贴片光弹法是一种通过精确测量表面应变来获得应力的光测实验方法。为了有效且快速的评价螺栓预紧力,采用贴片光弹的方法,在螺栓头部表面粘贴一片环氧树脂材料,对螺栓施加一定的预紧力时,在反射光弹仪的偏振光场下直接可以观测到螺栓头部贴片中的光弹条纹。随着螺栓预紧力的变化,条纹相应发生改变,从而获得螺栓预紧力与光弹贴片中条纹级数的关系。由于该方法具有灵敏度高、直观、全场、简单等诸多优点,适合现场测量和检测,从而便于推广。
Coating photoelasticity is a special technique for accurately measuring surface strains to deter- mine the stresses in a part or structure during static or dynamic testing. With the coating photoelasticity method, a piece of epoxy colophony coating is first bonded to the screw bolt's surface to value the screw bolt's pre-tightening effectively and rapidly. As the test or service loads are applied to the bolt, the strain on the surface are transmitted to the coating. The coating is then illuminated by polarized light from re- flection polariscope. With the change of load, the coating displays the strains (or stresses) in a colorful, informative fringe pattern, which is also changed immediately to reveal the relationship between grade of fringe and overall stress distribution and pinpoints highly stressed areas. Because of many strongpoints, such as high-sensitive, intuitionistic, full-field, simple etc., the coating photoelasticity method is suited to measure and inspect parts on the scene. So, it will be popularized easily and widely.