基于刚度相似的模型动力试验研究

Research on model dynamic tests based on stiffness similarity

在模型动力试验的基础上,对刚度相似进行了理论分析。选取同材料不同规格的三个钢管,做成刚度相近的三个模型,对模型做牵引释放试验,分别测量上部质量块的加速度、速度和位移。在钢管底部侧边粘贴竖向应变片测量底部的竖向动应变。模型的动力、应变衰减曲线表现良好,同时加速度、速度衰减曲线具有较好的相似性;相同力牵引释放下,刚度大的模型的加速度、速度和位移小。试验证明:在弹性范围内,模型间的加速度与速度基本符合刚度比的倒数关系,垂直于重力方向的动力模型试验可采用刚度相似模型进行,误差在5%以内。

On the basis of the model dynamic tests,the stiffness similarity was analyzed in theory.Three steel tubes in similar material but different specifications were selected to make three models with the similar stiffness similarity.Traction and release tests of the models were carried out and the acceleration,velocity and displacement of the upper mass were measured.A vertical strain gauge was stuck at the bottom of the steel tube to measure the vertical dynamic strain of the bottom.The dynamic attenuation curves and strain attenuation curves performed well.The attenuation curves of acceleration and velocity showed a good similarity.Under the same traction and release forces,the acceleration,velocity and displacement were smaller for the model with bigger stiffness.The tests prove that the acceleration and velocity of models at the elastic stage are in line with the reciprocal relationship of stiffness ratio.Dynamic model test perpendicular to the direction of gravity can adopt stiffness similarity model,and the error is within 5%.