Identification of Material Parameters of PVC Foams using Digital Image Correlation and the Virtual Fields Method

This paper presents an effective methodology to characterize all the constitutive (elastic) parameters of an orthotropic polymeric foam material (Divinycell H100) in one single test using Digital Image Correlation (DIC) in combination with the Virtual Fields Method (VFM). A modified Arcan fixture is used to induce various loading conditions ranging from pure shear or axial loading in tension or compression to bidirectional loading. A numerical optimization study was performed with different loading angles of the Arcan test fixture and off-axis angles of the principal material axes. The objective is to identify the configuration that gives the minimum sensitivity to noise and missing data on the specimen edges, which are the two major issues when identifying the stiffness components from actual DIC measurements. Two optimized Arcan test configurations were chosen. The experimental results obtained for these two optimized test configurations show a significant improvement of the measurement accuracy compared with a pure shear load configuration. The larger sensitivity of the pure shear test to missing data as opposed to the tensile test is also evident from the experimental data and confirms the analysis from the optimization study. The recovery of missing data along the specimen edges is a promising way to further improve the identification results.

[1]  F. Pierron.  Identification of Poisson's ratios of standard and auxetic low-density polymeric foams from full-field measurements , 2010 .

[2]  Isaac M Daniel,et al.  Characterization of Anisotropic Polymeric Foam Under Static and Dynamic Loading , 2011 .

[3]  Andrea Poggialini,et al.  Elastic characterization of anisotropic materials by speckle interferometry , 2005 .

[4]  Ole Thybo Thomsen,et al.  Determination of mechanical properties of PVC foam using a modified Arcan fixture , 2012 .

[5]  Stéphane Avril,et al.  The Virtual Fields Method , 2012 .

[6]  S. Jeelani,et al.  Tensile and fracture behavior of polymer foams , 2006 .

[7]  François Hild,et al.  Identification of elastic parameters by displacement field measurement , 2002 .

[8]  Fabrice Pierron,et al.  The virtual fields method with piecewise virtual fields , 2006 .

[9]  Emmanuel E. Gdoutos,et al.  Multiaxial Characterization and Modeling of a PVC Cellular Foam , 2001 .

[10]  Ole Thybo Thomsen,et al.  Bidirectional Thermo-Mechanical Properties of Foam Core Materials Using DIC , 2011 .

[11]  Fabrice Pierron,et al.  On the use of simulated experiments in designing tests for material characterization from full-field measurements , 2012 .

[12]  Raphaël Moulart,et al.  Identification of the through-thickness rigidities of a thick laminated composite tube , 2006 .

[13]  Fabrice Pierron,et al.  Accurate comparative determination of the in-plane shear modulus of T300/914 by the iosipescu and 45° off-axis tests , 1994 .

[14]  W. F. Ranson,et al.  Applications of digital-image-correlation techniques to experimental mechanics , 1985 .

[15]  Stéphane Roux,et al.  Identification of damage fields using kinematic measurements , 2002 .

[16]  S. Jeelani,et al.  Static and Dynamic Characterization of Polymer Foams Under Shear Loads , 2004 .

[17]  R. K. Fruehmann,et al.  A Methodology for Obtaining Material Properties of Polymeric Foam at Elevated Temperatures , 2012 .

[18]  Yves Surrel,et al.  Moire and grid methods: a signal-processing approach , 1994, Other Conferences.

[19]  Michael R Wisnom,et al.  Identification of the Orthotropic Elastic Stiffnesses of Composites with the Virtual Fields Method: Sensitivity Study and Experimental Validation , 2007 .