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

Abstract

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.

On the feasibility of crack propagation tracking and full field strain imaging via a strain compatibility functional and the Direct Strain Imaging method

“…In order to simulate imaging sensor noise, the nodal locations are perturbed by random vectors sampled from an appropriate distribution [47]. It has been found that a good approximation of the noise distribution is that of Gaussian distribution [43,47]. 4.…”

“…The framework assumes a Probability Density Function (PDF) f N that describes the position vector w i of each of the nodes in the field [56,47]. The contribution of the errors of the various sources is propagated through the computational steps involved in the execution of the DSI analysis to the SSCF s y .…”

Inverse characterization of composite materials via surrogate modeling

“…Decades of advances in force, displacement, and strain measurement techniques in general, and full-field strain measurement techniques in particular, have enabled the collection of very rich data sets from mechanical tests [9][10][11][12][13][14][15][16][17][18][19]. Having acquired these data, an integrated approach that combines experimental with numerical methods to recover the elastic parameters is very prevalent.…”

Determination of anisotropic mechanical properties of G-10 composite via Direct Strain Imaging

“…The properties as calculated by the compression experiment data are presented in Eqn. (22), with deviations indicating 95% confidence: Using Eqn. (7) we calculated:…”

“…Such techniques are much more convenient than strain gauges or extensometers because of the vastly reduced system complexity and trivial specimen preparation methods. The DSI methodology operates by tracking the kinematic evolution of centroids of marks painted on the surface of each specimen [15][16][17][18][19][20][21][22][23][24][25][26][27][28] as a function of loading increments or frames. The strain calculation is performed directly on the strain tensor, as described in [25], and provides all three components of strain (horizontal, vertical and shear).…”