Measurement of Orthogonal Stress Gradients Due to Impact Load on a Transparent Sheet using Digital Gradient Sensing Method
Measurement of Orthogonal Stress Gradients Due to Impact Load on a Transparent Sheet using Digital Gradient Sensing Method
复制标题
DOI：
10.1007/s11340-012-9653-x
复制
发表时间：
2013-01-01
影响因子：
2.4
通讯作者：
Tippur, H. V.
中科院分区：
文献类型：
--
作者：
Periasamy, C.;Tippur, H. V.
提出了一种用于测量平面透明薄板在冲击载荷作用下应力梯度的全场光学方法--数字梯度传感法（DGS）。该技术是基于透明固体所表现出的弹性光学效应，由于施加的应力场导致使用2D数字图像相关方法量化的光线的角偏转。在平面应力条件下，测得的角偏转与平面内应力梯度成比例。该方法实现相对简单，能够同时测量两个正交方向上的应力梯度。这种方法来研究材料的失效/损伤的可行性证明了透明的平面片的PMMA进行准静态和动态线载荷作用在一个边缘。在后一种情况下，超高速数字摄影用于执行时间分辨测量。准静态测量成功地比较与那些基于Flamant解决方案的线荷载作用在半空间的区域，其中平面应力条件占上风。动态测量，材料失效之前，也成功地与有限元计算相比。文中还给出了损伤起始后撞击点附近的应力梯度，并讨论了其破坏行为。
A full-field optical method called Digital Gradient Sensing (DGS) for measuring stress gradients due to an impact load on a planar transparent sheet is presented. The technique is based on the elasto-optic effect exhibited by transparent solids due to an imposed stress field causing angular deflections of light rays quantified using 2D digital image correlation method. The measured angular deflections are proportional to the in-plane gradients of stresses under plane stress conditions. The method is relatively simple to implement and is capable of measuring stress gradients in two orthogonal directions simultaneously. The feasibility of this method to study material failure/damage is demonstrated on transparent planar sheets of PMMA subjected to both quasi-static and dynamic line load acting on an edge. In the latter case, ultra high-speed digital photography is used to perform time-resolved measurements. The quasi-static measurements are successfully compared with those based on the Flamant solution for a line-load acting on a half-space in regions where plane stress conditions prevail. The dynamic measurements, prior to material failure, are also successfully compared with finite element computations. The measured stress gradients near the impact point after damage initiation are also presented and failure behavior is discussed.