Developments on code-compliant Topology Optimisation methodologies for the steel construction industry have recently been proposed. Also, it has been found that topologically optimised steel bolted connection parts – which behave non-linearly to a very significant degree of damage – do not waive physically non-linear analyses to assess an ultimate capacity that can be lower than what is predicted by the optimisation procedure linear analyses. These two circumstances brought urgency to the experimental testing of such optimised parts. The herein depicted experimental programme assessed topologically optimised and previously numerically analysed bolted parts of a well-known steel connection. The results allowed redefining the material trilinear model to be used in further numerical analysis and, very significantly, validated the numerical simulations results as well as the application of Eurocode formulae for connections component resistance. The difference between the previous numerically predicted ultimate resistance and the experimentally defined did not exceed 2.6%.

Testing shear-resisting plates in steel connections is one of the most challenging laboratory undertakings in steel construction, as the most common experimental layout design includes simulating the connection with its adjoining members. This significant hindrance gained particular magnitude as the need to test prototypes of topologically optimised shear cover plates became more pressing. Indeed, new code-compliant topology optimisation approaches for steel construction have recently been offered, and physically non-linear analyses have been demonstrated to be vital for assessing these elements. Hence, a rapid and reliable experimental process has become a fundamental necessity. To answer this need, a novel layout is herein proposed, in which topologically optimised and previously numerically examined bolted shear plates of a well-known steel joint were tested. The results allowed for the definition of the material trilinear model for use in subsequent numerical analysis, as well as the validation of the numerical simulation results. The discrepancy between the previously mathematically anticipated and empirically determined ultimate resistance did not exceed 1.7%.

The main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibility in tailoring properties is employed frequently to design functionally-graded materials. Topology optimisation methods are powerful tools to functionally graded materials design with cellular structure geometry, although continuity between adjacent unit-cells in gradient directions remains a restriction. It is mandatory to attain a manufacturable part to guarantee the connectedness between adjoining microstructures, namely by ensuring that the solid regions on the microstructure’s borders i.e., kinematic connectors) match the neighboring cells that share the same boundary. This study assesses the kinematic connectors generated by imposing local density restrictions in the initial design domain (i.e., nucleation) between topologically optimised representative unit-cells. Several kinematic connector examples are presented for two representatives unit-cells topology optimised for maximum bulk and shear moduli with different volume fractions restrictions and graduated Young’s modulus. Experimental mechanical tests (compression) were performed, and comparison studies were carried out between experimental and numerical Young’s modulus. The results for the single maximum bulk for the mean values for experimental compressive Young’s modulus (Ex¯ ) with 60%Vf show a deviation of 9.15% . The single maximum shear for the experimental compressive Young’s modulus mean values (Ex¯ ) with 60%Vf , exhibit a deviation of 11.73% . For graded structures, the experimental mean values of compressive Young’s moduli (Ex¯ ), compared with predicted total Young’s moduli (ESe ), show a deviation of 6.96 for the bulk graded structure. The main results show that the single type representative unit-cell experimental Young’s modulus with higher volume fraction presents a minor deviation compared with homogenized data. Both (i.e., bulk and shear moduli) graded microstructures show continuity between adjacent cells. The proposed method proved to be suitable for generating kinematic connections for the design of shear and bulk graduated microstructured materials.

Advanced manufacturing techniques are being explored to fabricate degradable and non-degradable, porous or non-porous implants for medical applications. These implants have been designed using standard computer-aided design (CAD) and computer-aided engineering (CAE) tools and produced in a multitude of materials. The recent use of optimisation tech niques, mainly topology optimisation, allows the development of additive manufactured medical devices with improved performance. This review discusses the combined use of optimisation techniques and additive manufacturing to produce biocompatible and biodegradable scafolds for tissue engineering with improved mechanical and permeability properties; metallic lattice structures with reduced weight and minimal stress shielding efect; and lightweight personalised orthopae dic implants. Three optimisation routes are considered: topology optimisation; triply periodic minimal surfaces that can be manipulated by means of the equations parameters to optimise the overall performance; and the use of repetitive structures that are optimised as unit cells under certain conditions to compose a bulk object. Major limitations and research challenges are highlighted and discussed.

Atualmente, existe necessidade de materiais inovadores, com novas propriedades, capazes de conferir desempenho superior aos componentes e sistemas. Os materiais sólidos contínuos apresentam propriedades fortemente dependentes dos seus constituintes base. Contudo, com o desenvolvimento dos metamateriais nas últimas décadas, dá origem a uma nova classe de materiais com novas propriedades que resultam da sua microestrutura interna. Os metamateriais mecânicos, especificamente, são uma categoria de materiais celulares cujas propriedades mecânicas são obtidas pela distribuição ótima do material. O principal objetivo deste trabalho é a produção de metamateriais mecânicos através de Fabrico digital direto, estabelecendo relações entre a conceção por intermédio de ferramentas computacionais, a tecnologia de fabrico e a validação experimental. A metodologia utilizada aplica o método numérico de otimização topologia SIMP e explora a conjugação de diferentes restrições de densidade e forças aplicadas nas soluções inicias com os parâmetros de otimização na conceção de microestruturas ótimas. A homogeneização numérica, é utilizada para estimar as propriedades mecânicas das microestruturas otimizadas. Através da fabricação aditiva por Material Jetting as microestruturas ótimas são produzidas sendo posteriormente sujeitas a ensaios mecânicos. As microestruturas obtidas pela metodologia proposta possuem propriedades mecânicas diversas. As propriedades mecânicas experimentais à tração, compressão e corte são inferiores às homogeneizadas e dependentes do tamanho de escala e da fração volúmica de material sólido empregue nos provetes. Sendo os desvios do módulo de Young e de elasticidade transversal inversamente proporcional como aumento da escala e frações volúmicas dos provetes. Apesar das diferenças entre as propriedades homogeneizadas e as experimentais estarem de acordo com o pressuposto de periodicidade assumida nos métodos de homogeneização, existem outros fatores que podem influenciar estes desvios como, o tipo e tamanho de malha empregue na discretização do domínio, o tamanho dos provetes e as condições de fronteira e carregamentos impostos, especificidades do processo produtivo e dos materiais empregues. Este trabalho conclui que a metodologia aplicada é válida para a conceção e produção de metamateriais mecânicos por fabricação aditiva e que as propriedades experimentais destes produzidos por Material Jetting são inferiores às homogeneizadas.

The main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibility in tailoring properties is employed frequently to design functionally-graded materials. Topology optimisation methods are powerful tools to functionally graded materials design with cellular structure geometry, although continuity between adjacent unit-cells in gradient directions remains a restriction. It is mandatory to attain a manufacturable part to guarantee the connectedness between adjoining microstructures, namely by ensuring that the solid regions on the microstructure’s borders i.e., kinematic connectors) match the neighboring cells that share the same boundary. This study assesses the kinematic connectors generated by imposing local density restrictions in the initial design domain (i.e., nucleation) between topologically optimised representative unit-cells. Several kinematic connector examples are presented for two representatives unit-cells topology optimised for maximum bulk and shear moduli with different volume fractions restrictions and graduated Young’s modulus. Experimental mechanical tests (compression) were performed, and comparison studies were carried out between experimental and numerical Young’s modulus. The results for the single maximum bulk for the mean values for experimental compressive Young’s modulus (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>) with 60<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>%</mo><mspace width="3.33333pt"></mspace><msub><mi>V</mi><mi mathvariant="normal">f</mi></msub></mrow></semantics></math></inline-formula> show a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>9.15</mn><mo>%</mo></mrow></semantics></math></inline-formula>. The single maximum shear for the experimental compressive Young’s modulus mean values (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>) with 60<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>%</mo><mspace width="3.33333pt"></mspace><msub><mi>V</mi><mi mathvariant="normal">f</mi></msub></mrow></semantics></math></inline-formula>, exhibit a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>11.73</mn><mo>%</mo></mrow></semantics></math></inline-formula>. For graded structures, the experimental mean values of compressive Young’s moduli (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>), compared with predicted total Young’s moduli (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mi>Se</mi></msup></semantics></math></inline-formula>), show a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.96</mn></mrow></semantics></math></inline-formula> for the bulk graded structure. The main results show that the single type representative unit-cell experimental Young’s modulus with higher volume fraction presents a minor deviation compared with homogenized data. Both (i.e., bulk and shear moduli) graded microstructures show continuity between adjacent cells. The proposed method proved to be suitable for generating kinematic connections for the design of shear and bulk graduated microstructured materials.

The present work initially focuses on the numerical analysis of a plate, addressing the objectives and constraints required to achieve a truss structure through Topology Optimisation analysis. After this, validation was essential, resulting in promising results. Additional studies, such as linear buckling analysis, were performed to improve the performance and efficiency of the truss. Subsequently, the first step towards the implementation of the Digital Twin concept involved structural monitoring using a digital indicator to facilitate the early identification of problems and ensure the accurate acquisition of input and output data. This approach also allows a detailed analysis of the true response of the structure to various loads and conditions. Before implementing the code for the Digital Twin application, an experimental analysis was performed, comparing the results with the numerical simulations. This comparison revealed discrepancies in the values for simple numerical cases, attributed to excessive stiffness of the structure. And very good results for a more complete simulation, with relative errors below 15%. Finally, a comprehensive workflow was developed to illustrate the integration of all discussed topics, ensuring effective implementation of the Digital Twin concept.