Manufacturing Simulation Using Finite Element - Finite Element Analysis for Satellite Structures - page 285

Fig. 7.14 Isight flowchart to
model the shot peening
process
details due to the shot impact. By local details, I mean the indentation due to
impact, and the interaction with the subsequent manufacturing process that may
lead to crack initiation. Which leads to a more complex scheme to model the shot
peening process by using explicit finite element method, which was developed by
Wang [ 21 ]. So, if the shot peening simulation intends for design optimization of
the process parameters, then the thermal equivalent should be used. If the simu-
lation intends to study the local effects of the process, such as crack initiation due
to subsequent manufacturing process, then the explicit finite element scheme
should be applied. In this section, the explicit finite element scheme is discussed in
details using ABAQUS, MATLAB, and Isight. If the reader is interested in
experimental study of shot peening and stress peen forming, then he should check
the work done by H.Y. Miao [ 22 ]. They studied the relationships between the
saturation, surface coverage, and roughness with respect to peening time, using
aluminum Al2024 test strips. The influences of peening velocity and peening time
on the resulting residual stress profiles have been experimentally presented. It
would be an interesting project for the reader, if the finite element scheme
described in the next section is applied on similar Al2024 samples and results are
compared.
7.3.1 Finite Element Model
Wang [ 21 ] created the shot stream by modeling a series of impacts that covers
4 (n-1) impacts at a specific step n. This virtual coverage can model the progress of
a single impact to a large number of multiple impacts. The first analysis step
simulates the impact of one shot at the middle of the plate. Then, the second step
analysis simulates the impact of additional 4 (1) impacts. Followed by other steps
that simulate the impact of extra 4 (n-1) shots, until the number of impacts is
covered. Simulation of shot peening is performed one by one, while including the
residual stresses and deformations from previous impacts. A sequence of shot
impacts uniformly distributed in both space and time is created. At each analysis
step, the impact location begins from the smallest coordinates x and y, then
increments y of the impact location while its x is fixed. Once the impact location
reaches the edge of the panel, x is incremented and y starts from its smallest value.