基于应变模态的连续梁动挠度识别

为了实现基于应变测量的连续梁动挠度识别，提出了一种基于应变模态的梁结构动挠度监测方法。利用应变传感器进行应变测试获得梁的动应变数据，由动应变数据的互相关函数求出应变模态振型，利用应变-位移转换关系求出位移模态振型，再由动应变数据和应变模态振型计算出位移模态坐标，最后根据计算出的位移模态坐标叠加位移模态振型得到梁结构的实时挠曲线，从而实现对动挠度的监测。为了验证方法的有效性，对连续梁在脉冲激励及地震作用下的动挠度进行了数值模拟，并进行了简支梁力锤锤击实验。数值模拟及实验的结果表明，基于应变模态监测梁结构动挠度是可行的，且具有较高的精度。

STRAIN MODES BASED DYNAMIC DEFLECTION ESTIMATION OF CONTINUOUS BEAM STRUCTURES

To identify the dynamic deflection of continuous beam structures based on their measured strains, a new technique to estimate the dynamic deflection of beam structures based on strain modes is proposed. The strain mode shapes are first estimated from the cross-correlation function of measured dynamic strain data. Then, the displacement mode shapes can be estimated from the strain mode shapes based on a displacement-strain relation. With knowing the strain mode shapes and strain data, the corresponding modal coordinates can be estimated. The dynamic deflection can then be estimated by the obtained displacement mode shapes and modal coordinates. The method is verified by numerical simulations of a simply support beam subjected to an impulsive excitation and an earthquake excitation. The experimental tests of a simply supported beam under various hammering excitations are also conducted to verify the effectiveness of the proposed method. Both the numerical and test results show that the proposed method can estimate the dynamic displacement of beam structures with a high accuracy.