18 research outputs found

    Adaptive and active materials: Selected papers from the ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS 10) (Philadelphia, PA, USA, 28 September–1 October 2010)

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    The third annual meeting of the AMSE/AIAA Smart Materials, Adaptive Structures and Intelligent Systems Conference (SMASIS) took place in the heart of historic Philadelphia's cultural district, and included a pioneer banquet in the National Constitutional Center. The applications emphasis of the 2010 conference was reflected in keynote talks by Dr Alan Taub, vice president of General Motors global research and development, 'Smart materials in the automotive industry'; Dr Charles R Farrar, engineering institute leader at Los Alamos National Laboratory, 'Future directions for structural health monitoring of civil engineering infrastructure'; and Professor Christopher S Lynch of the University of California Los Angeles, 'Ferroelectric materials and their applications'. The SMASIS conference was divided into six technical symposia each of which included basic research, applied technological design and development, and industrial and governmental integrated system and application demonstrations. The six symposia were: * SYMP 1 Multifunctional Materials; * SYMP 2 Active Materials, Mechanics and Behavior; * SYMP 3 Modeling, Simulation and Control; * SYMP 4 Enabling Technologies and Integrated System Design; * SYMP 5 Structural Health Monitoring/NDE; and * SYMP 6 Bio-inspired Smart Materials and Structures. In addition, the conference introduced a new student and young professional development symposium. Authors of papers in the materials areas (symposia 1, 2 and 6) were invited to write a full journal article on their presentation topic for publication in this special issue of Smart Materials and Structures . This set of papers demonstrates the exceptional quality and originality of the conference presentations. We are appreciative of their efforts in producing this collection of highly relevant articles on smart materials.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90812/1/0964-1726_20_9_090201.pd

    Proof-of-concept investigation of Active Velcro for smart attachment mechanisms

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76230/1/AIAA-2001-1503-863.pd

    Force-Deflection Behavior of a Smart Attachment Mechanism

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77258/1/AIAA-2003-1638-430.pd

    Transformation strain based method for characterization of convective heat transfer from shape memory alloy wires

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    While shape memory alloys (SMAs) have many actuation benefits, their frequencies are commonly restricted by slow cooling times caused by limitations in convective heat transfer. To increase the cooling speed and at the same time reduce excess power consumption from overheating, it is critical to understand the heat transfer from SMA wires. This requires accurate surface temperature measurement under a fixed input power, which is difficult to obtain using traditional methods because of the nature of SMAs (thin wires, large strains, heat activation, ambient environment, etc). This paper introduces a non-invasive technique for calculating the convective coefficient for SMAs by employing the temperature-induced transformation strain of SMAs to estimate the surface temperature. This method was experimentally validated for measurement of the convective coefficient in air where infrared cameras can operate, and then used to indirectly measure the convective coefficient across a range of commonly utilized SMA wire diameters and ambient media where traditional methods are limited. Formulated empirical correlations to the collected data provide a mathematical relationship to calculate the convective coefficient in material models which serve as better estimates of convection, and may be used for optimization of SMA actuators for increased frequency performance while ensuring that power draw is minimized.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85423/1/sms10_3_035005.pd

    Wind tunnel testing of a high authority airspeed insensitive rotor blade flap

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76700/1/AIAA-1999-1503-882.pd

    Force-deflection behavior of piezoelectric C-block actuator arrays

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    C-blocks are unique piezoelectric building blocks which can be combined in series or parallel to generate tailorable performance and exploit the advantages of bender and stack architectures. This paper presents a complete theoretical model that predicts the force-deflection behavior for any generic C-block actuator array configuration. An experimental investigation with five case studies is described that validates the model over a broad range of actuator prototypes and performance. This study characterizes the sensitivity of this class of actuator array with respect to material, geometric, and configuration parameters. The paper concludes with a comparison of the generic C-block architecture to the current state of art on a basis of absolute measures such as maximum force, deflection, and work and normalized measures such as effective stress, strain, and work per actuator volume. From this, it is concluded that C-blocks are a highly efficient, mid-range actuation technology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49008/2/sm9502.pd

    Bench-top characterization of an active rotor blade flap system incorporating C-block actuators

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76706/1/AIAA-1998-2108-892.pd

    Suspension polymerization casting of lead zirconate titanate, part I: Acrylamide hydrogel system

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    Suspension polymerization casting of lead zirconate titanate (PZT) filled acrylamide systems was studied. A high solid loading (51 vol%) PZT slurry with low viscosity (about 280 mPa·s at shear rate 10 s −1 ) was obtained by optimizing the dispersant amount. The polymerization process for the monomer solution and PZT slurry were characterized with the help of the storage modulus measurement. For the monomer solution, the overall activation energy of gelation was calculated as 60–76 kJ/mol, while for the PZT slurry, this energy increased to 91 ± 9 kJ/mol. The drying, burnout and sintering processes were also addressed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44771/1/10853_2004_Article_5141969.pd

    Fabrication and experimental characterization of d31 telescopic piezoelectric actuators

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    A popular and useful piezoelectric actuator is the stack. Unfortunately with this type of actuation architecture the long lengths normally required to obtain necessary displacements can pose packaging and buckling problems. To overcome these limitations, a new architecture for piezoelectric actuators has been developed called telescopic. The basic design consists of concentric shells interconnected by end-caps which alternate in placement between the two axial ends of the shells. This leads to a linear displacement amplification at the cost of force; yet the force remains at the same magnitude as a stack and significantly higher than bender type architectures. This paper describes the fabrication and experimental characterization of three different telescopic prototypes. The actuator prototypes discussed in this paper mark a definitive step forward in fabrication techniques for complex piezoceramic structures. Materials Systems, Inc. has adapted injection molding for the fabrication of net shape piezoceramic actuators. Injection molding provides several advantages over conventional fabrication techniques, including: high production rate, uniform part dimensions, uniform piezoelectric properties, and reduced fabrication and assembly costs. Acrylate polymerization, developed at the University of Michigan, is similar to gelcasting, but uses a nonaqueous slurry which facilitates the production of large, tall, complex components such as the telescopic actuator, and is ideal for the rapid manufacture of unique or small batch structures. To demonstrate these fabrication processes a five tube telescopic actuator was injection molded along with a very tall three tube actuator that was cast using the acrylate polymerization method. As a benchmark, a third actuator was built from off-the-shelf tubes that were joined with aluminum end-caps. Each prototype's free deflection behavior was experimentally characterized and the results of the testing are presented within this paper.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44767/1/10853_2004_Article_382116.pd
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