Study On Clamping Force And Critical Axial Force Of The Bare Rod Blank In The Elasto-plastic Clamping State

In the forming process of full-fiber crankshaft, the shaft shoulder type structure of blank material is mainly pre-machined, in order to facilitate the clamping and positioning. However, the metal fiber of blank is cut off while the shaft shoulder is processed, it undermines the fiber structure of the crankshaft. To a certain extent with the method of directly blank clamping, it can avoid the metal fiber mechanically cut caused by discontinuities because shaft shoulder dosen’t need to be processed. It’ll lead to axial movement of the blank because clamping force is not insufficient in the upsetting process. The accuracy of the crankshaft will be impacted because of positioning allowed. Therefore, in the full-fiber crankshaft upset forging process, the blank clamping is an important problem to be studied. In this paper, using the finite element method to establish the model of blank clamping, conducts the study to the clamping force and the critical axial force of the bare rod blank in the condition of elasto-plastic contact.The tooth jaws with round corner and trapezoidal are selected in the paper. The bare rod blank is established by using the finite element software. The clamping force and the critical axial force are studies on the influence of fillet radiuses or length tooth tips of the tooth jaws, the amount of pressure of the tooth, the yield strength of the material, the elastic modulus of materials, the coefficient of friction of the five influence factors. Using numerical simulation result combined with BP neural network, the paper predicts the clamping force and critical axial force.The clamping force and critical axial force have carried on the experimental study. Multiple sets of tooth jaws with round corner of different fillet radiuses and trapezoidal tooth jaws with different length tooth tips are designed. Two kinds of materials that Q235 steel and 2024 aluminum are experimentally about the clamping condition to analyze the clamping force and critical axial power in the impact on different reduction of jaw tooth. Experimental results and numerical simulation results coincide.