Showing 4 results for P. Davami
N. Hatami,, R. Babaei, P. Davami,
Volume 5, Issue 2 (spring 2008 2008)
Abstract
Abstract: In this study an algorithm for mold-filling simulation with consideration of surface
tension has been developed based on a SOLA VOF scheme. As the governing equations, the
Navier-Stokes equations for incompressible and laminar flows were used. We proposed a way of
considering surface tension in mold-filling simulation. The proposed scheme for surface tension
was based on the continuum surface force (CSF) model we could confirm the remarkable
effectiveness of the surface tension by experiment which concluded in very positive outcome.
A. Mohassel, A. H. Kokabi, P. Davami,
Volume 8, Issue 4 (december 2011)
Abstract
The wide-gap aluminothermic rail welds with root opening of 50-70 mm were produced using plain carbon steel rail and non-alloy aluminothermic charge. Mechanical properties and micro-structure of the weld metal and HAZ as well as the impact energy and the fracture toughness of the welds were investigated. The yield and tensile strength of wide-gap welds were about 98% and 95% of the base metal, respectively. Both minimum and maximum hardnesses of the joint were seen in HAZ which were related to the grain coarsening and normalizing, respectively. The mean value of wide-gap weld fracture toughness is more than narrow-gap weld. Moreover, trans-granular cleavage indicated the brittle fracture mode of the weld metal.
A. Fardi Ilkhchy, N. Varahraam, P. Davami,
Volume 9, Issue 1 (march 2012 2012)
Abstract
Abstract: During solidification and casting in metallic molds, the heat flow is controlled by the thermal resistance at the casting-mold interface. Thus heat transfer coefficient at the metal- mold interface has a predominant effect on the rate of heat transfer. In some processes such as low pressure and die-casting, the effect of pressure on molten metal will affect the rate of heat transfer at least at initial steps of solidification. In this study interfacial heat transfer coefficient at the interface between A356 alloy casting and metallic mold during the solidification of casting under pressure were obtained using the IHCP (Inverse Heat Conduction Problem) method. Temperature measurements are then conducted with the thermocouples aligned in the casting and the metallic mold. The temperature files were used in a finite-difference heat flow program to estimate the transient heat transfer coefficients. The peak values of heat transfer coefficient obtained for no pressure application of A356 alloy is 2923 and for pressure application is 3345 . Empirical equation, relating the interfacial heat transfer coefficient the applied pressure were also derived and presented.
A. Khakzadshahandashti, N.varahram, P. Davami,
Volume 11, Issue 2 (June 2014)
Abstract
This article examines the Weibull statistical analysis that was used for investigating the effect of melt
filtration on tensile properties and defects formed inside the casting. Forming and entrapping of double oxide films
have been explained by using the context of critical velocity of melt in the runner. SutCast software results were used
to examine the amounts of the velocity of melt as such. SEM/EDX analysis is used to observe the presence of double
oxide films in the fracture surfaces of the tensile specimens. The article goes on to propose that castings made with
foam filters with smaller pores show higher mechanical properties and reliability due to higher Weibull modulus and
fewer defects
