CDRsp - Comunicações em conferências internacionais
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- Global optimization framework for solar building designPublication . Silva, N.; Alves, N.; Pascoal-Faria, P.The generative modeling paradigm is a shift from static models to flexible models. It describes a modeling process using functions, methods and operators. The result is an algorithmic description of the construction process. Each evaluation of such an algorithm creates a model instance, which depends on its input parameters (width, height, volume, roof angle, orientation, location). These values are normally chosen according to aesthetic aspects and style. In this study, the model’s parameters are automatically generated according to an objective function. A generative model can be optimized according to its parameters, in this way, the best solution for a constrained problem is determined. Besides the establishment of an overall framework design, this work consists on the identification of different building shapes and their main parameters, the creation of an algorithmic description for these main shapes and the formulation of the objective function, respecting a building’s energy consumption (solar energy, heating and insulation). Additionally, the conception of an optimization pipeline, combining an energy calculation tool with a geometric scripting engine is presented. The methods developed leads to an automated and optimized 3D shape generation for the projected building (based on the desired conditions and according to specific constrains). The approach proposed will help in the construction of real buildings that account for less energy consumption and for a more sustainable world.
- Two emerging innovative dragons: An analysis of the IPR strategy of China's Huawei and ZTEPublication . Godinho, Manuel Mira; Ferreira, VítorChina has been experiencing a historical take-off iin its use of intellectual property rights (IPR). This paper discusses the IPR strategy of two leading high-tech Chinese firms, Huawei and ZTE, analyzing how they are moving to global leadership in the telecom equipment market. Specifically, the paper addresses their IPR performance with respect to patenting and trademark registration in the most relevant global IPR systems. By 2008 Huawei had already reached world leadership in the international PCT patents applicants’ ranking, while in 2011 Huawei was substituted by ZTE in that position (with Huawei dropping to 3rd place). The paper shows how both firms have developed dynamic capabilities in innovation by investing strongly in R&D. This investment has reflected in a dramatic growth of patent applications. Even if a direct correlation between patent applications and capacity to innovate is not assumed, the growing demand for patents (and more recently trademarks) in different IPR systems reveals an aggressive technological and commercial stance of both firms on the global market.
- A study on the mouldability of technical parts using hybrid moulds and structural foamsPublication . Nogueira, A. A.; Martinho, P. G.; Brito, A. M.; Pouzada, A. S.The production of large plastics parts in small series by injection moulding requires the devel-opment of a new concept of moulds that allows an economic production. This type of products is applied in urban furniture, automotive, nautical and aerospace industries. The use of alternative methodologies for de-sign and manufacturing in a current stage in Portugal gave rise to the concept of hybrid mould. The control and monitoring of the injection moulding process is essential to evaluate the reproducibility of the mouldings and to obtain a product with good quality. Thus the injection mould, which has a significant influence on the final part, must be carefully designed.
- Robust STL processing for extrusion-based manufacturingPublication . Gaspar, M.B.; Martins-Ferreira, N.The slicing and tool-path generation are two fundamental processing steps in rapid prototyping/rapid manufacturing (RP/RM), as well as in CAM. Nevertheless, the specific requirements of the diverse RP/RM techniques are not always addressed by existing tools for CAM. We present a set of efficient and robust algorithms for processing STL files in RP/RM.
- Polycaprolactone-based scaffold plus BMP-2 in a sheep thoracic spine fusion modelPublication . Yong, M.; Melchels, F.; Vaquette, C.; Hutmacher, D.; Adam, C.; Domingos, M.; Bártolo, P.We report the application of a novel scaffold design in a sheep thoracic spine model for spine deformity correction. The combination of the calcium-phosphate coated polycaprolactone scaffolds with recombinant human bone morphogenic protein-2 are intended as a future bone graft substitute in ensuring the stability of bony intervertebral fusion. A solid free-form fabrication process based on melt extrusion has been utilized in the manufacturing of these scaffolds.
- Polymers, Biomanufacturing and Regenerative MedicinePublication . Mitchell, Geoffrey R.; Domingos, M.; Bártolo, Paulo J.Polymers have a major contribution to make in the field of regenerative medicine in order to develop and deploy biological substitutes that restore, maintain, or improve tissue function. There are realistic opportunities to create tissues using an engineered extracellular matrix or scaffold and biologically active molecules. A number of different approaches to preparing scaffolds have been explored and the requirements for materials and personalization identified. We review the methodologies and materials available and report on recent work at the CDRSP to integrate and provide control of the processes to provide a realistic biomanufacturing process.
- Maximizing the placement of congruent polyhedrain a parallelepiped containerPublication . Gaspar, M. Belbut; Martins-Ferreira, N.Given multiple identical polyhedral objects and a parallelepiped container, how should one place the objects so that the largest number fits inside the container? This simple question is important in many applications, yet the answer is elusive. In fact, we know of no published solution for this very general formulation. Still, in many circumstances, further restrictions apply, resulting in a large number of variations requiring different algorithmic strategies. In this presentation we will further formalize the problem, present some of its many variations, and in particular one that applies to the stereolithographic rapid prototyping technology.
- Preface of the "Symposium on integrated computational tools for advanced manufacturing"Publication . Alves, NunoThe Symposium on Integrated Computational Tools for Advanced Manufacturing, held within 10th International Conference of Numerical Analysis and Applied Mathematics, Kos, Greece, from September 19 to 25, 2012, is a relevant forum for the scientific exchange of multidisciplinary issues related to integrated computational tools for advanced manufacturing. The symposium contains eight reviewed papers, covering important research topics, such as multidisciplinary optimization, numerical modelling, computer-aided design, computer-aided engineering and additive manufacturing technologies.
- Optimalmould-part I: Multi-objective optimization to moulds design for injection of polymersPublication . Ramos, Carina; Carreira, P.; Bártolo, Paulo; Alves, NunoThe problem of mould design optimisation for polymer injection is a key issue for both mouldmaking and polymer injection industries. Several computational tools have proposed to address this problem. However they do not cover all aspects related to both mould design and injection moulding process, usually requiring the geometrical configuration of the initial mould solution. This paper presents a novel multi-objective optimisation tool, integrating CAD and CAE tools to optimise mould design parameters and injection moulding process parameters. No initial geometric definition of the mould is required. An industrial case study was considered to validate the proposed approach and the performance of several optimisation algorithms evaluated.
- Thermo-kinetic curing model for stereolithographic applicationsPublication . Bártolo, PauloA thermal-kinetic model, using the finite element method to study, simulate and optimise stereolithography, is presented in this paper. The model, which is theoretically rigorous and practical in its implementation, describes both the heat transfer effects and the course of the chemical reaction. This model includes the effects of photo-initiator concentration, temperature and light intensity, predicting the diffusion-controlled effects that occur after vitrification, the phenomenon of unimolecular termination and the shrinkage effects. Light intensity values at the resin surface are defined by assuming an appropriated Gaussian intensity distribution. The Beer-Lambert law enables to describe the decrease in light intensity with depth. The non-linear variation of the glass transition temperature with fractional conversion can be determined and consequently the mechanical behaviour of the resin sample predicted.