Experimental and numerical study of Triply Periodic Minimal Surface structures

Fu, Hao ORCID: 0000-0003-1262-8113 (2024). Experimental and numerical study of Triply Periodic Minimal Surface structures. University of Birmingham. Ph.D.

Preview

Fu2024PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (25MB) | Preview

Abstract

3D printing is an emerging additive manufacturing technology that has revolutionised the development of new materials and structures across various industries. Its ability to produce complex shapes with ease has notably contributed to many fields. Among these innovations, Triply Periodic Minimal Surface (TPMS) structures stand out as a novel type of porous structures, characterised by their particular features such as high specific strength and stiffness. These structures, resembling forms found in biological systems, have become a focal point in materials research over the last decade.
In the last few years, civil engineering practitioners started exploring applying TPMSs in their field. Previous studies on TPMS, however, have largely focused on small-scale material properties, limiting their direct applicability in civil engineering contexts. The structural properties of large-scale TPMS structures, including their static and dynamic characteristics, remain largely undefined. This gap signifies a crucial need for further exploration of large-scale TPMS structures, especially for applications in civil engineering, like railway engineering.
This thesis investigates the suitability of TPMS structures for civil engineering (specifically railways), undertaking a series of static and dynamic studies. The research begins by establishing simplified models of several TPMSs and proceeds to design corresponding solid models. Several TPMS structures have been 3D printed to create large-scale samples for compressive testing. Based on these tests, Finite Element Method (FEM) models of individual unit cells are developed and validated, allowing for the generation of complex structures and their subsequent numerical analysis.
To examine the effect of unit arrangement on the mechanical and cracking behaviours of specific TPMS structures, the Discrete Element Method (DEM) has been employed. This approach utilises the compressive test data of individual units to validate the DEM models. The study then numerically simulates various TPMS configurations, performing a mesoscopic analysis of their behaviour.
To assess the dynamic properties of these structures, multiple TPMS units have been 3D printed and subjected to impact hammer tests. This testing analyses the frequency, dynamic stiffness, and damping characteristics of the structures. A combined DEM and FEM approach conceptualises the TPMS structure as a support layer in railway applications, examining its mechanical performance under sleeper displacement. Finally, the thesis explores the applicability of concrete TPMS structures by modelling concrete TPMS structures under combined compressive and torsional loads via DEM.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):