深孔钢闸门组合截面主梁应力计算方法

Calculation of Stress for Composite Walled Main Beam of Deep-hole Sluice Gate

为了解决以往深孔钢闸门主梁弯曲正应力沿用细长梁理论其计算结果偏于危险,而有限元法计算工作量大且复杂的问题,因此,基于弹性理论,推导出了均布荷载作用下工字型截面梁纵向纤维挤压应力计算公式,以及考虑纵向纤维挤压和剪切翘曲影响的弯曲正应力计算公式,并提出了组合截面薄壁深梁的判定准则,并以有限元数值模拟结果为准对各种弯曲正应力解析计算方法进行了评价.结果表明:已有解析法误差较大,不能准确揭示组合截面薄壁深梁弯曲正应力的变化规律;而所提方法考虑了剪切翘曲及层间挤压的双向应力状态影响,计算结果精度较高且适用范围更广.

In order to solve the problem of deep-hole sluice gate in the main beam of previous slender beam theory which the calculation is unsafe and the finite element(FE)method is computationally expensive and conceptually complex,a new concise and accurate analytic approach is desirable for this specific cross-sectional design.Based on the theory of elasticity,formulas for the calculation of longitudinal compressive stress of an I-beam with a uniformly distributed load as well as for the calculation of bending normal stress,while taking into account the longitudinal fiber extrusion and shear warping,were derived.Furthermore,determination criteria for composite thin-walled deep beams were proposed and various analytical methods for bending normal stress calculation were evaluated based on the FE numerical simulation results.The results demonstrate that the existing analytical methods produce fairly large errors and cannot accurately reveal the pattern of being normal stress variation of composite thin-walled deep beams,whereas the method developed in this research,by considering sheer warping and interlayer extrusion under biaxial stress state,is able to generate more accurate calculation results with an extended scope of application.