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Cellular structures (CSs) have been used extensively in recent years, as they offer a unique range of design freedoms. They can be deployed to create parts that can be lightweight by introducing controlled porous features, while still retaining or improving their mechanical, thermal, or even vibrational properties. Recent advancements in additive m...
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This paper investigates the rolling motion of a spherical top with an axisymmetric mass distribution on a smooth horizontal plane performing periodic vertical oscillations. For the system under consideration, equations of motion and conservation laws are obtained. It is shown that the system admits two equilibrium points corresponding to uniform ro...
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... En estas estructuras, una celda sirve como elemento de volumen representativo del andamio. Es decir, una celda se puede analizar para modificar y optimizar sus propiedades (44,45). Además, en las estructuras periódicas se pueden hacer combinaciones de geometrías de poliedros y variaciones en las dimensiones de las secciones sólidas (tabla 4) para obtener diferentes propiedades (46). ...
Los materiales con una estructura porosa interna que reemplazan hueso dañado y sirven como soporte para procesos regenerativos son una herramienta fundamental en la ingeniería de tejidos óseos. En los últimos años, se ha investigado sobre la geometría interna que deben tener los soportes de modo que respondan a requerimientos específicos. Esta revisión muestra los biomateriales y métodos de manufactura aditiva que se usan en la fabricación de soportes, las principales características geométricas de las celdas que conforman los materiales celulares, las formas que estas celdas se distribuyen en el espacio formando estructuras periódicas o no periódicas respondiendo a métodos de optimización o de generación procedimental, además de la relación entre características geométricas y requerimientos biológicos, mecánicos y de permeabilidad. Se finaliza describiendo, a criterio de los autores, los acuerdos a los que se ha llegado en cuanto a porosidad y tamaño mínimo de poro necesario para regeneración ósea indicando qué otras relaciones entre características y geométricas y requerimientos deben ser estudiados a futuro.
... When holes are introduced with a clear repetitive pattern vs. when holes are introduced with no clear pattern. The sub-category of porous structures that exhibit a repetitive pattern is cellular structures and (Nsiempba et al. 2021) discusses them in detail. A subcategory of cellular structures is lattices. ...
Metal additive manufacturing is gaining immense research attention. Some of these research efforts are associated with physics, statistical, or artificial intelligence-driven process modelling and optimisation, structure–property characterisation, structural design optimisation, or equipment enhancements for cost reduction and faster throughputs. In this review, the focus is drawn on the utilisation of topology optimisation for structural design in metal additive manufacturing. First, the symbiotic relationship between topology optimisation and metal additive manufacturing in aerospace, medical, automotive, and other industries is investigated. Second, support structure design by topology optimisation for thermal-based powder-bed processes is discussed. Third, the introduction of capabilities to limit manufacturing constraints and generate porous features in topology optimisation is examined. Fourth, emerging efforts to adopt artificial intelligence models are examined. Finally, some open-source and commercial software with capabilities for topology optimisation and metal additive manufacturing are explored. This study considers the challenges faced while providing perceptions on future research directions.
... Therefore, if the strain was higher, this structure also be tilted but it was not still similar like orthogonal deformation. The planar deformation continued on the lattice structure [44]. ...
Titanium alloys are widely used for biomedical applications as porous lattice structures whose abilities can be altered via unit cell designs, pore size, and topology. In this study, Ti6Al4V octahedron, star, and dodecahedron cubic and plate lattice structures were designed as 0.20-mm strut diameter with different porosity values (83.06% for octahedron, 53.46% for star, and 63.29% for dodecahedron) and manufactured by laser powder bed fusion. Compression tests were conducted by ISO 13314. The elastic modulus for octahedron, star, and dodecahedron lattices were found 1.7 GPa, 8.6 GPa, and 6.7 GPa, respectively, and results were promising in terms of reducing stress shielding. Relation between relative density and mechanical response was investigated. Chitosan-substituted hydroxyapatite composite coating successfully deposited by electrophoretic deposition on surfaces for biological assessment. Coating increased bioactivity and reduced cell death, especially around implant samples. Chitosan addition ensured an antibacterial effect. Results revealed that mechanical properties and biological responses of structures were affected by the lattice design and pore size.
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... • Biomedical and Biofabrication: the biomedical market represents around 16% of the total AM market share (Wohlers' report). AM can guarantee the realisation of high-complex shapes [4,20] for innovative biomedical implants, organs, and controlled drug delivery systems. Open-source design methodologies can be used to quickly share 3D AM CAD files among researchers [3]. ...
Additive Manufacturing (AM), one of the nine enabling technologies of Industry 4.0, is experiencing rapid growth [...]
... Cellular structures are ordered materials that are constructed by the repetition of a unit cell [14]. The promising properties of these materials are their lightweight construction, higher strength and energy absorption with minimum material consumption. ...
... The acceptance of cellular lattice structure directly relates to the advancements and capabilities of AM processes to create design complexities without increasing manufacturing cost. Hence, it improves the feasibility to manufacture graded parts [14]. Through design complexities of cellular lattice structure, some of the properties of these structures can be influenced directly. ...
Additive manufacturing (AM) has a greater potential to construct lighter parts, having complex geometries with no additional cost, by embedding cellular lattice structures within an object. The geometry of lattice structure can be engineered to achieve improved strength and extra level of performance with the advantage of consuming less material and energy. This paper provides a systematic experimental evaluation of a series of cellular lattice structures, embedded within a cylindrical specimen and constructed according to terms and requirements of ASTMD1621-16, which is standard for the compressive properties of rigid cellular plastics. The modeling of test specimens is based on function representation (FRep) and constructed by fused deposition modeling (FDM) technology. Two different test series, each having eleven test specimens of different parameters, are printed along with their replicates of 70% and 100% infill density. Test specimens are subjected to uniaxial compressive load to produce 13% deformation to the height of the specimen. Comparison of results reveals that specimens, having cellular lattice structure and printed with 70% infill density, exhibit greater strength and improvement in strength to mass ratio, as compared to the solid printed specimen without structure.
Developing a functional gradient scaffold compatible with the fantastic biological and mechanical properties of natural bone tissue is imperative in bone tissue engineering. In this work, the stretch-dominated (cubical and circular) and bending-dominant (diamond and gyroid) pore styles were employed to design custom-graded scaffolds based on the curve interference method and then were fabricated by selective laser sintering (SLS) using polyamide 12 (PA12) powder. Subsequently, the mechanical behavior, failure mechanism, and energy absorption performance of porous structures were investigated via compression experiments and finite element (FE) simulation. The results indicated that the stretch-dominated radial gradient structures entire exhibited transverse shear failure and the bending-dominant radial gradient structures whole exhibited progressive destruction, while all of the axial gradient scaffolds suffered a predictable layer-by-layer fracture. Among them, the bending-dominated radial gradient structure of gyroid had been proven to sustain stronger deformability and energy absorption capacity. Meanwhile, the FE method powerfully predicted the mechanical behavior of the scaffold, and this research thereby possessed significant implications for the development of bone tissue engineering.
It is significant to understand the process and recent trends in additive manufacturing (AM) process, which is evolving and has been in commercial development for more than four decades. Over that time, there has been so many advancements in design methods, materials, manufacturing techniques, and software solutions. Additionally, the AM techniques has been associated with machine connectivity and has automated the workflow in many industries. In this chapter, the working concept of AM technology is illustrated and correlates to the current high potential applications. Further, a comprehensive review converges on AM materials and the recent trend in their development. Eventually, this chapter addresses the research, industrial opportunities, challenges, and limitations with the current market value.
Rapid prototyping or additive manufacturing (AM) techniques are considered the most efficient process for fabrication. It is used to manufacture any intricate shapes with the inputs from 3D CAD data. AM technologies involve layer by layer deposition technique until the entire part is done. Compared to the conventional manufacturing process, many advantages envision the necessity for AM techniques in various aspects like materials, environment, and fabricating methods. As the time for manufacturing is comparatively less for AM techniques, even the design engineer has the freedom to design and test the intricate designs within less time. AM technology is considered green manufacturing that means minimal wastage of materials, and this leads to cost reduction of the final part and most negligible effect on the environment. Using conventional techniques, it is observed that has an adverse effect on the environment, and it's better to switch to alternative methods like AM. This study focusses on how sustainable to use AM techniques in industrial applications and impact the environment using additive techniques. This chapter helps scholars in understanding the sustainability of different additive techniques.
This chapter aims to present in a structured manner different computer‐aided design (CAD) and computer‐aided engineering (CAE) tools, especially developed and applied, when designing for additive manufacturing (AM). These specific tools maximize the capabilities of this technology when developing parts or products for different industries. It is well known that the flexibility of the AM process allows to manufacture complex shapes that are not possible to produce by any other traditional technology. This capability of constructing really complex or organic shapes enables the use of some design strategies like topology optimization (TO) that even though it has existed for decades, it was not frequently applied due to these manufacturing constraints. Also in this chapter, other novel and specific AM design tools like lattice design will be presented. Lattice design or TO demand a highly flexible manufacturing system to be applied and could not be used before, due to the conventional industrial process limitations. In this chapter, an extensive review will be presented starting from the traditional or established design tools (CAD) to more specific and AM‐oriented software, with a complete list of existing options and specific capabilities of each tool.
