Issue 30

C.J.Su et alii, Frattura ed Integrità Strutturale, 30 (2014) 502-514; DOI: 10.3221/IGF-ESIS.30.61 505 BHF is a constant value, v d 0 F  therefore: π/4 0 sin- cos      T HE FINITE ELEMENT SIMULATION ANALYSIS OF THICK PLATE FINE BLANKING The model of finite elements analysis efore simulating the process of the fine blanking, the model of V-shaped ring gear blank holder should be built first. Li Chuanmin(2007) [11] found that because of the symmetrical structure, half of the model is adopted to save the time and RAM. AISI-20 steel with 8mm thick is used in the paper and the model is simulated by way of the double-side gear ring blank holder whose results are shown in Fig. 2. The simulating parameters are shown in Tab. 1. friction coefficient 0.12 Unit grid 3000 Step 0.002 The pressure/ KN 20 BHF/ KN 60 Figure 2 : Finite element model. Table 1 : Simulation parameters. Process simulation of the double ring gear pressure side From Fig. 3 (a) to (e) it can be seen that in the process of double ring gear blank holder blanking, the shear zone of hydrostatic pressure is significantly higher than other parts, and compressive stress is also larger near the punch and die cutting edge. When the punch is down to ½ of the material thickness, the pressure stress of the die cutting edge greatly decreases. When the material is broken, the compressive stress that shear zone materials bears is further reduced and the tensile stress appears in the die cutting edge of shear deformation zone material. The greater the compressive stress of materials deformation zone is, the more conducive it is to give full play to the material plasticity so as to inhibit the crack generation or expansion and guarantee high quality blanking section. Consequently when the material is broken, the tensile stress that exists in deformation zone exacerbates the material fracture. To sum up, if we want to obtain high quality punching parts with double ring gear blank holder blanking, we must try to increase the three to the compressive stress of material shear deformation zone. Because bilateral gear ring blank holder blanking, gear form, tooth height, pitch, the blank holder force and the blank holder force will have different influences on the hydrostatic pressure, we need to simulate and analyze the process parameters [12]. The impact of ring gear form on thick plate fine blanking Using the V-shape, a step shaped and the cone gear form to finite element simulation, the hydrostatic pressure distribution is shown in Fig. 4. As can be seen from the graph, the hydrostatic pressure distribution that V - ring produced is broad, almost filling the entire fine blanking zone. However, the step shaped and the circular cone gear ring only produce hydrostatic pressure in gear ring near, and the scope is relatively small. Although the step shaped and the cone B