Stress field tomography based on 3D photoelasticity
Stress field tomography based on 3D photoelasticity
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DOI：
10.1016/j.jmps.2007.06.004
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发表时间：
2008-03
影响因子：
5.3
通讯作者：
M. Wijerathne;K. Oguni;M. Hori
中科院分区：
文献类型：
--
作者：
M. Wijerathne;K. Oguni;M. Hori
提出了一种基于三维光弹性的层析成像应力场识别方法。基于三维光弹性一般反问题的二阶张量场层析方法被发现对光弹性观测的误差高度敏感。本文将平衡条件和线弹性理论引入常规张量场层析方法，发展了一种新的应力场层析方法，对光弹性观测误差具有较强的稳健性。这种新的应力场层析方法将未知的三维应力分布展开为一组独立的基函数的线性组合，并提出了一个新的反问题：基于光弹性观测来识别基函数的幅度。就像三维光弹性反问题一样，这个新提出的反问题也是非线性的、不适定的。与三维光弹性的传统方法不同，这些非线性和病态都可以使用载荷增量方法进行适当的处理。载荷增量法通过在足够小的外部载荷增量下进行光弹性观测，将非线性解空间切割成具有唯一解的段。数值和实验验证表明，这种新的应力场层析方法对光弹性观测的误差具有足够的稳健性，适用于实验应力测量。
A tomographic method for identification of stress fields based on 3D photoelasticity has been developed. A second order tensor field tomographic method based on the general inverse problem of 3D photoelasticity, previously developed by the authors, is found to be highly sensitive to errors in photoelastic observations. In this study a new tomographic method for stress field with fairly high robustness to errors in photoelastic observations has been developed by introducing both equilibrium condition and linear elasticity to the previously developed general tensor field tomographic method. This new stress field tomographic method expands unknown 3D stress distributions as a linear combination of independent set of basis functions and a new inverse problem is posed: identify the amplitudes of basis functions based on photoelastic observations. Just as the inverse problem of 3D photoelasticity, this newly posed inverse problem is also nonlinear and ill posed. Unlike conventional approaches to 3D photoelasticity, both these nonlinearity and ill-posedness are properly treated using a load incremental approach. Load incremental approach chops the nonlinear solution space into segments with unique solutions by conducting photoelastic observations at sufficiently small increments in external load. Validating both numerically and experimentally, it is shown that this new stress field tomographic method has sufficient robustness against errors in photoelastic observations and is applicable to experimental stress measurements.