23 research outputs found

    The Effect of Geometric Scale on the Configuration of a Solar Sail

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77249/1/AIAA-2002-1200-419.pd

    An Experiential Introduction to Aerospace Engineering

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77054/1/AIAA-2007-296-801.pd

    Electrostatic control of a membrane using adaptive feedback linearization

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76357/1/AIAA-1998-4139-522.pd

    Criticality of natural absorbing states

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    We study a recently introduced ladder model which undergoes a transition between an active and an infinitely degenerate absorbing phase. In some cases the critical behaviour of the model is the same as that of the branching annihilating random walk with N≥2N\geq 2 species both with and without hard-core interaction. We show that certain static characteristics of the so-called natural absorbing states develop power law singularities which signal the approach of the critical point. These results are also explained using random walk arguments. In addition to that we show that when dynamics of our model is considered as a minimum finding procedure, it has the best efficiency very close to the critical point.Comment: 6 page

    A reconciliation of dynamic crack velocity and Rayleigh wave speed in isotropic brittle solids

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    Following earlier observations of multiple micro-crack formation accompanying crack propagation under dynamic conditions, the question regarding the discrepancy between the ‘theoretically anticipated’ maximal crack (Rayleigh wave) speed and those observed typically in amorphous, isotropic solids is examined experimentally. It is shown that if the production of these multiple micro-cracks ahead of the main fracture is suppressed by fabricating a material possessing a thin uniform region of vanishing intrinsic (molecular/atomic) material strength, the crack speed is materially increased to the point of approaching the Rayleigh wave speed. Moreover, it is also shown that the presence of small discreet flaws of sufficient spatial density similarly ‘weakens’ the material to produce fracture speeds comparable to the Rayleigh wave speed. One deduces, therefore, that for a single crack front the linearized theory of elastodynamics correctly predicts the dynamic crack propagation behavior of a solid with sufficiently low material strength.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42778/1/10704_2004_Article_BF00032282.pd

    Non-steady, periodic behavior in the dynamic fracture of PMMA

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    A crack moving dynamically through a sheet of Polymethylmethacrylate at high average velocity is found in reality to propagate in a non-steady, periodic, and perhaps discontinuous fashion. The spatial period of the fracture process in the direction of travel, or banding morphology, is of millimeter size and is consistent both in magnitude and discontinuous nature with a crazing mechanism proposed in fatigue settings. The band size in both the dynamic and fatigue environments scales with the applied stress intensity. This commonality has importance in modeling. It suggests that a single mechanism is fundamental in both dynamic and fatigue loading regimes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42774/1/10704_2004_Article_BF00012390.pd

    Flow field and performance of high frequency micromachined synthetic jets

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77283/1/AIAA-2002-974-315.pd

    Resonance Effects of Electrostatically Actuated Acoustic Jets

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77281/1/AIAA-2003-1272-471.pd

    Numerical simulation of micromachined acoustic resonators

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76479/1/AIAA-2000-546-400.pd

    Modeling, Identification, and Feedback Control of Noise in an Acoustic Duct

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57830/1/AcousticDuctTCST1996.pd
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