Untitled

Funder

Organizational Unit

Publications

Properties and numerical modeling of MR dampers

Publication . Barros, Rui; Braz-César, Manuel

Among the different strategies available to control engineering vibrations, the semi-active contrai based on Magnetorheological (MR) dampers have become a promising technology to be used in civil engineering stmctures. The ability of these devices to change the stmctural behavior without the need of large power sources is a major advantage that can be used to justify their potential application to this engineering branch. This paper reviews the basic concept of MR fluids and provides an insight of MR dampers dynamic behavior and the available numerical procedures to describe the damper response. In the first section an overview of the basic properties of the MR fluids and the fluid behavior under different flow regimes are presented. Then, a selection of numerical models to simulate MR dampers behavior will be presented based on the available literature.

2012Conference object

Open access

Experimental behaviour and numerical analysis of dampers MR dampers

Publication . Braz-César, Manuel; Barros, Rui

This paper presents the results of an experimental and numerical analysis developed to study the non-linear hysteretic behavior of MR dampers. In the first section a brief review of the numerical models available to simulate their behavior will be presented. To obtain and analyze the hysteretic behavior of MR dampers, a device was experimentally tested under several input excitations. Based on the experimental results an identification procedure was carried out to determine the parameters that are necessary to develop a numerical model. Finally, results from experimental investigations and numerical analyses are summarized and compared.

2012Conference object

Open access

Numerical modeling of magneto-rheological dampers

Publication . Braz-César, Manuel; Barros, Rui

Entre as diferentes estratégias disponíveis para controlar vibrações em engenharia, o controlo semi-activo com base em amortecedores magnetoreológico (MR) tornaram-se uma tecnologia promissora para ser utilizada em estruturas de engenharia civil. A capacidade destes dispositivos para alterar o comportamento estrutural, sem a necessidade de alimentação por grandes fontes de energia, é uma grande vantagem que pode ser usada para justificar o seu potencial de aplicação para este ramo de engenharia. Este trabalho aborda o conceito básico de fluidos MR e fornece uma visão do comportamento dinâmico de amortecedores MR, bem como dos procedimentos numéricos disponíveis para descrever a resposta do amortecedor. A partir de uma visão geral das propriedades básicas dos fluidos MR, é apresentado o comportamento do fluido sob regimes diferentes de fluxos. Em seguida, com base na literatura disponível, detalha-se a seleção de modelos numéricos para simular o comportamento de amortecedores MR.

2013Journal article

Open access

Passive control of civil engineering structures

Publication . Braz-César, Manuel; Barros, Rui

Structural control has been a major research area i n aerospace engineering aimed at solving very complex problems related with analysis and des ign of flexible structures. The efficiency of these strategies to improve the performance of s everal structural systems suggests its potential to reduce damage and control earthquake4i nduced response in civil structures. Therefore, this technology has been well accepted b y structural engineers as a feasible approach to design improved earthquake resistant st ructures. The present paper provide a brief description of each control scheme describing the m ain properties of different anti4seismic solutions and presenting the most relevant developm ents in this area. Control methodologies and devices are highlighted identifying their advan tages and limitations. The main focus of this paper is to present a comprehensive state4of4t he4art of passive control system. Different passive techniques are described and the effectiven ess in mitigating seismic hazard for structures is addressed.

2013Conference object

Open access