正弯矩区组合梁腹板局部稳定性研究

STUDY ON LOCAL BUCKLING OF WEBS OF COMPOSITE BEAMS SUBJECTED TO POSITIVE BENDING MOMENT

对正弯矩区组合梁腹板局部稳定性进行研究,首先要建立板件在拉、弯、剪共同作用下的相关屈曲方程。该文在前人研究的基础上,根据能量方法研究了四边简支板件在拉、弯、剪共同作用下的弹性相关屈曲方程,并利用通用有限元软件ANSYS建模进行计算,验证了理论推导结果,最终提出简化公式。随后在相关方程的基础上,推导出相应的弹性高厚比限值。并将该限值与未考虑弯拉作用的限值进行对比,结果有明显提高,多数情况下可放宽26%以上。该文成果为进一步研究正弯矩区组合梁腹板考虑残余应力和初始缺陷的弹塑性屈曲提供基础。

Before studying the local buckling of webs of composite beams subjected to positive bending moment, the buckling interaction formulas of a simply supported rectangular plate subjected to combinations of tension, bending and shear stresses should be established. The interaction formulas of elastic buckling of such a plate are obtained through the energy method. The results are in an excellent agreement with those obtained from commercial finite element software ANSYS. A simple formula is then presented. Based on the interaction formula, the elastic limiting height-to-thickness ratio is given, which is also compared with the ratio without considering bending and tension. It is demonstrated that the height-to-thickness ratio obtained is increased, and in most cases, it is more than 30% larger. Results obtained provide a good foundation for the research of elasto-plastic buckling of webs of composite beams considering residual stress and initial imperfection.