相移法获取三维光弹特征相位差的方法

Evaluating characteristic retardation in three-dimensional photoelasticity by phase shifting technique

对于三维光弹模型,次主应力及其方向沿入射光连续变化,根据光学等效的原理,可以将三维光弹模型等效为一个包含线性相位延迟器和旋光器的光学模型。在集成光弹法中,对于每一个测量点,研究者必需通过实验获取三个特征参数。提出了一种用于确定集成光弹中全场特征相位差的五步相移法,给出了偏振光场中元器件的设置方法,并运用Jones算子推导出相移法得出的光强公式。最后使用斜射法对径向受压圆盘进行实验,验证了方法的有效性。

A general three-dimensional photoelastic model with varying secondary principal stresses difference and their directions along a given light path can be replaced by an optically equivalent model consisting of a linear retarder and a pure rotator. In integrated photoelasticity, one has to determine three characteristic parameters experimentally for any test data point. A whole field technique for determination of characteristic retardation in integrated photoelasticity using five-step phase shifting methodology is proposed. Appropriate optical arrangements necessary for this are presented and the expressions are derived using Jones＇ calculus. An example of a circular disk under diametral compression viewed in oblique incidence is used to demonstrate the procedure.