Finite Element Analysis And Study On The Characteristic Stiffness Of The Multi-cored Forging Hydraulic Press

Oil and gas is the main source of energy around the world. The efficiency of itsexploiting and the exploitation quality directly affect the economic development of thecountries and the comprehensive national strength. Drill pipe joints for oil are an importantcomponent when producing oil and gas. The exploitation environment of oil and gas is bad, sothe quality of drill joints directly affect the efficiency of exploitation.Hydraulic press is an important equipment to produce oil drill pipe joints. The quality ofthe drill pipe joint is mainly determined by the hydraulic press. It has important significancestudying on the hydraulic press producing the drill pipe joint.，In this paper, taking themulti-cored forging hydraulic press as the typical prototype, the forces and the deformationswere analyzed when the hydraulic was in working state.，Besides, Model analysis of the maincomponents of the hydraulic press body were proceeded to find out a way of expressing thehydraulic press characteristic stiffness.1. Simulate the multi-cored forging hydraulic press in the working state. The structure ofthe multi-cored hydraulic press is complex compared to the general terms. The force is alsocomplex. Through the finite element analysis, we got the deformation trend of the hydraulicpress in working state which can be as the bases improving the stiffness of the press. Itincludes two steps when the press is producing the oil drill pipe joints. The first step is that themaster cylinder move down and the dies close. Then the side cylinders squeeze to make metalin the die deforming. In this paper, considering the bolt pretensions, mold station and so on inthe working conditions, the deformation of the press frame loaded the force at the maximumwas analyzed. That provides theoretical bases for designing the press.2. Modal simulation of the multi-cored forging hydraulic press was conducted. Createthe simplified model including top rail, bottom rail, column, slider with cylinder, moldworking table etc. Modal analysis of the press with bolt pretensions and the working load wasconducted through which we got the dangerous mode shapes and the positions and referencewas made in the design of the hydraulic press. It showed that the natural frequency is muchlarger than the minimum operating frequency when the press is working, so there was noresonance.3. Present a numerical analysis method to describe the characteristic stiffness of thehydraulic machine. To find the same quantity to show the stiffness of the complex structure ofthe hydraulic press, dynamics analysis of top rail, bottom rail, slider with cylinder, columnwere conducted. Based on the numerical results of the modal analysis and the orthogonality ofthe natural frequencies, the numerical solution describing the stiffness can be obtained whenput the simplified rod and beams into a mathematical expression. The method provides the new criterion to optimize the stiffness of the press.