Abstract:
Plastic waste causes serious environmental pollution and exhaustion of landfill space.
One of the main reasons for this plastic-based waste is the lack of a full recycling
process. In the recycling process shredding is one of the crucial stages where the main
size reduction takes place. The size reduction in single shaft shredder is done by shearing
and/or crushing the plastic between stationary blades that are bolted on to the casing and
rotating blades mounted on the rotor. In this thesis work the effort is taken on finite
element analysis, and design optimization of shredder rotor.
In the conceptual design, three concept variants, namely flat arrangement, scissor
arrangement, and staggered arrangement were considered and evaluated by assigning
performance criteria. According to the considered criteria, their weighting percentages
were found to be 65.42%, 64.42%, and 66.75% respectively. As a result, due to the higher
weighting the staggered arrangement is selected as an appropriate concept for further
analysis.
In the same manner for attaching the shaft with the blade carriage three different types of
shafts, namely, cylindrical, hexagonal, and splined shaft were considered and analyzed
on ANSYS®V19R1. The static structural analysis is conducted on three of them with the
same loading and boundary conditions. Accordingly, the maximum deformation result are
0.040 mm, 0.003 mm, and 0.028 mm whereas, the equivalent Von-Mises stress for
cylindrical, hexagonal, and splined shaft are 216.92 MPa, 45.483 MPa, and 45.478 MPa
respectively. As the splined shaft coupled with the blade carriage has lower deformation
and stress. Thus, it is considered as the best mechanism.
The topology optimization of blade carriage after smoothing resulted with 17.5% mass
reduction. For the parametric optimization of blade carriage of the rotor, five input and
three output parameters were considered to parametrically optimize the blade carriage.
From Design Exploration response surface, response surface optimization, were
conducted. The parametric optimization, which was conducted on the blade carriage
resulted in three candidate parameters from which the best candidate is used with little
approximation to remodel the blade carriage. The optimized parameters of the carriage
are P1=9mm, P2 = 52.5 mm, P4 = 31 mm, P5 = 51 mm, P6 = 162.5 mm.
