We present direct numerical simulations of Boussinesq and non-Boussinesq Rayleigh–Bénard convection in a rigid box containing a perfect gas. For small stratifications, which includes Boussinesq fluids, the first instability after steady rolls was an oscillatory instability ~a Hopf bifurcation!. The resulting convection was characterized by two hot and two cold blobs circulating each convective ...

ABSTRCT: High-speed cold roll-beating forming technique is a new near-net plastic forming method that the intermittent high-speed roll-beating is used to achieve dynamic impact local loading, and that is fast, transient, high impact, large deformation of the complex forming process. For this forming process, the main stress method is employed to derive an analytic formula for the deformation fo...

In this study, "Buckling Limit of Strain" (B.L.S.) is introduced as one of the most important limiting factors in cold roll forming process. B.L.S. is calculated by the finite element procedure. Then for two particular processes with existing analysis and experimental results, B.L.S. has been determined and evaluated. LUSAS 12.3 is used for finite element analysis. The results show that when bu...

In this article, stress analysis and energy estimation during cold-roll forming of symmetrical channel sections have been discussed. Geometry of sheet strip is pre-estimated by a shape function. Then longitudinal, transversal and shear strains have been calculated. Using both the Levy-Mises and the Prandtl Reuss equations, and also considering the Bauschinger effect, stress distributions have b...

In this study, Buckling Limit of Strain (B.L.S.) is introduced as one of the most important limiting factors in cold roll forming process. B.L.S. is calculated by the finite element procedure. Then for two particular processes with existing analysis and experimental results, B.L.S. has been determined and evaluated. LUSAS 12.3 is used for finite element analysis. The results show that when buck...

In the present study, the presence of brass mesh on the bond strength of aluminum (AA1050) strips in the cold roll bonding process was investigated. The influence of various process parameters including reduction in thickness, pre-rolling annealing, initial thickness of the strips, and post-rolling annealing was also considered. After cold roll bonding process, peeling test was carried out and ...

cold roll-forming is a process in which the roll of sheet is formed by passing continuously through the set of rotary rollers without changing thickness in a cool way until it is formed to the desired profile. in this paper a parametric study on the section twist angle in roll-forming the non-symmetric channel is presented, using finite element simulation. at first finite element simulation res...

Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produc...