Publications de Alexandre Jean Pachoud

Advanced models for stress evaluation and safety assessment in steel-lined pressure tunnels

Anton Schleiss, Pedro Filipe De Almeida Manso, Alexandre Jean Pachoud

An accurate estimation of the stress in a steel liner is required for the design of steel-lined pressure shafts, both with regard to safety assessment of ageing steel-lined waterways of hydropower plants built in the 20th century, and for new projects whic ...

2018

Influence of geometrical imperfections and flaws at welds of steel liners on fatigue behavior of pressure tunnels and shafts in anisotropic rock

Alexandre Jean Pachoud

The recent development of high-strength (HSS) weldable steels has enlarged the range of design alternatives for the optimization of high-head steel-lined pressure tunnels and shafts (SLPT&S) in the hydropower industry. With the liberalization of the Europe ...

EPFL2017

Stress intensity factors for axial semi-elliptical surface cracks and embedded elliptical cracks at longitudinal butt welded joints of steel-lined pressure tunnels and shafts considering weld shape

Anton Schleiss, Pedro Filipe De Almeida Manso, Alexandre Jean Pachoud

When for steel liners of pressure tunnels and shafts high-strength steels are used, welded joints are subject to the risk of hydrogen induced cold-cracking in the base material. Longitudinal butt welded joints are critical regions as they are loaded transv ...

Elsevier2017

New parametric equations to estimate notch stress concentration factors at butt welded joints modeling the weld profile with splines

Anton Schleiss, Pedro Filipe De Almeida Manso, Alexandre Jean Pachoud

For fatigue life estimation as well as for fatigue testing analysis of welded structures by local stresses approaches, the stress concentration factor (SCF) at the weld must be known. Full penetration butt welded joints are extensively used in steel struct ...

Elsevier2016

Stresses and displacements in steel-lined pressure tunnels and shafts in anisotropic rock under quasi-static internal water pressure

Anton Schleiss, Alexandre Jean Pachoud

Steel-lined pressure tunnels and shafts are constructed to convey water from reservoirs to hydroelectric power plants. They are multilayer structures made of a steel liner, a cracked backfill concrete layer, a cracked or loosened near-field rock zone and a ...

Springer Wien2016

Signal analysis of an actively generated cavitation bubble in pressurized pipes for detection of wall stiffness drops

Giovanni De Cesare, Anton Schleiss, Mohamed Farhat, Fadi Hachem, Alexandre Jean Pachoud

Due to the increasing production of volatile new renewable energies as solar and wind, storage hydropower plants have to operate under harsh operation conditions in order to stabilize the electricity grid. As a result, highly transient water pressures occu ...

Elsevier2016

Parametric Study of Steel-Lined pressure Shafts in Anisotropic Rock

Anton Schleiss, Alexandre Jean Pachoud

Steel-lined pressure tunnels and shafts are used to convey water from the reservoir to the turbines in high-head hydroelectric power plants. An axisymmetrical multilayer model is of-ten considered by engineers for the design of the steel liner. Stresses an ...

2015

Steel-lined pressure tunnels and shafts in anisotropic rock

Anton Schleiss, Alexandre Jean Pachoud

Faculty of Engineering of University of Porto2014

Flow field UVP measurements of a Y-shape outlet structure

Giovanni De Cesare, Alexandre Jean Pachoud

Y-shape outlet structures are used to release the turbine water into a reservoir. Classical design oftenuses a Y-shape over a certain length and with a specific opening angle. Depending on the geometry,especially in turbine mode, significant undesired flow ...

2014