Fabrication of lightweight structural panels through ultrasonic consolidation

Abstract

A fundamental investigation of the feasibility of producing lightweight structural panels using ultrasonic consolidation (UC) was undertaken. As a novel solid freeform fabrication technology, UC utilizes both additive ultrasonic joining and subtractive CNC milling to enable the creation of complex aluminum structures with internal geometry at or near room temperature. A series of experiments were performed to understand the issues associated with sandwich structure fabrication using UC, including peel test experiments which evaluated the bond strength for various geometric configurations. The honeycomb lattice was found to offer the best core configuration due to its ability to resist vibration from the sonotrode and provide adequate support for pressure induced by the sonotrode. UC was found to be capable of producing lightweight and stiff structures, including honeycomb and other sandwich panels, without the use of adhesives. An effective manufacturing process plan for fabricating structural panels was developed. A case study was performed on a deck built for the TOROID small satellite spacecraft. The fabricated deck was tested for mechanical integrity. Finally, the cost and benefits of utilizing UC for lightweight structural panels versus traditional fabrication methods are discussed.