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- 2019
集中冲击荷载作用下修正Timoshenko梁剪力动载系数研究Keywords: 修正Timoshenko梁, 集中力冲击荷载, 动力响应, 剪力动力荷载系数 Abstract: 推导了修正Timoshenko梁运动方程正交条件,并在此基础上得到了梁在跨中冲击荷载作用下的剪力响应计算方法。根据该方法计算的结果与经典Timoshenko梁理论计算结果对比,发现在梁长细比较小的情况下采用修正Timoshenko梁理论计算结果更精确。采用该方法得到了不同长细比固结梁和简支梁在跨中无增长时间三角形和有增长时间三角形集中力冲击荷载作用下的最大剪力动力荷载系数(DLF),并拟合出计算公式,可根据梁长细比和荷载持续时间与构件第一阶自振周期的比值来计算最大剪力动载系数,并用来确定墩柱等构件在冲击作用下的抗剪需求。Abstract:Orthogonality conditions of a modified Timoshenko beam were derived, and then its shear response calculation method under a concentrated impact load at its mid-span was deduced.The calculated results using this method were compared with those using the classical Timoshenko beam theory.It was shown that the calculation results using the modified Timoshenko beam theory are more accurate when the beam’s slenderness ratio is smaller.Using this method, the maximum shear dynamic load factors (SDLFs) of a two-end fixed beam and a simply supported one with different slenderness ratios under a concentrated impact load impulse with and without a triangular time history at the beam mid-span were calculated, and the calculation formula was fitted.It was shown that the maximum SDLF can be calculated according to a beam’s slenderness ratio and the ratio of the load duration to the beam’s 1st order natural vibration period, the maximum SDLF can be used to determine the anti-shear demand of a beam under impact load.
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