The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Pedro P. Camanho - One of the best experts on this subject based on the ideXlab platform.
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High strain rate characterisation of unidirectional carbon-epoxy IM7-8552 in Longitudinal Compression
Composites Part A: Applied Science and Manufacturing, 2011Co-Authors: H. Koerber, Pedro P. CamanhoAbstract:Abstract This paper presents an experimental investigation of the strain rate effect on unidirectional carbon–epoxy IM7-8552 loaded in Longitudinal Compression. A dynamic Compression fixture was developed for a split-Hopkinson pressure bar to test flat rectangular specimens. The dynamic experiment was designed by finite element analysis, using an axis-symmetric elastic model of the test setup. Due to the linear specimen stress–strain behaviour, ramp-shaped incident pulses were used, to ensure a constant strain rate and dynamic equilibrium throughout the test. The results from the split-Hopkinson pressure bar experiments at an average strain rate of about 100 s −1 were compared with quasi-static test results using the same test setup. It was found that the Longitudinal compressive modulus is not strain rate sensitive while a significant increase was observed for the Longitudinal compressive strength.
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Characterisation of unidirectional Carbon-Epoxy IM7-8552 in Longitudinal Compression under high strain rates
DYMAT 2009 - 9th International Conferences on the Mechanical and Physical Behaviour of Materials under Dynamic Loading, 2009Co-Authors: H. Körber, Pedro P. CamanhoAbstract:A self-aligning Dynamic Compression Fixture, which can be used with a conventional Split-Hopkinson Pressure Bar, was developed to characterise the advanced composite carbon/epoxy material system IM7-8552 in Longitudinal Compression under high strain rates. The development of the dynamic experiment was supported by Finite Element Analysis, using a simple axi-symmetric elastic model of the dynamic test setup. Due to the quasi-brittle material behaviour in the long- itudinal direction, a triangular shaped pulse is used, which creates a near constant strain rate while also ensuring dynamic equilibrium throughout the test. Tungsten-carbide inserts were used at the bar-specimen interfaces to prevent indentation of the bar ends due to the high strength specimen used. The results from the Split-Hopkinson Pressure Bar experiment, at a strain rate of approx. 100 s x1 , were compared with results from quasi-static tests using the same test setup. Analysing the first test results it is likely that the Longitudinal compressive chord modulus of elasticity is not strain rate sensitive while an increase was found for the Longitudinal compressive strength. The application of polymer-based composite materials in crashworthy structures, and the related need to simulate the mechanical response of composites under high strain rates, requires a clean identification of the relevant material properties. Different authors have performed high strain rate Longitudinal Compression tests for different unidirectional carbon/epoxy material systems. Hsiao and Daniel (1) used a falling weight impact tower and thick composite specimens with bonded steel end caps. They found a 78% increase of Longitudinal compressive strength at higher strain rates but no rate effects for the compressive Longitudinal modulus of elasticity. Hosur et al (2) tested 6 mm cubic carbon/epoxy Longitudinal Compression samples using a Recovery Split-Hopkinson Pressure Bar (SHPB) and found a two- fold increase for stiffness while strength increased by only 17% under dynamic loading. Both authors observed splitting and end crushing as failure modes. In the presented work a dynamic Longitudinal Compression experiment was designed to test a relatively thin and long specimen with nominal dimensions of 1.5 mmr 7m mr 23 mm in a classic SHPB setup. Great care was taken in selecting an appropriate incident pulse shape to ensure a near constant strain rate and dynamic equilibrium throughout the test.
H. Koerber - One of the best experts on this subject based on the ideXlab platform.
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Characterization of unidirectional carbon fiber reinforced polyamide-6 thermoplastic composite under Longitudinal Compression loading at high strain rate
EPJ Web of Conferences, 2015Co-Authors: Marina Ploeckl, Peter Kuhn, H. KoerberAbstract:In the presented work, an experimental investigation has been performed to characterize the strain rate dependency of unidirectional carbon fiber reinforced polyamide-6 composite for Longitudinal Compression loading. An end-loaded Compression specimen geometry, suitable for contactless optical strain measurement via digital image correlation and dynamic loading in a split-Hopkinson pressure bar, was developed. For the dynamic experiments at a constant strain rate of 100 s −1 a modified version of the Dynamic Compression Fixture, developed by Koerber and Camanho [Koerber and Camanho, Composites Part A, 42, 462–470, 2011] was used. The results were compared with quasi-static test results at a strain rate of 3 · 10 −4 s −1 using the same specimen geometry. It was found that the Longitudinal compressive strength increased by 61% compared to the strength value obtained from the quasi-static tests.
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High strain rate characterisation of unidirectional carbon-epoxy IM7-8552 in Longitudinal Compression
Composites Part A: Applied Science and Manufacturing, 2011Co-Authors: H. Koerber, Pedro P. CamanhoAbstract:Abstract This paper presents an experimental investigation of the strain rate effect on unidirectional carbon–epoxy IM7-8552 loaded in Longitudinal Compression. A dynamic Compression fixture was developed for a split-Hopkinson pressure bar to test flat rectangular specimens. The dynamic experiment was designed by finite element analysis, using an axis-symmetric elastic model of the test setup. Due to the linear specimen stress–strain behaviour, ramp-shaped incident pulses were used, to ensure a constant strain rate and dynamic equilibrium throughout the test. The results from the split-Hopkinson pressure bar experiments at an average strain rate of about 100 s −1 were compared with quasi-static test results using the same test setup. It was found that the Longitudinal compressive modulus is not strain rate sensitive while a significant increase was observed for the Longitudinal compressive strength.
Kemal Baysal - One of the best experts on this subject based on the ideXlab platform.
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Letter to the Editor An unexpected complication during stent implantation for coarctation of the aorta: Longitudinal stent Compression
2009Co-Authors: Metin Sungur, Alpay Celiker, Tevfik Karagöz, Kemal BaysalAbstract:We report a 17-year-old adolescent with diagnosis of the coarctation of aorta (CoA) underwent stent implantation in which complicated with non expansion and Longitudinal Compression of the stent. © 2008 Elsevier Ireland Ltd. All rights reserved.
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An unexpected complication during stent implantation for coarctation of the aorta: Longitudinal stent Compression
International journal of cardiology, 2008Co-Authors: Metin Sungur, Alpay Celiker, Tevfik Karagöz, Kemal BaysalAbstract:We report a 17-year-old adolescent with diagnosis of the coarctation of aorta (CoA) underwent stent implantation in which complicated with non expansion and Longitudinal Compression of the stent.
Regis Rieu - One of the best experts on this subject based on the ideXlab platform.
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Longitudinal Compression behaviour of coronary stents a bench top comparative study
Eurointervention, 2014Co-Authors: Paul Barragan, Vincent Garitey, Karim Mouneimne, Regis RieuAbstract:AIMS The aim of this study was to characterise the coronary stent Longitudinal resistance of new coronary stents under worst case clinical crossing simulated configurations. METHODS AND RESULTS Six coronary balloon-expandable stents were evaluated using two different tests. The first was a direct parallel plates Longitudinal crush resistance test: it was conducted on stents deployed to 3 mm diameter, and three samples of each model were used. The second was performed by tracking over the wire and deploying the stents in two types of coronary model: good and malapposition models. Two samples of each model were used for this test. After deployment, a PTCA balloon was advanced over the wire. For each stent, the force required for balloon tracking and the stent shortening were recorded. In the first crush test, three out of six stent models demonstrated higher Longitudinal crush rates compared to the Resolute Integrity (Medtronic, Minneapolis, MN, USA): PROMUS Element™ (Boston Scientific, Natick, MA, USA) p<0.0001, Coroflex® Blue (B. Braun, Melsungen, Germany) p<0.0001, and Orsiro (Biotronik, Berlin, Germany) p=0.038. In the simulation test, there were no statistical differences when comparing all good and malapposition groups. CONCLUSIONS Lower resistance to mechanical Longitudinal Compression of some stents did not correlate to significantly higher crush rates in simulated clinical conditions. Nevertheless, it would be useful for cardiologists to be aware of the actual mechanical characteristics of new stents to take them into account and thus minimise Longitudinal Compression during difficult stent implantations.
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TCT-536 Biomechanical assessment of the Longitudinal Compression behavior of drug eluting coronary stents: an in vitro comparative study
Journal of the American College of Cardiology, 2012Co-Authors: Regis Rieu, Paul Barragan, Vincent Garitey, Karim MouneimneAbstract:Significant Longitudinal Compression has been clinically observed in cases where drug-eluting coronary stents were crossed by other interventional devices. Our objective was to characterize stent Longitudinal resistance under simulated clinical worst case crossing scenarios in good apposition and
Metin Sungur - One of the best experts on this subject based on the ideXlab platform.
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Letter to the Editor An unexpected complication during stent implantation for coarctation of the aorta: Longitudinal stent Compression
2009Co-Authors: Metin Sungur, Alpay Celiker, Tevfik Karagöz, Kemal BaysalAbstract:We report a 17-year-old adolescent with diagnosis of the coarctation of aorta (CoA) underwent stent implantation in which complicated with non expansion and Longitudinal Compression of the stent. © 2008 Elsevier Ireland Ltd. All rights reserved.
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An unexpected complication during stent implantation for coarctation of the aorta: Longitudinal stent Compression
International journal of cardiology, 2008Co-Authors: Metin Sungur, Alpay Celiker, Tevfik Karagöz, Kemal BaysalAbstract:We report a 17-year-old adolescent with diagnosis of the coarctation of aorta (CoA) underwent stent implantation in which complicated with non expansion and Longitudinal Compression of the stent.
