Manufacturing Simulation Using Finite Element - Finite Element Analysis for Satellite Structures - page 280

Fig. 7.7 Rivet formation
under impact force

T=4.5e-4 sec T = 1 e-3 sec

T = 2 e-3 sec

T = 1.5e-3 sec

0.5 ms. These values will make some ask questions about how did we come with
these values?. The answer is simply, we came with these values by trial and error until
we found the best match with the experimental results. Measuring these values is a
very difficult task and instead, the voltage of the LVER is used as an input to deform
the rivet. The rivet expansion limits in the radial direction is of the order of 0.3 mm.
The deformed process is shown in Fig. 7.7 at selected times. As the die squeeze the
rivet and due to the high strain rate, 90 % of the strain energy is converted to heat
energy. This rise in temperature leads to lower yield stress and the rivet head is
deformed softly under squeeze pressure and follow the die curvature. Excluding the
temperature effect on the material yield will produce different numerical results and
should not be ignored. Temperature profile at selected node adjacent to the die versus
time is shown in Fig. 7.8 .