纯弯状态下蜂窝梁腹板的弹性屈曲分析

ELASTIC BUCKLING ANALYSIS OF WEB OF CASTELLATED BEAMS UNDER PURE BENDING

针对蜂窝梁腹板在纯弯状态下的弹性屈曲,利用ANSYS 15.0建立了正六边形孔蜂窝梁腹板在纯弯应力状态下的有限元模型,研究了四边简支开孔板在纯弯状态下的屈曲模式,分析了孔洞尺寸对蜂窝梁腹板屈曲临界应力的影响,提出了纯弯状态下开孔板的屈曲系数计算式,得到了蜂窝梁开孔腹板在纯弯状态下的高厚比限值。研究表明:无论开孔数目多少,最大平面外屈曲位移均发生在各孔洞正上边缘;蜂窝梁腹板高厚比是影响开孔板屈曲临界应力的主要因素,建议对于弯矩作用较大的蜂窝梁腹板取0.6<γ<0.7,0.7<β<0.8的孔洞尺寸容易实现稳定性和经济性要求(γ为孔高比,β为距高比);拟合出的开孔板屈曲系数计算式,误差不超过5%,具有良好的精度。

For the elastic buckling of web of castellated beams under pure bending,the finite element model of the web of castellated beams with hexagonal holes under pure bending was established by ANSYS 15.0,and the buckling modes of perforated plate which was simply supported on four sides were studied in detail.And the influence of the hole size on the buckling critical buckling stress of perforated plates was also analyzed.On the base of the calculation formula of solid plate＇s buckling coefficient,a formula was put forward to calculate the buckling coefficient.And the limitation of heightwidth ratio of a perforated plate under pure bending was obtained.According to these researches,no matter how many holes are,the largest out-of-plane buckling displacement always happened right above the holes,and the height-width ratio of a perforated plate is the main influencing factors to the critical buckling stress.It is suggested that the ratio of holes height to plate height value range is from 0.6 to 0.7,while the ratio of distance between the adjacent holes to plate height value range is from 0.7 to 0.8,so that it can satisfy the request of the stability and economy.According to the verification,the formula has good accuracy with the error is not more than 5%.