Author(s)

MILOŠ BOGATAJ, LIDIJA ČUČEK, TOMAŽ ŽULA, STOJAN KRAVANJA, ZDRAVKO KRAVANJA

Abstract

The solutions to engineering systems should not only be feasible but should also be beneficial to all the pillars of sustainable development (economic, environmental and social) to the greatest possible extent. However, due to the inherent trade-offs among the three components of sustainable development, identifying such solutions is not a straightforward task. In this manuscript, we present a simultaneous approach for sustainable synthesis and optimization of engineering systems based on a mixed-integer (non)linear programming MI(N)LP. The approach aims at providing sustainable solutions and an insight into the trade-offs among the economic, environmental and social component of sustainable development. Maximization of a sustainability profit, which is a composite criterion comprised of economic, eco- and social profits, is applied in order to obtain the optimal sustainable solutions. The solutions are compared to those obtained by maximizing either pure economic profit or minimizing Green House Gas emissions. The approach is tested on two case studies and the results are compared. The first example is a simple example from the field of civil engineering. The example presents the synthesis/optimization of a 5.5 meters long cantilever beams. The second example represents supply chain synthesis/optimisation of a biogas production plant in Slovenia. The results for the first case study indicate that 23% increase in sustainability profit causes slight decrease in economic profit (6%). On the other hand, the results for the second case study indicate that a slight increase in sustainability profit (6%) causes a 27% decrease in economic profit. Nevertheless, the solutions obtained by maximizing the sustainability profit remain economically viable due to its composite nature that properly captures and reflects the trade-offs.

Keywords

engineering systems, optimization, synthesis, mixed-integer programming, cantilever structure, supply chain, sustainability, sustainability profit