FRACTURE PHENOMENON IN SIMULATION OF BIMETALLIC RODS EXTRUSION PROCESS

Mechanical behaviour of metallic material is different during its deformation as monometallic one in comparison with deformation as a component of composite. The different flow characteristics of two materials enhance the inhomogeneity of the extrusion process. This lead to poor tolerance throughout the extrudate fracture of the core or fracture of the sleeve. The concept of FEM Marc Mode has been presented with results which may indicate the possibility of assessment of existing fracture criteria for composite material. The present study shows that prediction based on the criterion including sigma(max),(sigma) over bar, (epsilon) over bar, epsilon(f) is reflected in experimental results. Fracture phenomena dependency occurring on geometrical arrangement of billet has been presented. The values of R-i/R-0 ratios were lower the probability of fracture occurrence was higher.