Methods and systems for forming integral composite parts with a SMP apparatus

A method of fabricating a composite part with integrated stiffeners, the method comprising:

• triggering a shape memory polymer (SMP) apparatus to a malleable state, wherein the SMP apparatus is located within an outer mold, wherein ends of the SMP apparatus are sealed to at least one of an inner mandrel tool and the outer mold;
• inducing a pressure differential sufficient to drive the SMP apparatus, in the malleable state, against the outer mold, thereby shaping the SMP apparatus with a desired configuration of a first surface of the composite part to be formed and to include one or more cavities configured for placement of the stiffeners therein;
• triggering the SMP apparatus to a rigid state;
• placing the stiffeners into the cavities;
• applying composite material onto the SMP apparatus and exposed surfaces of the stiffeners resting within the cavities;
• and
• co-curing or co-bonding the stiffeners with the composite material on the SMP apparatus via pressure and heat to fabricate the composite part, including the steps of:
• sealing an impermeable sheet of material around the composite material;
• compressing the impermeable sheet of material toward the composite material by inducing a pressure differential outward and/or inward of the impermeable sheet of material;
• and
• heating the composite material to a composite cure temperature, with the SMP apparatus in the rigid state while the impermeable sheet of material compresses the composite material.

A method of fabricating a composite part with integrated stiffening features, the method comprising:

• placing a shape memory polymer (SMP) apparatus over an inner mandrel tool;
• sealing ends of the SMP apparatus to the inner mandrel tool;
• placing the SMP apparatus and inner mandrel tool into an outer mold;
• triggering the SMP apparatus to a malleable state;
• inflating the SMP apparatus toward the outer mold, thereby shaping the SMP apparatus in the malleable state to generally correspond with a desired configuration of a first surface of the composite part to be formed and to include one or more cavities configured for placement of the internal stiffeners therein;
• triggering the SMP apparatus to a rigid state;
• separating the SMP apparatus, in its rigid state, and the outer mold from each other;
• placing the internal stiffeners into the cavities;
• applying composite material onto the SMP apparatus and exposed surfaces of the internal stiffeners resting within the cavities;
• co-curing or co-bonding the internal stiffeners with the composite material on the SMP apparatus via pressure and heat to fabricate the composite part, including the steps of:
• sealing an impermeable sheet of material around the composite material,
• compressing the impermeable sheet of material toward the composite material by inducing a pressure differential outward and/or inward of the impermeable sheet of material, and
• heating the composite material to a composite cure temperature, with the SMP apparatus in the rigid state while the impermeable sheet of material compresses the composite material;
• removing the impermeable sheet of material from the composite part;
• triggering the SMP apparatus from the rigid state to the malleable state;
• and
• removing the SMP apparatus from within the composite part while the SMP apparatus is in the malleable state.