Mechanical characterization of unfired earth via numerical assessment of the experimental data

Experimental data and a suitable material model for human aortas with smooth muscle activation are not available in the literature despite the need for developing advanced grafts; the present study closes this gap. Mechanical characterization of human descending thoracic aortas was performed with and without vascular smooth muscle (VSM) activation. Specimens were taken from 13 heart-beating donors. The aortic segments were cooled in Belzer UW solution during transport and tested within a few hours after explantation. VSM activation was achieved through the use of potassium depolarization and noradrenaline as vasoactive agents. In addition to isometric activation experiments, the quasistatic passive and active stress–strain curves were obtained for circumferential and longitudinal strips of the aortic material. This characterization made it possible to create an original mechanical model of the active aortic material that accurately fits the experimental data. The dynamic mechanical characterization was executed using cyclic strain at different frequencies of physiological interest. An initial prestretch, which corresponded to the physiological conditions, was applied before cyclic loading. Dynamic tests made it possible to identify the differences in the viscoelastic behavior of the passive and active tissue. This work illustrates the importance of VSM activation for the static and dynamic mechanical response of human aortas. Most importantly, this study provides material data and a material model for the development of a future generation of active aortic grafts that mimic natural behavior and help regulate blood pressure.

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Mechanical Characterization of Embedded Serpentine Conductors in Wearable Electronics

Journal of Electronic Packaging ◽

10.1115/1.4046163 ◽

2020 ◽

Vol 142 (2) ◽

Cited By ~ 4

Author(s):

Chong Ye ◽

Charles I. Ume ◽

Suresh K. Sitaraman

Keyword(s):

Experimental Data ◽

Digital Image Correlation ◽

Strain Distribution ◽

Mechanical Characterization ◽

Neutral Line ◽

Image Correlation ◽

Wearable Electronics ◽

Two Dimensional ◽

Supporting Materials

Abstract Wearable electronics undergo stretching, flexing, bending, and twisting during the process of being put on and while being worn. In addition, wearable textile electronics also need to survive under cyclic washing. During such processes, it is necessary to ensure that the electronics as well as the conductors and various other supporting materials remain reliable. In this work, mechanical characterization of various materials in a commercially available smart shirt is presented. The serpentine conductor used in the smart shirt has been carefully examined to understand the strain distribution at various locations under stretching. Both analytical formulations and numerical simulations have been carried out to determine the strain distribution in the serpentine structure, and the results from the simulations have been compared against experimental data obtained through two-dimensional digital image correlation (2D DIC). Various design configurations of the semicircular serpentine structure have been studied in this work, and a relationship between width and the neutral line radius of the semicircular serpentine structure has been obtained to reduce maximum strains in the serpentine structure under stretching.

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Mechanical Behavior of Polymer Nanocomposites: a discrete simulation approach

MRS Proceedings ◽

10.1557/proc-740-i6.1 ◽

2002 ◽

Vol 740 ◽

Cited By ~ 1

Author(s):

E. Chabert ◽

C. Gauthier ◽

R. Dendievel ◽

L. Chazeau ◽

J.-Y. Cavaillé

Keyword(s):

Experimental Data ◽

Polymer Nanocomposites ◽

Mechanical Characterization ◽

Spherical Particles ◽

Simulation Approach ◽

General Sense ◽

Discrete Simulation ◽

Reinforcing Particles ◽

Good Agreement

ABSTRACTThis work reports the dynamic mechanical characterization of nanocomposites based on a poly(butyl acrylate) matrix filled with spherical particles of either polystyrene or silica both of diameter around 100 nm. A discrete numerical simulation, taking into account the microstructure and the nature of contact between reinforcing particles has been developed. This simulation enables to quantify the effect of interactions between filler particles on the elastic modulus, and in a more general sense, to clarify the concept of mechanical percolation. It gives results in very good agreement with experimental data.

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Mechanical characterization of Trebisacce stone: preliminary results

Rendiconti online della Società Geologica Italiana ◽

10.3301/rol.2016.14 ◽

2016 ◽

Vol 38 ◽

pp. 47-50

Author(s):

Giulia Forestieri ◽

Maurizio Ponte

Keyword(s):

Mechanical Characterization ◽

Preliminary Results

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Massively Parallel Mechanical Characterization of Nanowires

10.26226/morressier.5f5f8e69aa777f8ba5bd5f86 ◽

2020 ◽

Author(s):

Rodrigo Bernal

Keyword(s):

Mechanical Characterization ◽

Massively Parallel

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Spectro-mechanical Characterization of Aromaticity and Maturity of Kerogens in Oil Shale at 6 nm Spatial Resolution

10.26434/chemrxiv.7336160 ◽

2018 ◽

Author(s):

Devon Jakob ◽

Le Wang ◽

Haomin Wang ◽

Xiaoji Xu

Keyword(s):

Spatial Resolution ◽

Oil Shale ◽

Infrared Imaging ◽

Mechanical Characterization ◽

Optical Diffraction ◽

Chemical Compositions ◽

Valuable Insight ◽

Eagle Ford Shale

<p>In situ measurements of the chemical compositions and mechanical properties of kerogen help understand the formation, transformation, and utilization of organic matter in the oil shale at the nanoscale. However, the optical diffraction limit prevents attainment of nanoscale resolution using conventional spectroscopy and microscopy. Here, we utilize peak force infrared (PFIR) microscopy for multimodal characterization of kerogen in oil shale. The PFIR provides correlative infrared imaging, mechanical mapping, and broadband infrared spectroscopy capability with 6 nm spatial resolution. We observed nanoscale heterogeneity in the chemical composition, aromaticity, and maturity of the kerogens from oil shales from Eagle Ford shale play in Texas. The kerogen aromaticity positively correlates with the local mechanical moduli of the surrounding inorganic matrix, manifesting the Le Chatelier’s principle. In situ spectro-mechanical characterization of oil shale will yield valuable insight for geochemical and geomechanical modeling on the origin and transformation of kerogen in the oil shale.</p>

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