基于疲劳传感器的大型桥梁载荷谱检测研究

Study of Load Spectrum of Long-Span Bridge Based on Fatigue Life Gauge

提出基于同一倍增器上双疲劳计的桥梁载荷谱检测方法,将疲劳传感器上两个疲劳计以不同方向粘贴得到不同放大系数,由恒幅标定数据和等效原理用插值方法得到复杂加载下疲劳响应计算方法,并根据桥梁载荷谱的瑞利分布特点,得到该分布下的疲劳响应计算方法。采用倍增器的双疲劳计结构设计,利用疲劳计响应的非线性特性,得到疲劳传感器电阻变化与桥梁瑞利载荷谱的对应关系。本文疲劳试验表明,试验载荷谱与预测载荷谱相当吻合,所设计的疲劳传感器性能良好,能够满足桥梁疲劳载荷检测要求。该传感器的检测原理提供了一种新的工程疲劳检测方法,它较目前采用的其它方法效率高、精度好,适用于长期疲劳监测。

A method of loading spectrum prediction was developed based on resistance change response of double gauge. This two fatigue gauge was fixed on strain multiplier in different directions, so that, they had different sensitivities. Firstly, on the basis of fatigue life gauge response data that calibrated in the condition of constant amplitude loading, the complex fatigue loading response could be reached with the aid of data insertion and equivalent resistance change method. Secondly, by using this analytical mode, the Rayleigh density distribution, which is the loading characteristic of bridge structure response, was also conducted successfully. The corresponding relation between fatigue life gauge resistance change and Rayleigh distribution parameter was established by a calculation program with dual sensor design in a fatigue life gauge and its nonlinear character. In this paper, fatigue experiment results show that there is a good agreement between real load spectrum and predicting results. This fatigue life gauge has a good property and meets demand of bridge fatigue measurement. The fatigue sensor has developed a new engineering method of fatigue measurement. It has high efficiency and accuracy compared with other currently used methods, and is very suitable for long time monitoring of long-span bridge.