Research On Capability Of Pressure-Carring Of Viscous Medium With High Pressure

The new process of flexible die forming of sheet of viscous medium pressure forming is getting better development and application in aerospace felid for the dominances of complex shape parts forming in recent years. In the process of viscous medium pressure forming, which uses semi-solid, flow-able, high-viscous and strain-rate sensitive material as pressure-carrying medium. Non-uniform pressure field is formed during forming process and viscous adhesive stress is applied on the surface of specimen. It's necessary to study the performance of pressure-carrying of viscous medium for the control of viscous medium pressure forming process.In this paper, experimental and finite element methods are used to study the process of extrusion deformation of viscous medium with three different molecular weights. The intruding and extruding pressure and the variation of pressure difference between the tow pressures with the extrusion speed and extrusion ratio are analyzed. Results show the distribution of pressure of viscous medium has obvious pressure gradient and the pressure difference is bigger with higher viscosity of viscous medium.On the basis, carbonic acid esters are applied as tensile sample of viscous adhesive stress to carry out the experiments of influence factor of viscous adhesive stress. The variation of pressure difference of viscous medium with flow rate and the influence rule of pressure difference on the magnitude of extension of specimen are studied. The rule influence of viscous adhesive stress on the magnitude of extension of specimen is obtained by experimental measure and theoretical arithmetic. Results show the pressure difference in the channels is increasing as the increasing of flow rate, and the magnitude of extrusion of specimen is increasing as the increasing of pressure difference and interface adhesive stress.Comparison is carried out for the deformation specimen with viscous adhesive stress extrusion and the specimen with simple tension using photo-plasticity method. Results show the distribution of major shear strain with the tow models is very conform, which further verify the extension effect of viscous adhesive stress for sheet.