Abstract:
The problem of estimation of the bearing capacity of panels with a
folded filler from cardboard has been considered.
The strength and stiffness characteristics of the cardboard along
and across the fibers have been determined by testing the cardboard
samples for tension, compression, three-point bending, and shear.
The results of the experiments demonstrate that when the cardboard
is deformed after reaching a certain value, the yield surface is
observed. This enables us to calculate the structure of cardboard
according to the theory of limit equilibrium.
A model of deformation of the structure of a core from cardboard has
been constructed. A technique for estimating its ultimate load has
been developed. Based on the kinematic and static theorems of the
theory of limit equilibrium, the maximum load at which the structure
collapses is determined. The limiting load has been found using the
method of variation of elastic characteristics, which allows to
obtain the lower and upper bounds of the limiting load
simultaneously. As a criterion for cardboard strength, the Tsai–Wu
criterion has been used. To sample the calculation area, the finite
element method has been used.
The comparative analysis of the numerical calculations with the
results obtained from analytical formulas has been carried out.
Numerical experiments have been performed. The regularities of the
influence of geometrical parameters of the filler on the maximum
load of the structure have been revealed. The optimal parameters of
the geometry of the aggregate have been determined from the
condition of the minimum weight of the structure with its maximum
bearing capacity.
Keywords:limit load, experiment, identification, optimization, finite element method.
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