When materials that exhibit different mechanical behaviors in tension and
compression must be analyzed, Ambartsumyan’s bimodular model for isotropic
materials can be adopted. It deals with the principal stress state in a point, which
is particularly important in the analysis and design of reinforced concrete
structures. However, due to the inherent complexity of the constitutive relation,
it is difficult to solve analytically for bending components with bimoduli
except in particular simple problems. Here we propose a simplified mechanical
model, based on the classical Kirchhoff hypothesis, used for the solution of the
bimodular thin plates in bending. We first use the Kirchhoff hypothesis to
judge the existence of the elastic neutral layers of bimodular thin plates in
small-deflection bending. Based on the existent neutral layers, we extend the
solution from the case of pure bending into the case of lateral force bending.
We use the displacement variation method to illustrate the application of
the proposed model, and compare it with FEM results strictly based on
Ambartsumyan’s materials model. The comparisons show that the proposed
mechanical model is valid and helpful for analyzing bending structures with
bimodularity.
Keywords
bimodulus, tension and compression, Kirchhoff hypothesis,
plates, neutral layer