Page 54 - eBook_Proceedings of the International Conference on Digital Manufacturing V2

Proceedings of the International Conference on Digital Manufacturing –
Volume 2

The Regression Analysis was done to predict maximum stress
on the application of displacement. These equations in Table 7 are
constraints for three-point bending tests on PLA only. In this
regard, different infills lattice structures produced different
equations. BCC, FCC, TRI HC, Fluorite, Diamond and Gyroid
show the linear relation for stress and strain while the Kelvin, and
HX HC show the linear power best fit for both in Strains and
Stresses.

RESULTS AND DISCUSSION

Equivalent Stress

Equivalent stress analysis reveals that the Triangular Honeycomb
(TRI HC) lattice, although not demonstrating the minimum stress
value, is an excellent performer in most parameters. This suggests
that its structure, as a hexagon feature, offers a perfect balance of
mechanical properties. Di symmetric lattice structures, as is the
case with TRI HC, are usually a good compromise between
stiffness and strength, making them an excellent choice for
applications where load capacity is critical.

One of the most noticeable features is the presence of sudden
changes in stress at the contact points between the rollers and
beam shell. These concentrations of stress are localised and a
characteristic of typical FEA simulations due to how the mesh is
formed and the nature of concentrated loads. In real life, such
stress concentrations would lead to premature failure, and this is
to highlight the need for design modification to minimise this
effect.

Equivalent Strains

The calculated values of strain in observation tend to be within the
expected ranges, implying that the simulation is behaving
naturally and the material response is within the elastic range.
Interestingly, the TRI HC lattice, once again, does well in this
calculation. Its behaviour is one where there is a linear relationship

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