Investigation of contact interface between the punch and blank in deep drawing process

الملخص EN

In this work a commercially finite element program code (ANSYS 5.4), is used to perform the numerical simulation of the deep drawing operation.

A simplified axisymmetric model of cylindrical cup of (44 mm) outer diameter, (28 mm) height and (0.5mm) sheet thickness of annealed mild steel of 0.15 % carbon content, has been developed, and the numerical results are compared with the experimental work.

Six types of punches of (43mm) diameter with punch profile (nose) radius of {P = 3, 6, 9, 15, 18, & 21.5 mm} have been constructed and used, and the value of die profile (nose) radius is kept constant to (d = 6mm).

This work aims to study the effect of punch profile radius on the interfacial contact between the punch and the blank, punch load, thickness variation over the produced cup wall, localized strains and stresses distribution across the inner and outer wall of the drawn part, the height and amount of spring back of the drawn part.

The results show that ; The length of contact distance between the blank and the punch increases as the punch nose increases and its value approximately is equal to punch nose radius.

Increasing the punch profile radius leads to increasing the cup height about (2 % for FE Simulation & 18 % for experimental work), and increasing the value of spring back to about (1.75 % for FE Simulation &1.25 % for experimental work)) for punch nose radius ranging from (3 to 21.5mm).

The greatest thinning is seen to occur with spherical punch due to great stretching of the blank over the punch head.

The punch load decrease slightly with increasing punch nose radius.

The more generous punch radius (spherical nose), the more gradual rise of the punch load and larger the punch travel.

The stress and strain distributions for all geometries chosen are similar in shape, and have the same trend and approximately the same values for both inner and outer wall of the drawn part.