A Topological Interlocking Configuration (TIC) is an assembly where the shape and alignment of the blocks define the kinematic constraints. Conventional TICs are single-layered structures made of convex blocks. The interface between the blocks in an assembly is face-to-face contact. The traditional convention disregards the use of joinery, adhesive, or other mechanisms that keep two pieces next to each other. However, TICs require a support structure that prevents the lateral strain of the blocks.<br><br>The generation process of a TIC starts with a surface tessellation that describes a geometric domain. Each tile in the tessellation represents a traversal section of a block. For regular tessellations and uniform generation parameters, such sections lie in the middle of their respective blocks. Additionally, such conditions guarantee the blocks align adequately with each other. If one of such conditions does not hold, then the resultant blocks may not be aligned. Furthermore, there could be overlapping between the blocks, which makes a TIC invalid.<br><br>Traditionally, the generation parameters are angle values set at the edges of the tiles. The angles must match between tiles such that each block in the assembly has a geometry that imposes kinematic constraints to its neighboring blocks. Using the same angle values on regular and semi-regular tessellation produces feasible blocks. That is not the case for non-regular tessellations, curvilinear surfaces, and free-form 3D meshes. In such cases, the generation method must find specific angle values to design the blocks and reduce overlapping.<br><br>In this thesis, we propose a TIC generation framework focused on the generation of valid interlocking assemblies based on multiple types of surface tessellations. We start with the Height-Bisection method, a TIC generation approach that uses the distances from a tile to its respective evolution sections as the generation parameters. The method considers the bisector vectors between two tiles to define the parameters that generate aligned blocks to each other. We expand the generation model to a complete pipeline process that finds feasible generation parameters. The pipeline includes clipping parameters and methods in case that overlapping between blocks cannot be avoided.<br><br>Additionally, we describe a generalization of the mid-section evolution concept to include multiple evolution steps during the generation process. Our approach considers the angles and distances required to generate infinitely many TICs, including shapes that are not possible using the traditional generation method and the Height-Bisection method. Finally, we consider the interlocking assemblies that cannot maintain static equilibrium due to the shape of the surface tessellation. We consider the Structure Feasibility Analysis method to find the location and magnitude of the minimum tension forces that guarantee a TIC will reach a static equilibrium state. We describe how to update the generation parameters according to the results of the feasibility analysis. Our results show that the proposed pipeline generates valid TICs based on different surface tessellations, including closed and free-form shapes.

<div>Architectured material systems offer the ability to control a system's response through the spatial arrangement of material. Material may be connected by discrete linkages or segmented by discrete cuts in such a system. This thesis serves as an investigation of the deformation and load response of architectured material systems in tubular configurations. Specifically, segmented tubes composed of interlocking building blocks and corrugated tubes formed from thin sheets of material are of interest.</div><div> </div><div>Interlocking, segmented tubes, or topologically interlocking material (TIM) tubes, are considered as assemblies of convex polyhedra. Multiple aspect ratios of tubes are considered with identical building block size. The load response to diametral indentation is obtained by finite element analysis and experimentation on additively manufactured tubes. Finite element models consider both an idealized scenario, where contacts between building blocks are stiff, and a realistic scenario, where there are much softer contacts between building blocks and a limit on shear stresses due to friction at contact interfaces. The mechanics of the deformation of TIM tubes are quantified by stress distributions and energies obtained from finite element models. It was found that interlocking between building blocks grants segmented systems increased stiffness, strength, and toughness. The response of TIM tubes varied with tube aspect ratio and contact conditions between blocks. An analysis of thrust-lines in the assembly with finite element results led to the formulation of a model to predict the load response of interlocking, segmented tubes. This model was found to fit idealized FE-model results, and, with the addition of slip between building blocks to the model, experiment results.</div><div> </div><div>Corrugated tubes are considered to be formed from stacks of sheet metal plies. Corrugations are formed one-by-one with a high-pressure fluid and forming machinery. The manufacturing process of these tubes is recreated in a finite element model. With this manufacturing model, the as-formed geometry and residual stress and strain profile of the tube are obtained. Finite element models of corrugated tube loading are created such that their initial state is the result of the manufacturing model. The response of corrugated tubes can then be investigated under the consideration of effects from manufacturing. Including the effects from manufacturing was found to influence the corrugated tube stiffness and yield force. Altering the ply thickness used to form tubes was also found to influence the corrugated tube stiffness. Certain fatigue failure locations were only predicted when including the effects from manufacturing in finite element simulations. Thus, the effects from manufacturing a corrugated tube were found to play a significant role in the tube's load response and failure.</div>

A novel way to ensure stability of mortarless structures – topological interlocking – is examined. In this type of interlocking the overall shape and arrangement of the building blocks are chosen in such a way that the movement of each block is prevented by its neighbours. (The methodological roots of topological interlocking can be found in two ancient structures: the arch and the dry stone wall.) The topological interlocking proper is achieved by two types of blocks: simple convex forms such as the Platonic solids (tetrahedron, cube, octahedron, dodecahedron and icosahedron) that allow plate-like assemblies and specially engineered shapes of the block surfaces that also allow assembling corners. An important example of the latter – so-called Osteomorphic block – is the main object of this research with some insight being provided by numerical modelling of plates assembled from tetrahedra and cubes in the interlocking position. The main structural feature of the interlocking assemblies is the need of the peripheral constraint (for the Osteomorphic blocks this requirement can be relaxed to uni-directional constraint) to keep their integrity. We studied the least visible constraint structure – internal pre-stressed cables which run through pre-fabricated holes in Osteomorphic blocks. It is shown that the pre-stressed steel cables can provide the necessary constraint force without creating appreciable residual stresses in the cables, however the points of connection of the cables are the weakest points and need special treatment. The main mechanical feature of the interlocking structures is the absence of block bonding. As a result, the blocks have a certain freedom of translational and rotational movement (within the kinematic constraints of the assembly) and their contacts have reduced shear stresses which hampers fracture propagation from one block to another. These features pre-determine the specific ways the interlocking assemblies behave under mechanical and dynamic impacts. These were studied in this project and the following results are reported. As the blocks in the interlocking structure are not connected, the main issue is the bearing capacity. The study of the least favourable, central point loading in the direction normal to the structure shows elevated large-scale fracture toughness (resistance to fracture propagation). However when the central force imposes considerable bending the generated tensile membrane stresses assist fracturing of the loaded block. Prevention of bending considerably enhances the strength therefore the most efficient application of the interlocking structures would be in protective coatings and covers. Furthermore, proper selection of the material properties and the interface friction can increase the system overall strength and bearing capacity. The results of the computer simulations suggest that both Young’s modulus and the friction coefficient are the key parameters whose increase improves the bearing capacity of topologically interlocking assemblies.

Ce travail de thèse s'inscrit dans le contexte du développement de la robotique dans la construction. On s’intéresse ici à la construction robotisée de structures maçonnées complexes en ayant recours à de la vision artificielle. La construction sans cintre étant un enjeu important en ce qui concerne la productivité sur un chantier et la quantité de déchets produits, nous explorons, à cet effet, les possibilités qu'offre la rigidité en flexion inhérente aux maçonneries topologiquement autobloquantes. La génération de ces dernières, classique dans le cas plan, est généralisée ici à la conception de structures courbes, à partir de maillages de quadrangles plans et de manière paramétrique, grâce aux logiciels Rhinoceros 3D / Grasshopper. Pour cela, nous proposons un ensemble d'inégalités à respecter afin que la structure obtenue soit effectivement topologiquement autobloquante. Ces inégalités permettent, par ailleurs, d'introduire un résultat nouveau ; à savoir qu'il est possible d'avoir un assemblage de blocs dans lequel chacun des blocs est topologiquement bloqué en translation, mais un sous-ensemble — constitué de plusieurs de ces blocs — ne l'est pas. Un prototype de maçonnerie à topologie autobloquante est finalement conçu. Sa conception repose sur une découpe des joints d'inclinaison variable qui permet de le construire sans cintre. En parallèle, nous abordons des aspects de vision artificielle robuste pour un environnement chantier, environnement complexe dans lequel les capteurs peuvent subir des chocs, être salis ou déplacés accidentellement. Le problème est d'estimer la position relative d'un bloc de maçonnerie par rapport à un bras robot, à partir de simples caméras 2D ne nécessitant pas d'étape de calibration. Notre approche repose sur l'utilisation de réseaux de neurones convolutifs de classification, entraînés à partir de centaines de milliers d'images synthétiques de l’ensemble bras robot + bloc, présentant des variations aléatoires en terme de dimensions et positions du bloc, textures, éclairage, etc, et ce afin que le robot puisse apprendre à repérer le bloc sans trop de biais d’environnement. La génération de ces images est réalisée grâce à Unreal Engine 4. Cette méthode permet la localisation du bloc par rapport au robot avec une précision millimétrique, sans utiliser une seule image réelle pour la phase d'apprentissage ; ce qui constitue un avantage certain puisque l'acquisition de données représentatives pour l'apprentissage est un processus long et fastidieux. Nous avons également construit une base de données riche, constituée d’environ 12000 images réelles contenant un robot et un bloc précisément localisés, permettant d’évaluer quantitativement notre approche et de la rendre comparable aux approches alternatives. Un démonstrateur réel intégrant un bras ABB IRB 120, des blocs parallélépipédiques et trois webcams a été mis en place pour démontrer la faisabilité de la méthode / The context of this thesis work is the development of robotics in the construction industry. We explore the robotic construction of complex masonry structures with the help of computer vision. Construction without the use of formwork is an important issue in relation to both productivity on a construction site and the amount of waste generated. To this end, we study topological interlocking masonries and the possibilities they present. The design of this kind of masonry is standard for planar structures. We generalize it to the design of curved structures in a parametrical way, using PQ meshes and the softwares Rhinoceros 3D and Grasshopper. To achieve this, we introduce a set of inequalities to respect in order to have a topological interlocked structure. These inequalities allow us to present a new result. Namely, it is possible to have an assembly of blocks in which each block is interlocked in translation, while having a subset — composed of several of these blocks — that is not interlocked. We also present a prototype of topological interlocking masonry. Its design is based on variable inclination joints, allowing construction without formwork. In parallel, we are studying robust computer vision for unstructured environments like construction sites, in which sensors are vulnerable to dust or could be accidentally jostled. The goal is to estimate the relative pose (position + orientation) of a masonry block with respect to a robot, using only cheap cameras without the need for calibration. Our approach relies on a classification Convolutional Neural Network trained using hundreds of thousands of synthetically rendered scenes with a robot and a block, and randomized parameters such as block dimensions and poses, light, textures, etc, so that the robot can learn to locate the block without being influenced by the environment. The generation of these images is performed with Unreal Engine 4. This method allows us to estimate a block pose very accurately, with only millimetric errors, without using a single real image for training. This is a strong advantage since acquiring representative training data is a long and expensive process. We also built a new rich dataset of real robot images (about 12,000 images) with accurately localized blocks so that we can evaluate our approach and compare it to alternative approaches. A real demonstrator, including a ABB IRB 120 robot, cuboid blocks and three webcams was set up to prove the feasibility of the method

<p>  </p> <p>Architectured materials offer engineers more options for choosing materials with their desired properties. Segmenting materials to create topological interlocking materials (TIMs) creates materials, which can deform in greater amounts without failure and absorb more strain energy. Previous research on TIMs has shown that the stiffness and reaction force of these materials can be directly controlled by controlling the boundary forces offered by the frame which constrains these materials.</p> <p>The research presented in this paper investigated a TIM made into a 1-Dimension beam like structure called a lintel. This research investigated not only the mechanics of this structure, but also developed a method of directly controlling the reaction force at a given displacement using shape memory alloy (SMA) wires. These wires would actuate the boundary pieces used to constrain the system. These actuation wires coupled with force sensors imbedded into the lintel allowed a feedback control loop to be established, which would control the reaction force. The reaction force was then controlled to create a smart structure which could optimize the strain energy absorption under the constraint of a maximum allowable load, similar to cellular solids used in packaging and padding materials.</p> <p>To develop this smart structure, four separate investigations occurred. The first was finite element analysis (FEA) performed to model the loading response of the lintel. This experiment demonstrated that the Mises Truss Model was effective at modelling the lintel. The second was an experimental validation of the FEA model performed in the first investigation. This experiment validated the Mises Truss Model for the lintel. The third investigation simulated the active lintel using computational software and the model of the lintel established in the first two investigations. This experiment demonstrated computationally the ability of SMA wires to control the reaction force as desired in an idealized case. The fourth and final investigation experimentally validated the ability to create and active lintel and created a functioning prototype. This demonstrated experimentally the ability of the active lintel to control reaction force as desired.</p> <p>This project has demonstrated the viability to create smart structures using segmented materials, which in the future may be used in a variety of applications including robotics and adaptive structures in harsh environments. </p>