AN EXPERIMENTAL-STUDY ON TEARING ENERGY IN SPLITTING SQUARE METAL TUBES

An experiment was performed to study the tearing energy in splitting square aluminium and mild steel tubes of thicknesses ranging from 0.47 to 1.67 mm. It was carried out by driving four rollers each attached to the side wall of the tube, leading to the bending of the wall to a constant curvature and, at the same time, the tearing along the four corners. By pre-cutting some corners to a different length, the tearing energy involved was determined. It was found that the tearing energy per unit torn area (R) may be related to the ultimate stress of the material (sigma(u)) and the fracture strain (epsilon(f)) as R = 8.8sigma(u)epsilon(f) for mild steel and R = 37.2sigma(u)epsilon(f) for aluminium tubes; here the two coefficients have length dimensions in mm.