970 resultados para Engineer
Resumo:
Com o passar dos anos a engenharia estrutural passou a lidar com a exigência cada vez maior de estruturas que ocupem menos espaço e sejam consideravelmente mais leves. No caso de passarelas de pedestres, a esbeltez da estrutura aliada a um baixo peso pode acarretar em problemas de vibrações devido à ressonância com o caminhar dos pedestres. Estes problemas podem variar desde uma simples sensação de desconforto até problemas mais graves como o colapso estrutural. Com base nestas premissas, esta dissertação visa investigar dois modelos estruturais, um em concreto armado e outro misto, do tipo aço concreto, onde os modelos serão estudados mediante o emprego do método dos elementos finitos através do programa ANSYS. Os modelos numéricos permitem determinar as frequências naturais da estrutura e consequentemente estudar as respostas dos modelos mediante análises de vibrações forçadas. As respostas dinâmicas da estrutura serão obtidas em termos dos valores dos deslocamentos máximos e das acelerações de pico. Os resultados obtidos foram comparados com os principais guias que regem o conforto humano no caso de caminhar de pessoas em passarelas de pedestres, de forma que houve indicativos de possíveis desconfortos após a análise dos resultados obtidos ao longo da investigação. Finalmente, foi feito um estudo considerando-se movimentos aleatórios dos pedestres sobre as passarelas, objetivando estudar os níveis da resposta dinâmica das estruturas nestas situações.
Resumo:
Model Predictive Control (MPC) represents a major paradigm shift in the field of automatic control. This radically affects synthesis techniques (illustrated by control of an unstable system) and underlying concepts (illustrated by control of a multivariable system), as well as lifting the control engineer's focus from prescriptions to specifications ('what' not 'how', illustrated by emulation of a conventional autopilot). Part of the objective of this paper is to emphasize the significance of this paradigm shift. Another part is to consider the fact that this shift was missed for many years by the academic community, and what this tells us about teaching and research in the field.
Resumo:
A framework has been developed for the UK economy that categorizes companies who provides a more defined perspective on the structure of the economy in order to help decision makers, government and industry to achieve sustained economic growth. The Institute for Manufacturing (IfM) has established a broader definition of manufacturing that equates manufacturing to the full cycle of activities from research and development, through design, production, logistics and services, to end of life management, within an economic and social context. This approach recognizes that manufacturing firms turn ideas into products and services and that they are inventors, innovators, global supply chain managers and service providers. It is hoped that this categorization provides policy-makers with a clear frame of reference for discussing measures to adapt interventions to address the needs of the diverse set of companies.
Resumo:
The complex, fragmented and diverse aspects of a sustainable development perspective are translated into an eight-point framework that defines a problem boundary larger than that traditionally adopted by civil engineers. This leads to practical questions intended to inform engineers who ask 'am I being sustainable?' during project implementation. The value of the questions is tested against a case history of a wastewater treatment project. This demonstrates the relevance of the questions to successive project delivery phases of defining the problem, choosing a solution and implementing that solution through design, construction and operation. The case history highlights that answers to several of the additional questions raised by considering this wider problem space are currently buried within government and clients' policies, regulations and standard practice; these answers may not be accessible to the professional engineer.