Fig.5 Compressive stress-strain curves of all specimens (a) Monotonic
loading condition (b) Cyclic loading condition
This is further confirmed by the fracture plane images as shown in Fig.
6a. The cubic irregular structure haa a well-defined and longer plateau
compared to the cubic regular structure. This is due to the presence of
inclined struts from the displaced nodes. This irregularity decreases
the maximum stress that can be sustained by the structure but avoids the
sudden failure of regular cubic structures. The fracture plane shown in
Fig. 6b indicates a failure plane similar to a shearing band. The
star-based topology structure has a plateau region similar to that of
cubic irregular structures. The presence of struts in the oblique
directions along with the vertical struts decreases the maximum stress
that can be sustained when compared to the cubic regular structures
which had struts in the vertical direction. However, the oblique struts
assist in bearing the load once the vertical strut fails. While
considering the star regular and star irregular stress-strain curves,
the presence of irregularity has a clear effect on the stress sustained
by the structures while the length of the plateau region is unaffected.
It is seen from Fig.6c and 6d that the vertical struts fail, but the
failure happens along a 45ยบ shear plane.