Title: A defect-aware experimental-numerical framework for flexural design of graded TPMS lattices manufactured by FDM

Authors: Mariangela Quarto; Flavio Caretto; Gianluca D'Urso

Addresses: Department of Management, Information, and Production Engineering, University of Bergamo, Via Pasubio 7/b, 24044 Dalmine (BG), Italy ' Ente Per Le Nuove Tecnologie, l'Energia e l'Ambiente, Via Appia km 706, 72100 Brindisi BR, Italy ' Department of Management, Information, and Production Engineering, University of Bergamo, Via Pasubio 7/b, 24044 Dalmine (BG), Italy

Abstract: This work investigates a key gap in current research by focusing on the flexural response of triply periodic minimal surface (TPMS) structures fabricated by fused deposition modelling technology. To provide a comprehensive understanding, experimental, tomographic, and numerical analyses were carried out. The study explores how cell size and graded relative density influence flexural performance. Three-point bending tests (based on ISO 178:2019) were combined with high-resolution micro-computed tomography (micro-CT) to quantify manufacturing-induced porosity, and with finite element (FE) simulations to validate the observed deformation mechanisms. Micro-CT analysis together with flexural characterisation and statistical analysis allow the definition of design guidelines connecting manufacturable wall thickness, relative-density gradients, and flexural efficiency. Finally, an industrial case study demonstrates the practical impact of this approach, applying TPMS infill to a pressurised tank to achieve substantial weight reduction while preserving mechanical integrity. These results highlight the potential of graded TPMS structures for lightweight, damage-tolerant components, and support their advancement toward Technology Readiness Level (TRL) 5-6.

Keywords: TPMS; triply periodic minimal surface; additive manufacturing; mechanical properties; finite element analysis.

DOI: 10.1504/IJMMS.2025.155741

International Journal of Mechatronics and Manufacturing Systems, 2025 Vol.18 No.4, pp.356 - 380

Received: 31 Mar 2026
Accepted: 15 May 2026
Published online: 12 Aug 2026 *

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