The University of Sheffield
Department of Civil and Structural Engineering

Parametric Modelling And Structural Optimisation For Additive Manufacturing

Supervisor: Dr Andrew Liew

Parametric modelling involves the use of a design workflow that allows for changes in key geometric parameters to be observed rapidly in the computer aided design workspace. It gives immense design freedom in creating solid geometries that would not ordinarily be feasible to model by hand. Structural optimisation is related to a set of processes and algorithms that shape the structure to some target objective, such as maximising stiffness/minimising volume or improving on some engineering, physical or architectural performance based criteria. The types of optimised geometries that are created are often vastly different from what is regularly designed for in engineering practise.

The digital outputs from both parametric modelling and structural optimisation are usually sufficiently complex that traditional manufacturing processes, even CNC cutting and milling routines, are unable to fabricate them effectively. Additive manufacturing, where solid material is built-up sequentially layer by layer, offers a gateway into realising these new, efficient and highly intricate structural forms. This research examines the relationships that form between the triangle of parametric modelling, structural optimisation and additive manufacturing, with the goal of directing the research findings to the generation of high performance structural elements for the construction industry. These elements can have many hundreds or thousands of members, thus processes must be designed that are semi-automated or automated in nature.

Areas of investigation include (but are not limited to): 1) how to translate digital high resolution optimised structural forms into something physical, 2) the effect of parametric patterning/topology methods on structural form and how it influences the design space, 3) the role of infill materials in 3D printing, 4) hybrid structural optimisation and parametric modelling techniques, and 5) interfacing with 3D printed materials and the additive manufacturing process. Structural optimisation methods applied to a variety of objective functions, will include discrete truss layout optimisation, constrained force density method form-finding and continuous topology optimisation, as well as structural verifications performed by finite element analyses. Modelling features heavily on this project, to generate highly detailed 3D geometries that marriage with the 3D printing technology and its limitations. CAD modelling will performed be via Rhinoceros, Grasshopper and Blender.

This position is for a PhD student working full-time, after the successful award of a departmental EPSRC Doctoral Training Partnerships (DTP), or through a self-funded / scholarship placement. To apply please send a two-page CV and covering letter to a.liew@sheffield.ac.uk.

This project is NOT FUNDED, although Departmental/University scholarships are available for applicants who can demonstrate strong evidence of research potential.

Pre-requisite qualification

The successful applicant is likely to have a first degree in engineering or architecture. He/she will also have sound computer programming skills, to enable them to take full advantage of state-of-the-art mathematical optimisation and form-finding methods. Hands-on experience of digital fabrication processes, particularly additive manufacturing/3D printing is desirable but not compulsory. Strong parametric design modelling skills, particularly in Rhinoceros and Grasshopper are needed from the start.