A general theory that taking into account the transverse deformation is developed for plane-curved, untwisted beams subjected to loadings that result in deformations in the plane of curvature. First, a new constitutive relation between stress resultants, moment resultants, mid-plane strains and deformed curvatures for a curved plate in established. This curved plate constitutive relation will provide the fundamental basis to the analyses of curved structures composing of isotropic or anisotropic materials. Then, the bending stress formula can be deduced from this new developed curved plate theory. The influences of the Poisson ratio and the geometric parameter of h/R ratio on the bending stress are discussed in the present paper.
