Author
Keith D. Weiss
Bio: Keith D. Weiss is an academic researcher from Lord Corporation. The author has contributed to research in topics: Magnetorheological fluid & Particle. The author has an hindex of 14, co-authored 24 publications receiving 1440 citations.
Topics: Magnetorheological fluid, Particle, Viscosity, Conductivity, Dielectric
Papers
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TL;DR: In this article, the transition area between elastic and viscous behavior for a conventional ER fluid and a state-of-the-art magneto-rheological (MR) fluid through the use of oscillatory rheometry techniques is examined.
Abstract: This paper examines the transition area between elastic and viscous behavior for a conventional electro-rheological (ER) fluid and a state-of-the-art magneto-rheological (MR) fluid through the use of oscillatory rheometry techniques. A comparison between the yield behavior (strain and stress) measured for these two different types of controllable fluids is presented. The data obtained for MR fluids represents the initial characterization of the pre-yield properties exhibited by this type of material. Finally, a recommendation as to a key area for future R&D is highlighted.
240 citations
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06 Oct 1993TL;DR: A magnetorheological material containing a carrier fluid and an iron alloy particle component can be either an iron-cobalt alloy or an IR-nickel alloy as mentioned in this paper, and the particle component is capable of imparting high yield stress capability.
Abstract: A magnetorheological material containing a carrier fluid and an iron alloy particle component. The particle component can be either an iron-cobalt alloy or an iron-nickel alloy. The iron-cobalt alloy has an iron:cobalt ratio ranging from about 30:70 to 95:5 while the iron-nickel alloy has an iron:nickel ratio ranging from about 90:10 to 99:1. The iron alloy particle components are capable of imparting high yield stress capability to magnetorheological materials.
177 citations
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TL;DR: A summary of the current state of electrorheological (ER) material applications research and development is provided in this paper, where the use of ER materials in a variety of intelligent material systems is covered.
Abstract: This article provides a summary of the current state of electrorheological (ER) material applications research and development. The use of ER materials in a variety of intelligent material systems is covered. A description of basic material configurations used in controllable system components, as well as a discussion of controllable devices such as antivibration mounts, clutches, and dampers, is presented. More recent developments in the area of ER material adaptive structures are then reviewed. Concepts underlying such structures are presented, and models that have been developed to simulate the response of such structures are summarized. Throughout the ar ticle, an attempt is made to identify current and future key areas of research and development in ER material applications technology.
177 citations
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TL;DR: A summary of the current state of electrorheological (ER) material research and development can be found in this paper, where a description of the electorheological effect, a defini cation of obse...
Abstract: This paper provides a summary of the current state of electrorheological (ER) material research and development. In particular, a description of the electrorheological effect, a defini tion of obse...
154 citations
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TL;DR: In this article, a model for controllable fluid dampers is proposed that can effectively portray the behavior of a typical magnetorheological (MR) damper and compared with experimental results for a prototype damper.
Abstract: Semiactive control devices have received significant attention in recent years because they offer the adaptability of active control devices without requiring the associated large power sources. Magnetorheological (MR) dampers are semiactive control devices that use MR fluids to produce controllable dampers. They potentially offer highly reliable operation and can be viewed as fail-safe in that they become passive dampers should the control hardware malfunction. To develop control algorithms that take full advantage of the unique features of the MR damper, models must be developed that can adequately characterize the damper's intrinsic nonlinear behavior. Following a review of several idealized mechanical models for controllable fluid dampers, a new model is proposed that can effectively portray the behavior of a typical MR damper. Comparison with experimental results for a prototype damper indicates that the model is accurate over a wide range of operating conditions and is adequate for control design an...
1,897 citations
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TL;DR: In this paper, the authors provide a concise point of departure for researchers and practitioners alike wishing to assess the current state of the art in the control and monitoring of civil engineering structures, and provide a link between structural control and other fields of control theory.
Abstract: This tutorial/survey paper: (1) provides a concise point of departure for researchers and practitioners alike wishing to assess the current state of the art in the control and monitoring of civil engineering structures; and (2) provides a link between structural control and other fields of control theory, pointing out both differences and similarities, and points out where future research and application efforts are likely to prove fruitful. The paper consists of the following sections: section 1 is an introduction; section 2 deals with passive energy dissipation; section 3 deals with active control; section 4 deals with hybrid and semiactive control systems; section 5 discusses sensors for structural control; section 6 deals with smart material systems; section 7 deals with health monitoring and damage detection; and section 8 deals with research needs. An extensive list of references is provided in the references section.
1,883 citations
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TL;DR: In this paper, a clipped-optimal control strategy based on acceleration feedback for controlling magnetorheological dampers is proposed to reduce structural responses due to seismic loads, and a numerical example, employing a newly developed model that accurately portrays the salient characteristics of the MR dampers, is presented to illustrate the effectiveness of the approach.
Abstract: Control of civil engineering structures for earthquake hazard mitigation represents a relatively new area of research that is growing rapidly. Control systems for these structures have unique requirements and constraints. For example, during a severe seismic event, the external power to a structure may be severed, rendering control schemes relying on large external power supplies ineffective. Magnetorheological (MR) dampers are a new class of devices that mesh well with the requirements and constraints of seismic applications, including having very low power requirements. This paper proposes a clipped-optimal control strategy based on acceleration feedback for controlling MR dampers to reduce structural responses due to seismic loads. A numerical example, employing a newly developed model that accurately portrays the salient characteristics of the MR dampers, is presented to illustrate the effectiveness of the approach.
1,296 citations
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TL;DR: Magnetorheological (MR) fluids, foams and elastomers comprise a class of smart materials whose rheological properties may be controlled by the application of an external magnetic field.
1,104 citations
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TL;DR: A critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures, and improved materials, processing methods, and sensing play an important role in future research.
Abstract: Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.
1,028 citations