Co-authors​ :

 Aikaterini ANAGNOSTOPOULOU (GREECE), Konstantinos TSERPES (GREECE), Dimitris SOTIROPOULOS (GREECE), George GEORGIOS LAMPEAS (GREECE), Jorge Rafael GONZÁLEZ-TEODORO , Blanca CARRASCO LORAS (SPAIN) 

Efforts aim to achieve net-zero carbon emissions from international aviation by 2050, leading to extensive research on improving existing aircraft designs and developing more sustainable alternatives. Although 95% of aircraft emissions come from the use phase, closely tied to propulsion systems and fuel, a comprehensive assessment beyond these factors is critically needed. Material choices and manufacturing methods established during the design phase significantly impact environmental aspects throughout the aircraft component production, manufacturing, and end-of-life stages. Therefore, conducting a sustainability assessment before the final manufacturing of components is crucial to provide designers with essential guidance toward making more sustainable decisions in the early stages of design. This study focuses on conducting a cradle-to-gate sustainability assessment of two composite liquid hydrogen tank design options. Each tank comprises inner and outer insulated sections. The inner tank is made of thermoplastic CFRP material via the Large Format Additive Manufacturing process (LFAM). The outer tank consists of a cylindrical part made from thermoset CFRP material via the Automated Fiber Placement (AFP) process and two hemispherical caps made via the Hand Lay-Up process. The only difference between the two tank designs lies in the geometry of the outer tank.
For a tank design, we conducted a sustainability assessment using multi-criteria decision-making methods (MCDM). Firstly, we used SimaPro software to perform Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) analyses, gathering environmental and cost data. Upon analyzing the results, we conducted a sustainability assessment, considering environmental, cost, and performance criteria. We employed a robust method based on the traditional TOPSIS (Technique for Order Performance by Similarity to Ideal Solution) approach, which overcomes the rank reversal problem. After selecting the most sustainable design, we conducted a secondary hierarchical ranking to identify the less sustainable aspects of the tank. Finally, we carried out a univariate sensitivity analysis, systematically varying one parameter at a time while keeping the others constant. This analysis ensures that our conclusions are robust and justifiable across different criteria weighting scenarios using the Best-Worst Method (BWM).
Acknowledgement
The work described in the paper has been conducted in the frame of the EU funded Clean Aviation Project H2ELIOS (Grant Agreement: 101102003).