Abstract: A method for the production of a stiffener on a surface of an element that is to be made rigid, whereby at least one of the two is made of a composite material that is not completely polymerized, whereby the stiffener includes—in a transverse direction—two contact zones with the surface between which the stiffener and the element to be made rigid form a cavity that empties out at least one of the ends of the stiffener, includes using a core that is placed in the cavity and removed from the cavity after polymerization. The core has a first part that has a low expansion coefficient to ensure the geometric precision required and at least one second part that has a significant elongation coefficient to make possible the extraction of the part by traction on one of the ends of the second part so as to cause a contraction of its cross-section.

Abstract: A method for the production of a stiffener on a surface of an element that is to be made rigid, whereby at least one of the two is made of a composite material that is not completely polymerized, whereby the stiffener includes—in a transverse direction—two contact zones with the surface between which the stiffener and the element to be made rigid form a cavity that empties out at least one of the ends of the stiffener, includes using a core that is placed in the cavity and removed from the cavity after polymerization. The core has a first part that has a low expansion coefficient to ensure the geometric precision required and at least one second part that has a significant elongation coefficient to make possible the extraction of the part by traction on one of the ends of the second part so as to cause a contraction of its cross-section.