The Experts below are selected from a list of 7500 Experts worldwide ranked by ideXlab platform
J Vazquez - One of the best experts on this subject based on the ideXlab platform.
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closed form solutions for tilted three part piecewise quadratic half plane contacts
International Journal of Mechanical Sciences, 2019Co-Authors: H Andresen, David A Hills, J VazquezAbstract:Abstract A general half-plane contact problem in which the geometry is specified in a piecewise-quadratic sense over three segments is solved in closed form. This includes the effects of a moment applied sufficient to introduce separation of one segment and the application of a Shearing Force sufficient or insufficient to cause sliding. Extending existing solutions to asymmetrical problems is necessary in order to broaden our understanding of the behaviour of dovetail roots of gas turbine fan blades. In previous studies symmetrical contacts have often been used to represent a dovetail flank contact. In the asymmetrical case, the contact pressure may be considerably higher at one of the contact edges compared to the corresponding symmetrical case. Exploiting the generality provided with the solution presented in this study, several simpler indenter problems are investigated making use of an algebraic manipulator. The Mathematica code is made available for download.
Gino Dini - One of the best experts on this subject based on the ideXlab platform.
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laser beam welding of dissimilar stainless steels in a fillet joint configuration
Journal of Materials Processing Technology, 2012Co-Authors: M.m.a. Khan, Luca Romoli, M. Fiaschi, Gino Dini, F. SarriAbstract:Abstract This paper investigates laser beam welding of dissimilar AISI 304L and AISI 430 stainless steels. Experimental studies were focused on effects of laser power, welding speed, defocus distance, beam incident angle, and line energy on weld bead geometry and Shearing Force. Metallurgical analysis was conducted on a selected weld only to show various microstructures typically formed at different zones and consequent change in microhardness. Laser power and welding speed were the most significant factors affecting weld geometry and Shearing Force. All the bead characteristics but radial penetration depth decreased with increased beam incident angle. The focused beam allowed selecting lower laser power and faster welding speed to obtain the same weld geometry. Weld shape factor increased rapidly due to keyhole formation for line energy input ranging from 15 kJ/m to 17 kJ/m. Fusion zone microstructures contained a variety of complex austenite–ferrite structures. Local microhardness of fusion zone was greater than that of both base metals.
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experimental design approach to the process parameter optimization for laser welding of martensitic stainless steels in a constrained overlap configuration
Optics and Laser Technology, 2011Co-Authors: M.m.a. Khan, Luca Romoli, M. Fiaschi, Gino Dini, F. SarriAbstract:Abstract This paper presents an experimental design approach to process parameter optimization for the laser welding of martensitic AISI 416 and AISI 440FSe stainless steels in a constrained overlap configuration in which outer shell was 0.55 mm thick. To determine the optimal laser-welding parameters, a set of mathematical models were developed relating welding parameters to each of the weld characteristics. These were validated both statistically and experimentally. The quality criteria set for the weld to determine optimal parameters were the minimization of weld width and the maximization of weld penetration depth, resistance length and Shearing Force. Laser power and welding speed in the range 855–930 W and 4.50–4.65 m/min, respectively, with a fiber diameter of 300 μm were identified as the optimal set of process parameters. However, the laser power and welding speed can be reduced to 800–840 W and increased to 4.75–5.37 m/min, respectively, to obtain stronger and better welds.
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Experimental investigation on laser beam welding of martensitic stainless steels in a constrained overlap joint configuration
Journal of Materials Processing Technology, 2010Co-Authors: M.m.a. Khan, Luca Romoli, M. Fiaschi, F. Sarri, Gino DiniAbstract:Abstract This paper presents experimental investigation of laser beam welding of martensitic stainless steels in a constrained overlap configuration. Experimental studies were focused on the effects of laser power, welding speed and fiber diameter on bead geometry and mechanical properties of the weld. Metallurgical study of a selected welded joint was done only to show various microstructures typically formed at different zones. Laser power and welding speed were found the most significant factors affecting the weld geometry and Shearing Force. The contour plots showing constant response lines indicated the evidence of two-factor interaction effects of laser power-welding speed, welding speed-fiber diameter, and fiber diameter-laser power on all the responses except the weld width. Moreover, energy density plots illustrated its linear relationship with penetration depth and limited nonlinear effects on others. Additionally, metallurgical analysis of fusion zone showed dendritic structures consisted of martensitic with eutectic ferrite along solidification grain and subgrain boundaries.
Nathan T Wright - One of the best experts on this subject based on the ideXlab platform.
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mechanical dissociation of the m band titin obscurin complex is directionally dependent
FEBS Letters, 2015Co-Authors: Tracy A Caldwell, Isaiah Sumner, Nathan T WrightAbstract:Titin and obscurin, two giant muscle proteins, bind to each other in an antiparallel Ig–Ig fashion at the M-band. This interaction must be able to withstand the mechanical strain that the M-band typically experiences and remain intact. The mechanical Force on these domains is likely exerted along one of two axes: a longitudinal axis, resulting in a ‘Shearing’ Force, or a lateral axis, resulting in a ‘peeling’ Force. Here we present molecular dynamics data suggesting that these Forces result in distinct unraveling pathways of the titin/obscurin complex and that peeling the domains apart requires less work and Force.
H Andresen - One of the best experts on this subject based on the ideXlab platform.
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closed form solutions for tilted three part piecewise quadratic half plane contacts
International Journal of Mechanical Sciences, 2019Co-Authors: H Andresen, David A Hills, J VazquezAbstract:Abstract A general half-plane contact problem in which the geometry is specified in a piecewise-quadratic sense over three segments is solved in closed form. This includes the effects of a moment applied sufficient to introduce separation of one segment and the application of a Shearing Force sufficient or insufficient to cause sliding. Extending existing solutions to asymmetrical problems is necessary in order to broaden our understanding of the behaviour of dovetail roots of gas turbine fan blades. In previous studies symmetrical contacts have often been used to represent a dovetail flank contact. In the asymmetrical case, the contact pressure may be considerably higher at one of the contact edges compared to the corresponding symmetrical case. Exploiting the generality provided with the solution presented in this study, several simpler indenter problems are investigated making use of an algebraic manipulator. The Mathematica code is made available for download.
F. Sarri - One of the best experts on this subject based on the ideXlab platform.
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laser beam welding of dissimilar stainless steels in a fillet joint configuration
Journal of Materials Processing Technology, 2012Co-Authors: M.m.a. Khan, Luca Romoli, M. Fiaschi, Gino Dini, F. SarriAbstract:Abstract This paper investigates laser beam welding of dissimilar AISI 304L and AISI 430 stainless steels. Experimental studies were focused on effects of laser power, welding speed, defocus distance, beam incident angle, and line energy on weld bead geometry and Shearing Force. Metallurgical analysis was conducted on a selected weld only to show various microstructures typically formed at different zones and consequent change in microhardness. Laser power and welding speed were the most significant factors affecting weld geometry and Shearing Force. All the bead characteristics but radial penetration depth decreased with increased beam incident angle. The focused beam allowed selecting lower laser power and faster welding speed to obtain the same weld geometry. Weld shape factor increased rapidly due to keyhole formation for line energy input ranging from 15 kJ/m to 17 kJ/m. Fusion zone microstructures contained a variety of complex austenite–ferrite structures. Local microhardness of fusion zone was greater than that of both base metals.
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experimental design approach to the process parameter optimization for laser welding of martensitic stainless steels in a constrained overlap configuration
Optics and Laser Technology, 2011Co-Authors: M.m.a. Khan, Luca Romoli, M. Fiaschi, Gino Dini, F. SarriAbstract:Abstract This paper presents an experimental design approach to process parameter optimization for the laser welding of martensitic AISI 416 and AISI 440FSe stainless steels in a constrained overlap configuration in which outer shell was 0.55 mm thick. To determine the optimal laser-welding parameters, a set of mathematical models were developed relating welding parameters to each of the weld characteristics. These were validated both statistically and experimentally. The quality criteria set for the weld to determine optimal parameters were the minimization of weld width and the maximization of weld penetration depth, resistance length and Shearing Force. Laser power and welding speed in the range 855–930 W and 4.50–4.65 m/min, respectively, with a fiber diameter of 300 μm were identified as the optimal set of process parameters. However, the laser power and welding speed can be reduced to 800–840 W and increased to 4.75–5.37 m/min, respectively, to obtain stronger and better welds.
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Experimental investigation on laser beam welding of martensitic stainless steels in a constrained overlap joint configuration
Journal of Materials Processing Technology, 2010Co-Authors: M.m.a. Khan, Luca Romoli, M. Fiaschi, F. Sarri, Gino DiniAbstract:Abstract This paper presents experimental investigation of laser beam welding of martensitic stainless steels in a constrained overlap configuration. Experimental studies were focused on the effects of laser power, welding speed and fiber diameter on bead geometry and mechanical properties of the weld. Metallurgical study of a selected welded joint was done only to show various microstructures typically formed at different zones. Laser power and welding speed were found the most significant factors affecting the weld geometry and Shearing Force. The contour plots showing constant response lines indicated the evidence of two-factor interaction effects of laser power-welding speed, welding speed-fiber diameter, and fiber diameter-laser power on all the responses except the weld width. Moreover, energy density plots illustrated its linear relationship with penetration depth and limited nonlinear effects on others. Additionally, metallurgical analysis of fusion zone showed dendritic structures consisted of martensitic with eutectic ferrite along solidification grain and subgrain boundaries.
