초록 ▼

A method for facilitating removal of a mandrel in the manufacture of hollow composite structures. A mandrel of substantially constant diameter is selected having a composition and coefficient of thermal expansion sufficient to enable it to expand when subjected to an elevated temperature. The mandre

A method for facilitating removal of a mandrel in the manufacture of hollow composite structures. A mandrel of substantially constant diameter is selected having a composition and coefficient of thermal expansion sufficient to enable it to expand when subjected to an elevated temperature. The mandrel is preheated to at least a predetermined minimum elevated temperature to thereby expand the mandrel radially outwardly. Composite material is wound around the mandrel while the mandrel has a temperature of at least the predetermined minimum elevated temperature. The composite material is then cured using any suitable curing technique. When the composite material has been cured, the mandrel is cooled to contract the mandrel radially inwardly, and the mandrel is removed from the composite material. This method of manufacture and removal is so effective that mandrels of constant diameter have been removed by hand from composite tubes of thirty feet in length.

대표청구항 ▼

[ What is claimed is:] [1.] A method for facilitating removal of a mandrel in the manufacture of hollow composite structures, said method comprising the steps of:(a) selecting a mandrel having a composition and coefficient of thermal expansion sufficient to enable said mandrel to expand when subject

[ What is claimed is:] [1.] A method for facilitating removal of a mandrel in the manufacture of hollow composite structures, said method comprising the steps of:(a) selecting a mandrel having a composition and coefficient of thermal expansion sufficient to enable said mandrel to expand when subjected to an elevated temperature;(b) preheating the mandrel to at least a predetermined minimum elevated temperature thereby expanding said mandrel radially outwardly to provide an expanded mandrel;(c) winding composite material around the expanded mandrel while said expanded mandrel has a temperature of at least said predetermined minimum elevated temperature;(d) curing the composite material without stretching said composite material during said curing to provide a cured composite material;(e) cooling the expanded mandrel thereby contracting said expanded mandrel radially inwardly to provide a contracted mandrel; and(f) removing the contracted mandrel from the cured composite material.