heory (HSAPT) to consider the transverse flexibility of the core.
They have supposed that the axial rigidity of the core is negligible
and found a distribution for the core's displacement components
when the structure is under static loading. Li and Kardomateas
(2008) tried to improve the accuracy of stress results by employing
polynomials of fourth and fifth orders for the core's transverse
and in-plane displacement, respectively. Although they have
increased the order of polynomial to enhance the accuracy, their
model is inaccurate in evaluation of transverse stress in the core.
Frostig (1999) used the same assumption of negligible circumferential
stress to study the bending of curved sandwich beams. He
proposed that the core's shear stress has inverse relation with the
square of radial coordinate and derived a new pattern for the core's
displacement components in curved beams. Bozhevolnaya and
Frostig (2001) applied the assumption of HSAPT to study the free
vibration response of curved beams. However, they used the
pattern, which was proposed by Frostig (Demasi, 2013), only for the
core's displacement components and assumed that its velocity and
acceleration components are linear polynomials of the radial coordinate.
Bozhevolnaya and Sun (2004) used the linear distributions
for the core's displacement components as well as the velocity
and acceleration components. They studied the effects of the
boundary conditions and curvature angle and reported that the
curvature angle has a key role in the vibration behavior of a beam
with fixed ends.