Abstract: Hydroforming of aluminum sheets is a plastic deformation process largely used in automotive industry. Among the different hydroforming processes, the Flexform is the one in which the punch is replaced by a fluid cell. This cell consists of a rubber membrane that is filled with a controlled pressure fluid that will deform the sheet in the tool. A rigid die is used for obtaining the shape of the workpiece. For obtaining a sound product a balance between the pressure fluid and the blank material and geometry must be assured. The paper presents experiments carried out for analyzing the influence of the die geometry, the blank thickness and the fluid pressure toward the product accuracy, in terms of thickness and shape variations. The results will be useful in process modeling and in estimation of hydro-deformability of aluminum sheets.

• Publication Date: 29-Apr-2018
• DOI: 10.15224/978-1-63248-150-4-47
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Abstract: Complicated behavior of oilwell drill string with both torsional and lateral whirl vibrations are explored numerically and experimentally within this paper. A modified Jeffcott rotor model with attention to drill string and outer shell interactions is developed. Drill mud drag forces within a thin annular film surrounding the vibrating rotor are considered. With respect to the rotation speed drill mud damping effect on drill string behavior is studied. Numerical efforts are compared to experimental studies conducted with laboratory scale drilling system. The results obtained suggest that the drill mud dynamics are highly related to the drive speed and rotor deflection. The findings of this work are relevant to the understanding of hydrodynamic mass of drill muds on drill string dynamics and schemes for controlling them.

• Publication Date: 29-Apr-2018
• DOI: 10.15224/978-1-63248-150-4-48
• Views: 0
• Downloads: 0