Joe Gattas

• The University of Queensland

Existing computational design tools for steel connection design predominantly employ a point-based design (PBD) approach, which requires iterative re-evaluation whenever there are changes in design specifications. This paper introduces a new framework that adopts a set-based design (SBD) approach, aiming to substantially reduce the iteration and ti...

Emergency temporary housing is a critical component of post-disaster response and recovery. Their successful deployment requires structures to be low cost, easy to assemble, and with a capacity to adapt to local material and manufacturing availability. This paper proposes a novel ‘strap joint’ for the rapid assembly of lightweight timber elements a...

This paper aims to characterise the mechanical behaviour of folded timber sandwich structures developed using integral rotational press-fit (RPF) joints. Six folded arches are tested to failure, under three load cases designed to induce different sagging and hogging conditions at internal joints. Experimental testing showed failures occurring at jo...

Timber-concrete composite panels are commonly used as a sustainable alternative for reinforced concrete floor construction systems. Their performance also continues to advance with new approaches to interfacial shear connection and layer composition, for example as three-layer sandwich panels with a concrete compressive face layer, timber tensile f...

Origami-inspired metamaterials utilise geometric sheet transformations to generate and control novel material mechanical properties. The majority of research effort has been devoted to straight-crease origami-inspired metamaterials, however curved-crease origami, which allows compliant folding and bending behaviours, has significant potential for a...

Hybrid FRP-timber (HFT) thin-walled sections are high-performance and lightweight wood-based composite structures, developed to meet an increasing societal demand for sustainable construction. This paper proposes an improved modular manufacturing method for HFT thin-walled sections, which inherits advantages of existing manufacturing approaches whi...

Modern factory automation is enabling the economic production of timber building components with sophisticated integral mechanical joints. This paper investigates the governing compressive failure mechanisms of full-length integrally-jointed plywood box columns, and in particular seeks to understand the interaction between localized material knot d...

Pop-up mechanisms are able to generate complex forms from flexible planar materials. They have successfully been used for 3D micro scale engineering applications, but are not yet utilized for building-scale elements due to the difficulty of scaling planar actuation mechanisms. Separately, building elements formed with large, elastic bending deflect...

Multistate origami can achieve multiple design objectives within a single sheet. Separately, curved-crease origami imparts non-zero principal curvature in the sheet during folding, an attribute which designers have utilized for range of applications. This study investigates the intersection of these two pattern families to create multistate curved-...

Curved-crease origami is a subset of origami patterns which induce a curvature into a sheet during folding. This property has led to a number of interesting applications in civil engineering and architecture, however concise geometric parametrisation and precise folded fabrication of such components remains an ongoing challenge. In this paper, the...

Characterisation of the rotational stiffness of fold lines is necessary to analyse the compliant behaviour of origami-inspired structures, however limited data exists for fold lines manufactured from high-strength materials such as steel. This paper establishes a reliable characterisation of perforated steel fold lines, with three improvements to e...

Hybrid timber-concrete (HTC) floor systems are well-suited for prefabricated construction and so have seen widespread use in modern sustainable buildings. This paper investigates a novel extension to such systems by introducing a corrugated core between tensile timber and compressive concrete layers. This new ‘HTCC’ floor panel system is hypothesis...

Concrete-timber composite floor systems have become increasingly popular due to their high sustainability and ease of construction. This paper presents a novel lightweight concrete-timber floor panel system with a fibre reinforced polymer-timber waffle-shaped core between the concrete and timber layers. Digital fabrication techniques and computer-n...

This paper aims to investigate the structural behavior of digitally fabricated thin-walled timber sections with edge connectivity provided by integral mechanical press-fit joints. Experimental, numerical, and analytical investigations have been developed to accurately characterize the press-fit section behavior and their failure modes. Plywood fibe...

This paper presents a detailed geometric design-to-fabrication procedure for a new type of timber sandwich structure that combines a folded assembly method and integral mechanical joints. The paper also investigates the hypothesis that such a combination creates a fast and highly-accurate assembly method for modular timber construction. A digital d...

Hybrid timber-concrete (HTC) floor panels are lightweight and suitable for prefabrication, making them an attractive alternative to conventional reinforced concrete floor systems. The structural stiffness and ultimate strength of HTC systems is heavily dependent upon the level of composite action achieved between timber and concrete layers, with sh...

Curved-crease origami have been utilised as inspiration for numerous engineering applications, however the accuracy of employed manufacturing methods is largely unknown. This paper presents manufacturing methods for two structural sheet materials suitable for use in curved-crease thin-walled structures: typical structural steel and a novel hybrid f...

Generative design methods specify a set of computational rules for the assembly and interaction of geometric elements. Common origami design methods , for example the mirror reflection method, can be considered 'generative' in that they can incrementally generate complex pattern forms from a simpler initial pattern or shape. This paper seeks to dev...

Driven by an increasing demand for sustainable and easy-to-construct timber infrastructure, recent research at The University of Queensland (UQ) has led to the development of a new class of structures called ‘folded hybrid FRP-timber’ (FHFT) structures. In FHFT structures, FRP (fibre reinforced polymer) is combined with timber veneers to create hig...

The increasing interest in timber as a sustainable construction material has led to the development of a new type of structures referred to as ‘hybrid fibre-reinforced polymer–timber thin-walled structures’. In these structures, thin layers of fibre-reinforced polymer are combined with timber veneers to create high-performance, lightweight and easy...

There has been significant recent interest in origami-inspired foldable structures for applications in which transportability and rapid construction are primary design drivers, for example, emergency shelters and staging structures. However, widespread application is not yet seen due to complexities in folded geometry and modelling the structural b...

Several types of tubular, origami-inspired plate mechanisms have been proposed for use as meta-materials and deployable structures. However, research into mechanical properties of these mechanisms is limited to rectilinear forms. This paper investigates the structural feasibility of non-rectilinear rigid-foldable cellular materials for application...

Timber-concrete composite (TCC) floor panels have gained wide acceptance in office and residential construction due to their lightweight, low cost, and low carbonfootprint. A typical TCC floor panel consists of a concrete layer as the compression element and a timber layer as the tensile reinforcement. However, in many of these TCC floor panels, pa...

Origami-inspired engineering design is increasingly used in the development of self-folding structures. The majority of existing self-folding structures either use a bespoke crease pattern to form a single structure, or a universal crease pattern capable of forming numerous structures with multiple folding steps. This paper presents a new approach...

Straight-crease origami crash boxes have previously been designed to possess a near optimum failure mode for a tubular energy-absorbing device. This failure mode, termed a ‘complete diamond mode’ (CDM), possesses a low peak force Pmax and high average force Pavg, caused by generation of travelling hinge lines that propagate laterally during crushin...

The inflation and propagation of a localized instability in elastic tubes shares the same mathematical features with a range of other localization problems, including buckling propagation in long metal tubes under external pressure. Recent research into origami-inspired tubular geometries has suggested that geometric texturing is able to significan...

This paper presents a design-to-fabrication process for folded sandwich structures that comprises surface to pattern conversion, manufacture rationalisation, and integral connection superposition. Folded sandwich structures are shown to possess a tessellated, origami-like structural form in which building component parameters are inherently dependa...

Accordion patterns are widely used for deployable shelters, due to their simple construction, elegant deployment mechanism, and folded plate form with an inherent structural efficiency. This paper proposes two new accordion-type shelters that use modified geometries to improve on the structural stability and stiffness of the typical accordion form....

Folded-core sandwich structures have previously been proposed as lightweight, thin-plate building elements. Such structures typically use a Miura-type core pattern and have an efficient load transfer behaviour, however cannot be used for deployable structures as the attachment of face sheets suppresses any core kinematic behaviours. This limitation...

Rigid-foldable cube-type and eggbox-type kirigami geometries have been of interest for applications including folded-core sandwich panels and deployable structures. Recent studies of these geometry families noticed that their convex pattern vertices enabled several further potential applications that were not otherwise possible with the concave ver...

This paper explores a range of kirigami-inspired folded core structures for use in sandwich panels. Focus has been on assessing the energy-absorption capabilities of the cores, specifically on benchmarking core performance against the widely studied Miura-ori folded core. Four core architectures were investigated. Two cores are based on cube and eg...

Morphing plate-based sandwich mechanisms consist of three layers: an inner core designed to achieve a particular deployed geometric envelope and two outer faces designed to preserve core rigid-foldability from flat-folded to a deployed sandwich form. This paper examines rigid-foldable morphing sandwich mechanisms based on the Miura rigid origami pa...

There exist several kirigami, or non-developable folded plate patterns that share the most useful properties of the widely-used Miura-ori pattern, namely rigid-foldability, a tessellated unit geometry, and constituent elements composed of a single parallelogram plate. This paper first presents parametrisations of five such patterns, two cube-type a...

Curved-crease (CC) origami differs from prismatic, or straight-crease origami, in that the folded surface of the pattern is bent during the folding process. Limited studies on the mechanical performance of such geometries have been conducted, in part because of the difficulty in parametrizing and modeling the pattern geometry. This paper presents a...

A modified planar foldcore geometry was developed by introducing sub-folds into a standard foldcore pattern. It was demonstrated using numerical simulation that the new geometry, deemed the indented foldcore, successfully triggered a high-order travelling hinge line failure mode. This was found to have a much higher and more uniform energy absorpti...

The primary aim of this paper was to manufacture aluminium curved-crease foldcores and assess their behaviour under quasi-static compressive loads, relative to existing straight-crease foldcores and a honeycomb cores. Four foldcore types, standard, indented, and two curved-crease foldcore tessellations, were constructed with comparable density and...

Honeycomb core sandwich shells are used for many applications, but available unit architectures and global curvatures are limited. Numerous origami-core sandwich shells, known as foldcores, have been proposed as alternatives, but studies into their mechanical performance are few. This paper conducts a preliminary investigation into the impact resis...

Miura and Miura-derivative rigid origami patterns are increasingly used for engineering and architectural applications. However, geometric modelling approaches used in existing studies are generally haphazard, with pattern identifications and parameterizations varying widely. Consequently, relationships between Miura-derivative patterns are poorly...

Foldcore sandwich panels have been the focus of much recent study in the aerospace industry. Existing foldcores are composed of a partially folded Miura origami pattern sandwiched between two stiff facings, and have been shown to possess numerous useful properties for impact-resistant applications. Non-Miura origami pattern with similar geometric p...