This deviation is due to the vertical spatial variation of the mechanical properties of wood within the stem. However, all stiffness parameters identified were systematically underestimated by approximately 30% in comparison to reference values. This improvement results from a more balanced influence of all stiffness parameters on the response of the 45° specimen. Better identification is obtained for the 45° configuration, for which only the parameter Q12 exhibits large scatter. For the 0° configuration, only the parameters Q 11 and Q66 are correctly identified, with coefficients of variation of the same order of magnitude as those obtained from reference tensile and shear tests. Two configurations are investigated: (1) with grain aligned along the specimen length (0° configuration) and (2) with grain at 45°. The displacement field over the gauge surface of the specimen is measured by the grid method. The approach relies on application of the virtual field method (VFM) to a rectangular specimen loaded in the Iosipescu fixture. The importance of the present result is to determine the applicability of DIC measurement field based on image resolution.Įxperimental results obtained from maritime pine (Pinus pinaster Ait.) wood are presented for the characterisation of all LR=(1,2) orthotropic stiffness parameters of clear wood specimens by a single test. However, even though lower resolution image has higher relative error than high resolution image, the effect of resolution is not significant if displacement field tends to be more uniform (the ratio between minimum and maximum displacement in an area of interest is higher than 0.5). Higher image resolution reduced relative error significantly in case where the minimum displacement in the area of interest is much smaller than the maximum displacement (very low ratio or high nonuniformity of the displacement). It was observed that both type of input images produce the similar tendency on the effect of image resolution to the accuracy of the measurement. The evaluation was based on the input images of the algorithms, which were artificial and experimental images. The present work evaluates the accuracy of 2D-DIC algorithms in relation with image resolution and the effect of non-uniformity of the displacement. In many cases on experimental mechanics, displacement field in an area of interest is usually nonuniform, in which the ratio between minimum and maximum displacement in that area of interest is high. On the other side, measurement accuracy by using DIC is related with the displacement field.
However, it is expensive to produce a high resolution images and in many cases they are not necessary.
In a common sense, higher image resolution provides a better result than lower image resolution. How you play is up to you.The enhancement of the accuracy in a 2D-DIC can be related to the image resolution. Gameplay ranges from simple and relaxed, to challenging and frenetic, and everywhere in between.
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