11:20
Biomedical and Natural Materials
Chair: Amir Zadpoor
11:20
20 mins
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MEASURING ORTHOTROPIC STIFFNESS COMPONENTS OF WOOD BY PLATE BENDING TESTS
José Xavier, Herani Lopes, Fabrice Pierron, José Morais, Mário Vaz
Abstract: This work presents a study on the characterisation of orthotropic elastic properties of Pinus pinaster Ait. from heterogeneous plate bending tests. The proposed approach couples full-field slope measurements provided by the deflectometry technique with the virtual fields method, assuming Kirchhoff-Love classical plate theory. Experimentally, a procedure was implemented to coat the surface of clear wood to guarantee specular reflection. The curvature fields were reconstructed from phase evaluation, phase unwrapping and slope polynomial approximation and differentiation procedures. The curvature fields, together with the applied punctual load and the plate dimensions were then input in the virtual fields method for simultaneous material parameter identification. The mean values of the engineering constants obtained from the proposed approach were found in good agreement with regard to reference ones reported in the literature for the same species and determined independently from classical tensile and shear mechanical tests.
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11:40
20 mins
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HEART RATE MONITORING IN PRESENCE OF INDUCED MOTION ARTIFACTS
Mahsa Nemati, Nandini Bhattacharya, Paul Urbach
Abstract: Continuous health monitoring has become a major theme of our aging society. Portable devices play an important role here. Many optical portable devices are susceptible to motion induced artifacts. We have performed an experimental study for detection of fluid pulsation based on multi-exposure speckle images, in presence of motion induced artifacts. Induced motion of a wide range of frequencies and amplitudes were generated to resemble sensor motion with respect to skin. The data was analyzed using speckle contrast and correlation. We concluded that both techniques have their own advantages, depending on the measurement configuration. A study of angles between illumination and detection revealed that larger angles yields better signal. Shorter exposure time was more successful in extracting the signal. We
also performed in-vivo measurements that agree with the in-vitro case. We also show that a minimum collection of two pixels from the speckle image is sufficient to extract relevant results.
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12:00
20 mins
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PHOTOMECHANICAL STRESS ANALYSIS OF CELLULOSIC-MANURE COMPOSITES
Yoon Ro, John Hunt, Robert Rowlands
Abstract: Being able to stress analyze green materials such as cellulosic-manure composites addresses several societal issues. These include providing engineering members fabricated from materials which can be particularly suitable for developing nations, relieving a troubling by-product of agricultural regions and reducing the demands on our landfills. However most engineering applications of these materials necessitate knowledge of their structural integrity. This implies ability to evaluate stresses in such materials. Motivated by the above, this paper describes the ability to photomechanically stress analyze engineering members produced from such green materials.
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