Flexible mandrel for forming composite structures

A method for forming a composite structure, the method comprising:

• laying up composite material over a tool, wherein the tool comprises a first mandrel having a first plurality of cured composite planks running parallel to each other and a first number of layers of flexible material positioned between and bonded to the first plurality of cured composite planks, and a second mandrel positioned adjacent to the first mandrel, wherein the second mandrel has a second plurality of cured composite planks running parallel to each other and a second number of layers of flexible material positioned between and bonded to the second plurality of cured composite planks;
• covering the composite material and the tool with a vacuum bag;
• applying pressure to the composite material and the tool using the vacuum bag;
• and
• curing the composite material to form the composite structure, wherein the tool deforms along its length to prevent inconsistencies from forming in the composite structure during curing.

A composite manufacturing system for forming an aircraft structure, the composite manufacturing system comprising:

• a first mandrel having a first plurality of cured composite planks running parallel to each other and a first number of layers of flexible material positioned between and bonded to the first plurality of cured composite planks;
• a second mandrel positioned adjacent to the first mandrel, wherein the second mandrel has a second plurality of cured composite planks running parallel to each other and a second number of layers of flexible material positioned between and bonded to the second plurality of cured composite planks;
• and
• a vacuum bag surrounding the first mandrel and the second mandrel, the vacuum bag configured to apply pressure to a composite material positioned over the first mandrel and the second mandrel to form the aircraft structure.