Finite Element Analysis Of Rectangular Box Hydroforming Process And Design Of Relevant Experimental Instruments

Hydromechanical deep drawing is one of the special deep drawing processes which have been introduced to achieve higher tearing factors compared with those of the conventional deep drawing which used rigid tools. In the hydromechanical deep drawing, the sheet metal is pressed against the punch by the hydrostatic medium. According to the Coulomb's law of friction, the friction between the sheet metal and punch is increased by this. This makes greater depth possible. The elimination of the female die make the draw die set cost less than a conventional drawing die set does. The paper covers the finite element simulation (FEM) of the complete hydromechanical process for rectangular pieces with symmetrical geometry, performing process using the Dynaform-pc 5.1 of the explicit code LS-DYNA. The study focuses on two factors which are the path of hydraulic load and the path of binder force load. The rectangular pieces hydromechanical process starts with the precut sheet. First, the oil is pumped into the die; Then, the sheet is placed on the die; After that, the blank holder press down on the sheet; Finally, the punch is loaded on the sheet and the counter pressure is generated by penetration of the punch till the forming process finished. The study shows that a rational path of pressure load is a pivotal factor which can improve the forming condition in the process. The pressure load path and the motion path of punch are closely related. In order to get the best forming quality, the pressure load path must be controlled rationally. The blank holder is another vital factor. Not only the blank holder is used to prevent the wrinkling and cracking of the pieces, but also to seal the oil in the die so that higher pressure can be present. In the process of the rectangular box forming, the forming in different parts of the box is in different states of stress and strain. So the control of binder force according to different states is another key point in this study. On the basis of adoption of the knowledge of the hydroforming process and new devices invented recently abroad, the forming states of stress and strain in different parts of the box are analyzed in this study, and the forming device for the experiment is designed and manufactured, and the detector device is used to monitor the forming process. Also, there are many parameters that affect the process. In order to study the whole fact in this process, it is necessary to analyze every factor quantificationally. The tool parameters influence the forming process. So the economically changeable tool is considered in the design process. The study lays an important foundation for the succeeding multi-parameter experiment design and the study of the hydroforming process.