Passive machine augmented composite for multifunctional properties

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dc.contributor.advisor Creasy , Terry en_US
dc.contributor.committeeMember Boyd , James en_US
dc.creator Kim , Jong Hyun en_US
dc.date.accessioned 2005 -11 -01T15 :46 :58Z
dc.date.accessioned 2014 -02 -19T19 :22 :23Z
dc.date.available 2005 -11 -01T15 :46 :58Z
dc.date.available 2014 -02 -19T19 :22 :23Z
dc.date.created 2005 -08 en_US
dc.date.issued 2005 -11 -01T15 :46 :58Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /2597
dc.description.abstract This dissertation studies by experiment and numerical analysis an advanced composite material (Machine Augmented Composite or MAC ) for enhancement of the passive damping while maintaining its stiffness . This MAC is composed of a pre -buckled wall structure placed within a viscoelastic matrix . The pre -buckled machine can contain viscous fluids for additional energy dissipation . For the experiments , the MAC was fabricated by using rigid and soft polyurethane as a machine and matrix material respectively . Various viscosity fluids (0 .83 ~ 4730 cps ) filled the inner -channel of the machine structure . Dynamic properties such as tan ? ? and the loss modulus (E" ) of the composite were measured and compared with those of a homogeneous matrix sample over a frequency range of 0 .1 to 100 Hz at room temperature through load -controlled cyclic testing . Measured tan ? ? and loss modulus values for the composite were higher than those of the matrix alone in the 1 to 40 Hz range . However the viscous fluid effects on the overall damping properties were small . The performance of a theoretical MAC was explored through numerical analysis . The amount of inner -channel gap closure was calculated for various matrix Poisson ? ?s ratios , for various Young ? ?s modulus ratios between the machine and matrix (Emachine /Ematrix ) , and for the volume fraction of the machines . The most desirable performance of the composite was obtained when the matrix Poisson ? ?s ratio was 0 .49 , and there was interaction between the Emachine /Ematrix and the volume fraction of the machines . Also the proper volume fraction range of the machine was predicted to be between 0 .15 and 0 .2 for the lamina shape MAC . Based upon the analysis , a sandwich structure MAC was fabricated and tested . This composite showed 11 times higher stiffness than the matrix without loosing the matrix damping property . This dissertation shows that the research met these objectives : 1 ) the MAC concept is effective for passive damping of vibrations , 2 ) that material combinations studied here had optimal combinations for best performance , and 3 ) that this is a promising field study for future passive and active materials development . en_US
dc.format.extent 3362041 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject MACHINE en_US
dc.title Passive machine augmented composite for multifunctional properties en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US

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Passive machine augmented composite for multifunctional properties. Available electronically from http : / /hdl .handle .net /1969 .1 /2597 .

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