Performance Analysis of the Mesh‐Free Random Grid Method for Full‐Field Synthetic Strain Measurements

:  In responding to the needs of the material characterization community, the recently developed mesh-free random grid method (MFRGM) has been exhibiting very promising characteristics of accuracy, adaptability, implementation flexibility and efficiency. To address the design specification of the method according to an intended application, we are presenting a sensitivity analysis that aids into determining the effects of the experimental and computational parameters characterizing the MFRGM in terms of its performance. The performance characteristics of the MFRGM are mainly its accuracy, sensitivity, smoothing properties and efficiency. In this paper, we are presenting a classification of a set of parameters associated with the characteristics of the experimental set-up and the random grid applied on the specimen under measurement. The applied sensitivity analysis is based on synthetic images produced from analytic solutions of specific isotropic and orthotropic elasticity boundary value problems. This analysis establishes the trends in the performance characteristics of the MFRGM that will enable the selection of the user controlled variables for a desired performance specification.

[1]  Pieter J. Sevenhuijsen,et al.  The photonical, pure grid method , 1992 .

[2]  Harry Nyquist.  Certain Topics in Telegraph Transmission Theory , 1928 .

[3]  N. P. Andrianopoulos,et al.  An Approach to Analyse Errors Introduced in the Random Grid Strain Measurement Method , 2008 .

[4]  S. M. Chern,et al.  On Displacement Fields in Orthotropic Laminates Containing an Elliptical Hole , 2000 .

[5]  G. Marsaglia,et al.  A New Class of Random Number Generators , 1991 .

[6]  J. G. Michopoulos,et al.  A Computational Workbench for Remote Full Field 2D Displacement and Strain Measurements , 2009 .

[7]  Vincent J. Parks.  Strain Measurement Using Grids , 1982 .

[8]  Michel Grédiac,et al.  The use of full-field measurement methods in composite material characterization: interest and limitations , 2004 .

[9]  John G. Michopoulos,et al.  Performance Sensitivity Analysis of the Mesh-Free Random Grid Method for Whole Field Strain Measurements , 2008 .

[10]  Guriĭ Nikolaevich Savin,et al.  Stress concentration around holes , 1961 .

[11]  J. G. Michopoulos,et al.  Computational and Mechatronic Automation of Multiphysics Research for Structural and Material Systems , 2003 .

[12]  J. Michopoulos,et al.  Effects of Anisotropy on the Performance Sensitivity of the Mesh-Free Random Grid Method for Whole Field Strain Measurement , 2009 .

[13]  N. P. Andrianopoulos,et al.  Displacements Measurement in Irregularly Bounded Plates Using Mesh Free Methods , 2006 .

[14]  H. Sol,et al.  Identification of Mechanical Material Behavior Through Inverse Modeling and DIC , 2008 .

[15]  Tomonari Furukawa,et al.  Towards the robotic characterization of the constitutive response of composite materials , 2008 .

[16]  J. Sevenhuijsen.  Two simple methods for deformation demonstration and measurement , 1981 .

[17]  John G. Michopoulos,et al.  Characterization of strain-induced damage in composites based on the dissipated energy density part I. Basic scheme and formulation , 1995 .

[18]  S. Timoshenko,et al.  Theory of Elasticity (3rd ed.) , 1970 .

[19]  S. Timoshenko,et al.  Theory of elasticity , 1975 .

[20]  Hugh Alan Bruck,et al.  Digital image correlation using Newton-Raphson method of partial differential correction , 1989 .

[21]  James S. Sirkis,et al.  System response to automated grid methods , 1990 .

[22]  M. Sutton,et al.  Full-field speckle pattern image correlation with B-Spline deformation function , 2002 .

[23]  M. Sutton,et al.  Systematic errors in digital image correlation due to undermatched subset shape functions , 2002 .

[24]  W. Peters,et al.  Digital Imaging Techniques In Experimental Stress Analysis , 1982 .

[25]  N. P. Andrianopoulos,et al.  Full‐Field Displacement Measurement of a Speckle Grid by using a Mesh‐Free Deformation Function , 2006 .