Session: 01-12-01: Spacecraft Structures 1

Paper Number: 151798

151798 - Amorphous Bonding for In-Space Welding of Thermoplastic Composite Deployable Structures 

In this study, the goal is to optimize the weld quality of deployable space structures composed of thermoplastic composites for in-space reusability and structural reconfiguration. To meet the demand for high volume-to-weight ratio of space structures, stowing segments of a deployable structure and performing in-space welding offers an optimal solution. Thermoplastic welding relies on fusion bonding through intimate contact, healing, and solidification between plies to form laminates or bond parts. However, crystallization poses challenges during thermoplastic processing, as it impairs interface healing and requires slow cooling to achieve proper fiber-matrix adhesion, which limits cycle times. To address this, composite material is developed by applying an amorphous polyetherimide (PEI) sheath to the surface of a semi-crystalline polyether ether ketone (PEEK) composite. This sheath is miscible with and healable below the melt temperature of the semi-crystalline polymer, resulting in a thermoplastic prepreg that is cooling-rate independent. The novel material system is referred to as Out-of-autoclave Amorphous/Crystalline Thermoplastic Materials for Energy-efficient Aerospace-grade Laminates (OATMEAL).  This research initiates an exploration into the potential of OATMEAL for deployable structures, presenting a series of mechanical characterizations. The study includes evaluating the bending stiffness of a laminate in the fiber direction (D₁₁) using a four-point bending test. Failure in the large-curvature regime is assessed through the Column Bending Test (CBT) fixtures. Finally, a case study is proposed to analyze the effects of amorphous bonding and bonding density on Model I and Mode II interface fracture toughness.

Presenting Author: Miguel Mireles The University of Texas at El Paso

Presenting Author Biography: Name: Miguel Mireles

Institution: The University of Texas at El Paso

Email Address: mgmireles@miners.utep.edu