Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review

Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed

From 3D Models to 3D Prints: an Overview of the Processing Pipeline

Due to the wide diffusion of 3D printing technologies, geometric algorithms for Additive Manufacturing are being invented at an impressive speed. Each single step, in particular along the Process Planning pipeline, can now count on dozens of methods that prepare the 3D model for fabrication, while analysing and optimizing geometry and machine instructions for various objectives. This report provides a classification of this huge state of the art, and elicits the relation between each single algorithm and a list of desirable objectives during Process Planning. The objectives themselves are listed and discussed, along with possible needs for tradeoffs. Additive Manufacturing technologies are broadly categorized to explicitly relate classes of devices and supported features. Finally, this report offers an analysis of the state of the art while discussing open and challenging problems from both an academic and an industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and Innovation action; Grant agreement N. 68044

Review of research in feature-based design

Research in feature-based design is reviewed. Feature-based design is regarded as a key factor towards CAD/CAPP integration from a process planning point of view. From a design point of view, feature-based design offers possibilities for supporting the design process better than current CAD systems do. The evolution of feature definitions is briefly discussed. Features and their role in the design process and as representatives of design-objects and design-object knowledge are discussed. The main research issues related to feature-based design are outlined. These are: feature representation, features and tolerances, feature validation, multiple viewpoints towards features, features and standardization, and features and languages. An overview of some academic feature-based design systems is provided. Future research issues in feature-based design are outlined. The conclusion is that feature-based design is still in its infancy, and that more research is needed for a better support of the design process and better integration with manufacturing, although major advances have already been made

Using Computer Technology Tools to Improve the Teaching-Learning Process in Technical and Vocational Education: Mechanical Engineering Subject Area

This paper discusses the integration of computer assisted instructions (CAI) with traditional class room teaching. It describes a teaching method to bring real-world of industrial work into the classroom that underscores the need to learn fundamental principles while adding excitement and relevance to the experience. This paper presents results of a case study undertaken to understand the effect of computer assisted teaching methodology on learning effectiveness in classroom environment. The effects of computer assisted instructions on different levels of cognition of individual learners have also been evaluated. The computer aided drawing (CAD), computer aided manufacturing (CAM) and computer numerical control (CNC) courses at the Bahrain institute are an integral part of this attempt. These courses emphasize the development of a 3-D geometric computer model and application of this digital database to all phases of the design process. The students make freehand sketches, build computer models, mate assemblies of parts, perform various analysis, create kinematics simulations, generate final design drawings, import engineering drawing as DXF file, generate NC file to build rapid prototypes as shown in the table 1 below. Keywords: Computer Technology, C.N.C and AutoCad Softwar

Integration of magnetic amplifier switch model into computer aided design for power converters

Зазвичай у джерелах вторинного електроживлення (ДВЕЖ) комутаційну та регулюючу функції виконують напівпровідникові компоненти. Однак вони не можуть забезпечити високу якість вихідних характеристик у багатоканальних джерелах живлення та в ДВЕЖ із високим рівнем струму навантаження. В таких випадках як силові ключі використовують високочастотні магнітні підсилювачі (ВМП) на основі аморфних магнітом’яких сплавів з прямокутною петлею гістерезису. Розроблення перетворювачів електроенергії на основі ВМП не є повністю автоматизованим. ВМП є магнітним компонентом з нелінійними властивостями. Системи автоматизованого проектування (САПР) для комп’ютерного імітаційного моделювання електричних кіл не призначені для розрахунків магнітних полів та працюють з дискретними електричними компонентами. Існує проблема інтеграції моделі компонента з магнітним гістерезисом у бібліотеку моделей САПР. Крім того, досить складно оцінити оптимальні параметри такого компонента. У статті запропоновано нову математичну модель силового ключа на основі ВМП, що ґрунтується на функції, яку можна генерувати з допомогою цифрових технологій. Досліджено цифровий генератор синуса, що складається з цифрових дискретних компнентів для моделювання силового ключа на основі ВМП. Запропоновану математичну модель силового ключа на основі ВМП інтегровано у САПР. Проведено комп’ютерне імітаційне моделювання електричного кола, що містить ВМП. Розраховано абсолютну похибку та середньоквадратичне відхилення моделі процесів перемагнічення ВМП у порівнянні з експериментально отриманими даними. Така часткова автоматизація процесу розроблення високочастотних перетворювачів електроенергії на основі ВМП суттєво зменшить його складність, тривалість і вартість, а також сприятиме розвиткові нових схемотехнічних рішень.The designing of electrical power converters based on Magnetic Amplifier (MagAmp) switches is not fully automated. MagAmp is a magnetic component with nonlinear properties. Computer aided design (CAD) programmes are built to simulate electric circuits without electromagnetic field with distributed components. There is a problem of integration of a model of a component with magnetic hysteresis into the set of CAD models. In addition, estimation of the optimal parameters of such a component is rather complicated. The article proposes a new model of MagAmp switch which is based on a function that can be generated using digital technology. The digital generator of sinusoidal signals, consisting of discrete digital components for modeling the MagAmp switch, is investigated. Integration of the model into CAD programme and simulation of the electric circuit, which includes MagAmp switch, are obtained. Partial automation will reduce complexity, duration and cost of the design procedure, and will enhance the development of power converters

Computer-Aided Conceptual Design Through TRIZ-based Manipulation of Topological Optimizations

Organised by: Cranfield UniversityIn a recent project the authors proposed the adoption of Optimization Systems [1] as a bridging element between Computer-Aided Innovation (CAI) and PLM to identify geometrical contradictions [2], a particular case of the TRIZ physical contradiction [3]. A further development of the research has revealed that the solutions obtained from several topological optimizations can be considered as elementary customized modeling features for a specific design task. The topology overcoming the arising geometrical contradiction can be obtained through a manipulation of the density distributions constituting the conflicting pair. Already two strategies of density combination have been identified as capable to solve geometrical contradictions.Mori Seiki – The Machine Tool Compan

Computational fluid dynamics model of a quad-rotor helicopter for dynamic analysis

The control and performance of a quad-rotor helicopter UAV is greatly influenced by its aerodynamics, which in turn is affected by the interactions with features in its remote environment. This paper presents details of Computational Fluid Dynamics (CFD) simulation and analysis of a quadrotor helicopter. It starts by presenting how SolidWorks software is used to develop a 3-D Computer Aided Design (CAD) model of the quad-rotor helicopter, then describes how CFD is used as a computer based mathematical modelling tool to simulate and analyze the effects of wind flow patterns on the performance and control of the quadrotor helicopter. For the purpose of developing a robust adaptive controller for the quad-rotor helicopter to withstand any environmental constraints, which is not within the scope of this paper; this work accurately models the quad-rotor static and dynamic characteristics from a limited number of time-accurate CFD simulations

Application of an expert system shell in the preliminary design of offshore supply vessels

This paper presents the application of expert system programming in preliminary ship design with particular emphasis on offshore supply vessels. Instead of using one of the conventional programming expert system languages, the system is developed using an expert system shell, Leonardo. The design program is written in such a way that it is user friendly as well as giving the user full control over the progress of the design. The algorithms developed in this system are based on extensive research on existing offshore supply vessels