3.2. Three-layer composition of hard and soft material (Hcb +S+Hct)
Fig. 13 shows that the deflection decreases with the soft central layer
thickness increase. The behavior is similar to that of two-layer materials.
Also, the bendability coefficient confirms this fact (Fig. 14). Therefore,
we assume that the shape of force/deflection curves will be identical
to those for two-layer compositions.