结构局部应力场全景光弹测量方法研究

针对大型结构局部复杂应力场直观测量的需求,提出了全景光弹测试技术。在经典光弹实验系统中,偏振系统的大小限制了试件尺寸;同时理想光源系统的复杂性降低了实验测量的机动性。由于这两方面的限制导致经典光弹方法在测量大型复杂结构时存在较多的非确定性。为此建立了一个等效偏振系统,通过在试件表面镀制偏振膜的办法将偏振系统依附于试件表面,以解决试件尺寸限制问题。同时放弃了理想光源而采用自然光源,以提高测量的机动性。通过四点弯曲实验来检验本文方法的有效性。结果表明提出的测量技术是有效可靠的。利用本文提出的方法,对实际桥梁中缩尺试件的局部应力场进行了测量,得到了可用于结构模型修正的应力中心线信息。

Panoramic Photoelasticitic Method for Local Stress Field Measurement in a large span Structural

A panoramic photoelasticitic method was developed to measure the complex local stress field in a large span civil structure. In traditional photoelasticity, the scale of polarization system is too small to limite the specimen size, and the ideal light source system is too complex to reduce the maneuverability of measurement system. Above two factors could cause many uncertantities in scaled test for a large span civil structure by using traditional photoelasticity. A equivalent polarization system was established by plating polarization film onto the specimen surface, and the polarization system was attached to specimen to reduce the limit of specimen size. Light source also was expanded to natural light to improve testing maneuverability. Four-point beanding experiment by using panoramic photoelasticity was conducted to validate the efficiency of above proposed method. Results show that the developed system is more reliable. A scaled example from a real long span bridge was tested via above developed method, and its hot spot stress field was obtained for structural model updating.