Resistance Welding of Carbon Fiber Reinforced Thermoplastic Composites for Repurposable Applications

The investigation team is proposing to develop resistance welding of carbon fiber reinforced thermoplastic composites (TPCs) specifically for repurposable aerospace applications. The proposed innovation addressed the requirements of 2023 Phase 1 Topic T12.09 seeking to exploit unique properties of thermoplastic composites to assess their feasibility and propose concepts of operations for in situ repurposing of primary and secondary spacecraft structures into deep space exploration infrastructure supporting sustainable human presence beyond low Earth orbit (LEO). For example, the landing strut of a descent stage exploration vehicle can be repurposed as an antenna, habitat structure, or solar panel towers, allowing NASA to address the challenges of expensive up-mass. A qualified and intelligent handheld joining unit and kit for astronauts will be significant for NASA as it will accelerate the feasibility of repurposing materials in space, contributing to a more sustainable space exploration effort. During Phase I the team successfully demonstrated the developed bench top compact weld unit and performed TPC welds with innovative heating elements to obtain high lap shear strength. Building on the success of the Phase 1 effort, the team is proposing to deliver at the end of Phase II an intelligent weld unit with feedback loop requiring minimal crew participation. This will be achieved by (1) expanding the material portfolio to other reinforced thermoplastics and optimizing specific weld parameters, (2) quantifying mechanical properties as a function of cooling rate and lunar and martian thermal extreme boundary conditions, (3) optimizing Z pin and other innovative mesh heating element configuration and surface treatment to maximize mechanical properties, and (4) designing and building an intelligent hand held weld unit and associated weld kit for several thermoplastics that can be subjected to NASA flight qualification procedures.