Creep assessment of thermoplastic materials for non-structural components in marine engines

The substitution of metals with fiber-reinforced polymers represents a well-established practice in the automotive and aerospace industries, driven by advantages such as cost reduction, weight savings, and environmental benefits. In the marine engineering sector, there is a growing interest in this metal replacement trend, particularly for non-structural components of marine engines that can be produced by adopting proper fiber-reinforced thermoplastic polymers. However, evaluating the suitability of such materials for marine applications necessitates a thorough understanding of their creep behavior, given the demanding operational environments and strict safety standards. The material selection process must intricately consider the material’s susceptibility to creep through tailored material design methodologies. Moreover, redesign activities should aim to leverage the material’s creep-resistant properties while ensuring adequate strength and simplifying installation procedures. Unfortunately, unlike the automotive industry, testing innovative plastic components in real environments on working engines is quite impossible. Neither engine manufacturers nor owners would allow jeopardizing their machinery by installing technologies not yet certified in a delicate environment such as a ship’s engine room. In this context, finite element simulations offer a valuable tool to assess the material’s creep performance and validate the proposed design when experimental measurements cannot be performed, hence predicting the component behavior over its intended lifetime. This study aims to exploit finite element analysis to evaluate the creep behavior and suitability for marine engine applications of a fiber-reinforced thermoplastic material, focusing on a camshaft cover of a four-stroke marine engine currently manufactured from aluminum alloy. Through numerical simulations, a commercial 30 % wt GFs/PA6,6 thermoplastic composite emerges as a promising candidate, demonstrating adequate creep resistance while significantly reducing weight, processing costs, and energy consumption. The results obtained from the present study lay the foundations for the adoption of such material-based technology also in the marine engine sector despite the difficulties coming from the peculiarities of this industry.