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John Botsis

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Publications associées (116)

Fatigue strengthening of damaged metallic beams using prestressed unbonded and bonded CFRP plates

Andrin Herwig, John Botsis, Matteo Galli, Elyas Ghafoori, Masoud Motavalli

Bonded fiber reinforced polymers (FRPs) reinforcement systems have traditionally been found to be an efficient method for improving the lifespan of fatigued metallic structures and have attracted much research attention. Nevertheless, the performance of a ...

Elsevier2012

Characterization of impact damage in fibre reinforced composite plates using embedded FBG sensors

Joël Cugnoni, Thomas Gmür, John Botsis, Jeannot Frieden

EPFL2011

Hydro-mechanical coupling in the periodontal ligament: A porohyperelastic finite element model

Joël Cugnoni, John Botsis, Marzio Bergomi, Matteo Galli

Harmonic tension–compression tests at 0.1, 0.5 and 1 Hz on hydrated bovine periodontal ligament (PDL) were numerically simulated. The process was modeled by finite elements (FE) within the framework of poromechanics, with the objective of isolating the con ...

Elsevier2011

On the Mutual Effect of Viscoplasticity and Interfacial Damage Progression in Interfacial Fracture of Lead-Free Solder Joints

Joël Cugnoni, John Botsis, Milad Maleki

The main goal of this paper is to shed light on the effect of strain rate and viscoplastic deformation of bulk solder on the interfacial failure of lead-free solder joints. For this purpose, interfacial damage evolution and mode I fracture behavior of the ...

Springer US2011

Low-velocity impact damage identification in CFRP plates using inverse numerical-experimental optimization

Joël Cugnoni, Thomas Gmür, John Botsis, Jeannot Frieden

FEUP2011

Crack - fiber sensor interaction and characterization of the bridging tractions in mode I delamination

Joël Cugnoni, John Botsis, Samuel Stutz

Fiber bridging is regularly encountered in model delamination tests of unidirectional fiber reinforced composites. However, characterization of the bridging tractions is rather difficult. One way to indirectly evaluate the bridging traction distribution is ...

2011

Vibration-based characterization of impact induced delamination in composite plates using embedded FBG sensors and numerical modelling

Joël Cugnoni, John Botsis, Jeannot Frieden

Dynamic strain signals from embedded fiber Bragg grating sensors are used for experimental modal analysis in carbon fiber reinforced polymer plates. Throughout a series of impact tests, the change of eigen-frequencies due to damage is evaluated for differe ...

2011

Studies of mode I delamination in monotonic and fatigue loading using FBG wavelength multiplexing and numerical analysis

Joël Cugnoni, John Botsis, Samuel Stutz

Bridging by intact fibers in composite materials is one of the most important toughening mechanisms. However, a direct experimental assessment of its contribution is not easy to achieve. In this work a semi-experimental method is proposed to quantify its c ...

2011

The role of the fluid phase in the viscous response of bovine periodontal ligament

Joël Cugnoni, John Botsis, Marzio Bergomi

The mechanical response of the periodontal ligament (PDL) is complex. This tissue responds as a hyperelastic solid when pulled in tension while demonstrating a viscous behavior under compression. This intricacy is reflected in the tissue's morphology, whic ...

2010

High-speed internal strain measurements in composite structures under dynamic load using embedded FBG sensors

Joël Cugnoni, Thomas Gmür, John Botsis, Jeannot Frieden, Dragan Coric

Internal strain measurements in cross-ply carbon-epoxy composite plates under dynamic loads are carried out using embedded FBG sensors. The principle of the FBG interrogation is based on intensity demodulation achieved via a Fabry-Perot filter. To account ...

2010

Evaluation of residual strains in epoxy with different nano/micro-fillers using embedded fiber Bragg grating sensor

John Botsis, Marco Lai, Klaus Friedrich

The Influence of SiO2 nanoparticles and rubber micro-fillers on the mechanical and thermal responses of an epoxy based composite is investigated using classical quantitative thermo-mechanical testing (tensile tests DMTA TMA) microstructural analysis (Micro ...

2010

Damage assessment in CFRP plates based on dynamic measurements with FBG sensors

Joël Cugnoni, Thomas Gmür, John Botsis, Jeannot Frieden

Civil-Comp Press2010

Distributed strain measurements using fiber Bragg gratings in small-diameter optical fiber and low-coherence reflectometry

Hans Georg Limberger, John Botsis, Dragan Coric, Marco Lai, Aiping Luo

Optical low coherence reflectometry and fiber Bragg gratings written in small diameter (50 micrometer) optical fibers were used for measurements of non-homogenous internal strain fields inside an epoxy specimen with sub-grating length resolution. The resul ...

Optical Society of America2010

Load Response of Periodontal Ligament: Assessment of Fluid Flow, Compressibility, and Effect of Pore Pressure

John Botsis, Marzio Bergomi, Aïssa Mellal

The periodontal ligament (PDL) functions both in tension and in compression. The presence of an extensive vascular network inside the tissue suggests a significant contribution of the fluid phase to the mechanical response. This study examined the load res ...

2010

Three-dimensional morphometry of strained bovine periodontal ligament using synchrotron radiation-based tomography

Joël Cugnoni, John Botsis, Marzio Bergomi, Philipp Schneider, Marco Stampanoni

The periodontal ligament (PDL) is a highly vascularized soft connective tissue. Previous studies suggest that the viscous component of the mechanical response may be explained by the deformation-induced collapse and expansion of internal voids (i.e. chiefl ...

2010

Mechanical response of periodontal ligament: Effects of specimen geometry, preconditioning cycles and time lapse

John Botsis, Marzio Bergomi

This study was conducted as part of research line addressing the mechanical response of periodontal ligament (PDL) to tensile-compressive sinusoidal loading The aim of the present project was to determine the effect of three potential sources of variabilit ...

2009

Internal strain measurements in CFRP plates subjected to impact load using FBG sensors

Joël Cugnoni, Thomas Gmür, John Botsis, Jeannot Frieden, Dragan Coric

The British Composites Society2009

An axisymmetric stress analysis in a single fibre composite of finite length under a thermal expansion mismatch

John Botsis, Laurent Humbert, Fabiano Colpo

In this paper, an exact solution is derived for the characterization of thermal stresses in a single-fibre composite of finite length. All the required boundary and interfacial conditions of the thermo-elastic problem are thus satisfied exactly. The propos ...

2009

Characterization of the Residual Stresses and Strength of Ceramic-Metal Braze Joints

John Botsis, Matteo Galli

Residual stress relief in ceramic-metal joints produced by active brazing depends primarily on the plastic response of the filler metal. A procedure for the production and mechanical characterization of bulk active filler alloy specimens is developed. In p ...

2009

Stress and failure analysis of crimped metal-composite joints used in electrical insulators subjected to bending

Thomas Gmür, John Botsis, Alain Michel Prenleloup

Experimental and numerical investigations are carried out on metal/fibregiass-reinforced-plastic joints integrated in electrical insulators subject to bending. Numerical stress and strain distributions through the bond are calculated with a solid 3D finite ...

2009

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