Lightweight Design of a Connecting Rod Using Lattice-Structure Parameter Optimisation: A Test Case for L-PBF

Lightweight design is a common way of reducing mass while enhancing the performance of mechanical components. The paper proposes a method to analyse the substitution of bulk volume with optimised lattice structures. The approach considers an early DoE analysis to explore the design space, Finite Element Analysis to evaluate the feasibility of possible design solutions, and Artificial Intelligence tools to look for optimal design solutions, including Genetic Algorithms and Response Surface Methods. To validate the methodological approach, this work proposes the design optimisation of a lightweight diesel engine connecting rod, redesigned using Triply Periodic Minimal Surface (TPMS) lattice structures where they are functionally convenient. The TPMS cells analysed are gyroid, diamond, and SplitP. Laser-Powder Bed Fusion (L-PBF) is the Additive Manufacturing process considered during the redesign phase. The resulting connecting rod achieves a mass of roughly 614 g, obtaining a lightweight of more than 50% of the initial weight, using gyroid lattice structures and titanium alloy powders such as Ti6Al4V.