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ion Carbon/Carbon Composite Project

Igor I. Tsukrov, University of New Hampshire, DMR 0806906Outcome: A significant multidisciplinary collaborative effort between the University of New Hampshire (UNH) and Karlsruhe Institute of Technology (KIT) has been carried out in the past 4 years to study carbon/carbon composites.

Impact: A comprehensive model to predict thermo-mechanical properties of carbon/carbon composite on all length scales (nano, micro, meso and macro) has been developed and published in 12 international journal papers, 16 peer-reviewed national and international conference proceedings, and 40 international conference presentations.

Explanation: Chemical vapor infiltrated carbon/carbon composites have a complex hierarchical microstructure that has to be considered on submicron (nanotextured pyrolytic carbon, PyC), micro (transversely isotropic infiltrated fiber bundles) and meso (porous fiber-PyC system) length scales. The multiscale model developed within this project for carbon/carbon composites can be utilized for a wide range of fiber-reinforced composite materials.

Complex hierarchical microstructure of a specimen of chemical vapor infiltrated

carbon/carbon composite

German (KIT) and American (UNH) C/C Project teams during a project meeting in UNH

www.unh.edu/cc-composites

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ion Statistical Analysis of Microtomography Data

Igor I. Tsukrov, University of New Hampshire, DMR 0806906Many structural materials contain pores of various shapes and sizes. Some of these materials’ pores perform a specific function (thermal isolation, weight reduction, etc), and some are the by-product of the manufacturing process. In any case, pores of irregular shapes present a modeling challenge for engineers and scientists.

In the past year, a procedure to identify, analyze and process the irregular pores obtained from microtomography data has been developed*. The procedure was illustrated for a specimen of carbon/carbon composite. As a result of the processing, a 4-factor statistical model was proposed to predict contribution of irregular pores to the effective elastic properties of an isotropic material based on their geometric parameters. A good agreement between the model and the measured response (based on FEA simulations of the individual pore shapes) was observed: the average R2 value for 5 parameters characterizing contribution to elastic properties was 0.87.

Empirical spherical probability density function of pore orientations in a

specimen of carbon/carbon composite

Actual vs Predicted plot for the model predicting contribution of irregular pores to the effective bulk modulus

based on their geometric parameterswww.unh.edu/cc-composites

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ion Pyrolytic Carbon in Total Artificial Heart

Igor I. Tsukrov, University of New Hampshire, DMR 0806906Syncardia Total Artificial Heart (TAH-t) is used as a bridge to transplant for patients with biventricular failure. Due to vital importance of the device’s uninterrupted service for months and years after implantation, all the components of TAH-t including heart valves are subject to very high reliability requirements.

Heart valve components in TAH-t are coated with a thin layer of pyrolytic carbon for better surface durability and biocompatibility. Syncardia Systems Inc., approached the NSF-MWN Carbon/Carbon Project team with request for assistance in analyzing the pyrolytic carbon coating performance .

Methods developed within the NSF-MWN project were utilized by the UNH graduate student Borys Drach to analyze the performance and predict fatigue life of mechanical heart valves in Syncardia Total Artificial Heart during his summer internship at Syncardia Systems, Inc. (Tucson, AZ).

Director of Engineering with SynCardia Systems, Inc. Curtis Brown (left) and UNH graduate student

Borys Drach holding two ventricles of the SynCardia Total Artificial Heart.

www.syncardia.comRight ventricle of Syncardia Total Artificial Heart with two Medtronic-Hall heart valves (discs are

coated with pyrolytic carbon)