Pressure tunable expandable mandrel for manufacturing a composite structure
AssigneeBell Helicopter Textron Inc.
InventorsPaul K. Oldroyd, James D. Hethcock, Jr., David B. McNeill
Life of this patent
Estimating the term…
Abstract
A method of making a composite core can include configuring a plurality of mandrels to have a desired thermal expansion characteristic, placing a composite material around each mandrel, placing the plurality of mandrels in a tool, the tool being configured to constrain the plurality of mandrels as the mandrels experience a thermal expansion, heating the mandrels so that the mandrels thermally expand, thereby applying a pressure to the composite material during a cure cycle, and then cooling and separating the mandrels from the composite core. The mandrel is configured as an internal form for making a tube member of a composite core.
Claims7
A method of making a composite core, the method comprising:
- providing a plurality of mandrels, each mandrel comprising:
- a body portion with an outer surface, the outer surface defining an ultimate shape of a tube member of the composite core;
- and
- a hollow portion that defines an internal surface of the body portion, the hollow portion having a star shaped geometry that is collapsible in multiple pressure stages, the star shaped geometry having a plurality of flat walled leg portions that each terminate at a point, the plurality of flat walled leg portions extending from an interior portion;
- placing a composite material around each mandrel;
- placing the plurality of mandrels in a tool, the tool being configured to constrain the plurality of mandrels as the mandrels experience a thermal expansion;
- heating the mandrels so that the mandrels thermally expand, thereby applying a pressure to the composite material during a cure cycle, the step of heating the mandrels including increasing a temperature of the mandrels for a duration, the increase in temperature during the duration causing a first pressure plateau as the flat walled leg portions of the hollow portion collapse and second pressure plateau as a diameter of the interior portion collapses;
- and
- cooling and separating the mandrels from the composite core.
Dependencies are inferred from the claim text.