Sustainability Integration in Engineering Practice

Abstract

Having seen exponential growth in demand for air travel, the aviation industry has found itself trying to find a balance between economic growth, technological development, and environmental sustainability. This saw a shift in attention towards materials such as fiber reinforced composites, predominantly thermoset in the past with higher strength-to-weight fractions. Relatively recent was the introduction of high-performance fiber reinforced thermoplastic polymer composite materials possessing more promising prospects of circularity in addition to the lightweighting capabilities. But as is, these only form for qualitative claims with no indication on how the ecological effects would pan out over the life cycle phases objectively, as well as on a relative scale.

Extending beyond the orthodox considerations and measures of aircraft performance, life cycle assessment studies encompass a comprehensive analysis of the environmental impact associated with aerospace products through the various phases of their life cycle including material extraction/production, manufacturing, operation, and the respective end-of-life treatment. The primary objective is to quantify the environmental impact of the system, offering a holistic view of the emissions, energy demand, and resource consumption.

To this end, this study constructed a comparative environmental profile, modelling for five material/manufacturing systems, namely numerically machined aluminium alloy, autoclave cured and resin transfer molded carbon fiber reinforced epoxy, autoclave consolidated, and press consolidated carbon fiber reinforced Polyetherketoneketone (PEKK) over the cradle-to-gate and the cradle-to-end of service phases in an attempt to find the best variant from an environmental perspective, while also adding a novel, semi-quantitative, robust framework of data quality assessment to the state-of-the-art.

The characterization results, under the assumption of each scenario yielding a product of the same mass and equal importance being given to each impact category (equal weighting), indicated the press consolidated carbon fiber reinforced PEKK product to be the scenario with the lowest impact over the cradle-to-gate (including only material production/extraction and product manufacturing). Over the cradle-to-end of service phases (including material production/extraction, product manufacturing, and the operational phase of the aircraft), the operational phase was observed to have an exponentially larger impact compared to the other life cycle phases causing the comparative profile to homogenize. This was reiterated by outcomes of the performed contribution analyses. Sensitivity analyses were conducted to explore the environmental benefits of lightweighting and processing waste optimization (buy-to-fly ratios quantifying the relative, quantitative benefits of lighter products and leaner manufacturing systems.