of said axial ends, and said at least one undulation being intermediate said ends, and a tubular portion connecting said first and second diaphragm members, said first and second diaphragm members and said tubular member being formed of fiber reinforced polymer matrix composites, and said first and second diaphragm members being connected to axial ends of said tubular member;
• joints formed by welding of said axial ends of said tubular portion to one of said inner ends of each of said first and second diaphragm members;
• wherein said joints receive reinforcement;
• wherein a separate fiber-reinforced polymer matrix composite sleeve provides said reinforcement;
• wherein said sleeve provides a radially extending step such that said sleeve has reinforcement portions at distinct radial positions;
• and
• wherein said sleeve is radially inward of said joints.