Method of making joint for structure

A method for making a joint for a structure, comprising:

• forming a thermoplastic filler, having a length and made from a thermoplastic material;
• applying an uncured first thermoset layer into direct contact with the thermoplastic filler along the length of the thermoplastic filler, the uncured first thermoset layer comprising a first fibrous material embedded in a first thermoset matrix;
• applying an uncured second thermoset layer into direct contact with the thermoplastic filler along the length of the thermoplastic filler and into contact with the uncured first thermoset layer, the uncured second thermoset layer comprising a second fibrous material embedded in a second thermoset matrix;
• applying an uncured third thermoset layer into direct contact with the thermoplastic filler along the length of the thermoplastic filler and into contact with the uncured first and second thermoset layers, the uncured third thermoset layer comprising a third fibrous material, embedded in a third thermoset matrix;
• and
• while the uncured first, second, and third thermoset layers are applied into direct contact with the thermoplastic filler and while the uncured second thermoset layer contacts the uncured first thermoset layer and the uncured third thermoset layer, curing the uncured first thermoset layer, the uncured second thermoset layer, and the uncured third thermoset layer to form a cured first thermoset layer, a cured second thermoset layer, and a cured third thermoset layer and bond together the cured first thermoset layer, the cured second thermoset layer, the cured third thermoset layer, and the thermoplastic filler without melting the thermoplastic filler.

A method for forming a joint, the method comprising steps of:

• forming a thermoplastic filler, having a length and comprising a thermoplastic material and unidirectional reinforcement fibers;
• applying an uncured first thermoset layer into direct contact with the thermoplastic filler along the length of the thermoplastic filler, wherein the uncured first thermoset layer comprises a first fibrous material, embedded in a first thermoset matrix;
• applying an uncured second thermoset layer into direct contact with the thermoplastic filler along the length of the thermoplastic filler, wherein the uncured second thermoset layer comprises a second fibrous material, embedded in a second thermoset matrix;
• applying an uncured third thermoset layer into direct contact with the thermoplastic filler along the length of the thermoplastic filler, wherein:
• the uncured third thermoset layer comprises a third fibrous material, embedded in a third thermoset matrix,
• the uncured second thermoset layer is coupled to the uncured first thermoset layer and the uncured third thermoset layer to form the joint, and
• a gap is defined between the uncured first thermoset layer, the uncured second thermoset layer, and the uncured third thermoset layer;
• positioning the thermoplastic filler within the gap, wherein:
• the thermoplastic material of the thermoplastic filler has a melting temperature that is greater than a cure temperature of each of the first thermoset matrix and the second thermoset matrix,
• the melting temperature of the thermoplastic material of the thermoplastic filler is between about 450° F. and about 750° F., and
• the thermoplastic filler supports and maintains a first shape of a portion of the uncured first thermoset layer and a second shape of a portion of the uncured second thermoset layer;
• and
• while the uncured first thermoset layer, the uncured second thermoset layer, and the uncured third thermoset layer are applied into direct contact with the thermoplastic filler, curing the uncured first thermoset layer, the uncured second thermoset layer, and the uncured third thermoset layer without melting the thermoplastic material of the thermoplastic filler.