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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。
In order to realize the dynamic deflection identification of continuous beam based on strain measurement, a dynamic deflection monitoring method based on strain mode is proposed. Using the strain sensor, the dynamic strain data of the beam are obtained. The strain mode shapes are obtained from the cross-correlation function of the dynamic strain data. The displacement modal vibration modes are obtained by using the strain-displacement transformation relationship. Then the dynamic strain data and strain Modal vibration mode to calculate the displacement modal coordinates. Finally, the real-time deflection curve of the beam structure is obtained by superimposing the displacement modal vibration modes according to the calculated displacement modal coordinates so as to realize the monitoring of dynamic deflection. In order to verify the effectiveness of the method, the dynamic deflection of continuous beam under the pulse excitation and earthquake is numerically simulated, and the hammering experiment of simply supported beam is carried out. Numerical simulation and experimental results show that it is feasible to monitor the dynamic deflection of beam structure based on strain mode, and it has higher accuracy.