Honeycomb core stabilization for composite parts

A process for making a partially stabilized flexible honeycomb core comprising the steps of:

• (a) providing a flexible honeycomb sheet and an adhesive film;
• (b) forming a honeycomb core preform by positioning the adhesive film onto only one exterior surface of the flexible honeycomb sheet such that the adhesive film entirely covers only the one exterior surface while an opposite exterior surface of the flexible honeycomb sheet remains uncovered;
• and
• (c) forming the partially stabilized flexible honeycomb core from the honeycomb core preform by adhering the adhesive film to only the one exterior surface of the honeycomb sheet to thereby form a stabilizing layer on only the one exterior surface of the flexible honeycomb sheet, wherein
• step (c) comprises subjecting the honeycomb core preform to atmospheric pressure cure conditions at an elevated temperature while maintaining the opposite exterior surface uncovered to thereby form the partially stabilized flexible honeycomb core that is partially stabilized against compressive forces exerted in widthwise and lengthwise directions thereof yet allows flexible bending of the partially stabilized flexible honeycomb core about axes in widthwise and lengthwise directions thereof.

A process for making a cured curved rigid honeycomb core composite laminate structure comprising:

• (a) forming a honeycomb core preform comprised of a flexible honeycomb sheet and a stabilizing layer comprised of an adhesive film in contact with and covering entirely only one exterior surface of the flexible honeycomb sheet such that an opposite exterior surface of the flexible honeycomb sheet remains uncovered by the adhesive film;
• (b) subjecting the honeycomb core preform formed according to step (a) to ambient atmospheric pressure cure conditions at an elevated temperature sufficient to adhere the adhesive film entirely covering only the one exterior surface to the one exterior surface of the flexible honeycomb sheet and thereby provide a partially stabilized honeycomb core that is partially stabilized against compressive forces exerted in widthwise and lengthwise directions thereof yet allows flexible bending of the partially stabilized honeycomb core about axes in the widthwise and lengthwise directions thereof;
• (c) manipulating the partially stabilized honeycomb core about at least one of the widthwise and lengthwise directions thereof to form at least one curvature and thereby achieve a near net final curved product shape of the partially stabilized honeycomb core;
• (d) laying up a plurality of resin-impregnated fiber-reinforced plies which envelope all exterior surfaces of the partially stabilized honeycomb core while in the near net final curved product shape thereof to form a final curved product preform;
• and
• (e) subjecting the final curved product preform to high temperature and high pressure autoclave curing conditions sufficient to cure the plurality of resin-impregnated fiber-reinforced plies and provide the cured curved rigid honeycomb core composite laminate structure.