rupture and wrinkling are two prevalent phenomena that happen in hydro-forming process. many efforts have been made to achieve the upper and lower bounds for the pressure related to rupture and wrinkling of sheet, respectively. the aim of this investigation is to improve the upper bound of fluid pressure in hydro-forming process by hemispherical punch. in this article, analytical study of the u...

The four processes involved in the flammability of materials are described and related to the various flame retardance mechanisms that may operate. Following this the four practical approaches used in improving flame retardance of materials are described. Each approach is illustrated with a number of typical examples of flame retardants or synthetic procedures used. This overview of flammabilit...

Extinction limits and flame bifurcation of lean premixed dimethyl ether-air flames are investigated numerically using the counterflow flame with a reduced chemistry. Emphasis is paid to the combined effect of radiation and flame stretch on the extinction and flammability limits. A method based on the reaction front is presented to predict the Markstein length. The predicted positive Markstein l...

Semi-solid forming processes are now used for producing near net shape parts especially in the automotive and aircraft industries. Non Newtonian rheology of semisolid alloys and its dependence on the various parameters such as reheating cycle, method used to produce non-dendritic structure, thermo-shear history etc. have made the simulation of the flow behavior of semisolid material a difficult...

          USD7 is one of the steel products of Isfahan Steel Company. It is cast in continuous casting moulds and rolled up to a rod of 5 mm diameter. Finally, it is wire drawn up to 3 mm and used as welding electrodes. This steel contains 0.05 to 0.09 wt. % carbon. The acceptable limit of the aluminium in this class of steel is less than 0.003 wt%. Therefore, it is categorized as rimmed steel...

This paper investigates the forming of sheet metal forming under cycling loading by considering the Bauschinger effect. Different proposed plasticity models which can handle this kind of deformation process have been reviewed in details. For instance, isotropic, kinematic and combined forms in the linear and non-linear cases including the well-known Yoshida and Chaboche's models have been studi...