摘要
基于对蜂窝梁抗弯刚度准确值的确定,对蜂窝梁弯曲变形计算中抗弯刚度既有取值进行评价。费氏空腹桁架比拟法过去长期用于估计蜂窝梁的挠度,其抗弯刚度倒数按实腹截面和空腹截面取算术平均值。对比结果表明,采用该刚度算法普遍高估了实际值,其原因在于开孔削弱了实腹梁段的抗弯效率,并提出了增大空腹截面刚度权重的加权平均法,提高了计算精度。虽然空腹截面抗弯刚度低估了蜂窝梁平均刚度,鉴于其形式简单,提出了直接采取空腹截面刚度表达式但折减其孔高的计算方法,具有实用价值。采用本文方法所得抗弯刚度值可直接代入经典力学公式计算蜂窝梁和局部蜂窝梁的弯曲挠度。
The existing expressions for flexural stiffness of castellated beams are evaluated by comparison with their accurate values determined in a recent paper of the first author. The Vierendeel＇ s open - web truss analogy was used to predict the deflection of castellated beams. The reciprocal of flexural stiffness was conventionally taken as the arithmetic average of that for the open section and that for the solid one. It is found that such treatment always gives higher stiffness than the real one, and the overestimation is due to that the opening reduces the efficiency of the solid sections to resist bending moment. To improve the accuracy, a new formula of stiffness in the form of weighed average is proposed with superior weight to the open section. The expression of stiffness for the open section underestimates the stiffness of＇castellated beams. In view of its simple form, it is adopted to calculate the stiffness of castellated beams by reducing the depth of the holes in the expression and satisfactory results are achieved. The value of stiffness reckoned by the two approaches suggested in this paper can be inserted directly into the classical formula to determine the flexural deflection of castellated beams and beams with castellated parts.
出处
《铁道科学与工程学报》
CAS
CSCD
北大核心
2007年第1期72-76,共5页
Journal of Railway Science and Engineering
基金
湖南省建设科技计划项目(2004-25)
关键词
蜂窝梁
抗弯刚度
弯曲挠度
六边形孔
圆孔
castellated beam
flexural stiffness
flexural deflection
hexagonal hole
circular hole
