单轴对称截面圆弧拱在局部区域径向均布荷载下的弯扭失稳

为了探究单轴对称截面圆弧拱的弯扭失稳行为,研究了局部区域径向均布荷载作用下单轴对称工字形截面两端铰接圆弧拱的弯扭失稳问题,考虑了剪切变形的影响,推导了失稳前拱的弯矩,轴力和剪力表达式。根据势能驻值原理和Rayleigh-Ritz法,得到了单轴对称截面圆弧拱弯扭失稳临界荷载理论解,并将其和有限元结果进行了对比。结果表明:当截面的较宽翼缘位于拱的顶部时,拱的弯扭失稳临界荷载值会增大;考虑剪切变形影响的浅拱的弯扭失稳临界荷载小于不考虑剪切变形的临界荷载;局部参数对拱的弯扭失稳临界荷载影响明显,弯扭失稳临界荷载随着局部参数的增大而减小。

Flexural-Torsional Instability of Circular Arches with Monosymmetric Section under a Localized Uniform Radial Load

In order to study the flexural-torsional instability behavior of circular arches with monosymmetric section, this paper focuses on the flexural-torsional instability of pin-ended circular arches with monosymmetric I-section under a localized uniform radial load. The pre-buckling bending moment, axial force and shear force of the arch were derived considering the effect of shear deformation. According to the principle of stationary potential energy and Rayleigh-Ritz method, the theoretical solutions for the flexural-torsional instability load of arch with monosymmetric section were obtained, which were compared with the finite element results accordingly. The results show that the instability load increases when the wider flange is located at the extrados and the instability load considering shear deformation is smaller than the one without including shear deformation for shallow arch. The influence of localized parameter on the instability load is obvious, and the instability load decreases with the increase of localized parameter.