Strain Field Measurements Using Digital Photogrammetry for Large Inflatable Structures

Strain measurements are an important tool to evaluate the safety and reliability of large inflatable structures. However, some problems exist when using known measurement techniques in engineering applications. In this work, a method based on digital photogrammetry (DP) and Delaunay triangulation is proposed to measure the strain fields. This method takes into consideration the complex surface profile and geometrical nonlinearity and is suitable for large inflatable structures for which strain fields can be obtained using only photogrammetry. The coordinates of the discrete points on inflatable structure are determined by digital photogrammetry, and then, these points are turned into a triangular mesh using the Delaunay triangulation method. The strains can finally be calculated using the finite element method (FEM) by using the changes in the coordinates. In this work, a bulge test for a circular fabric sheet is performed to verify the validity of the proposed method. The strain fields calculated from this method are compared with results from digital image correlation (DIC). Good agreement is found between the photogrammetry and DIC measurement results. The comparison indicates that the concept of using photogrammetry to measure a strain field is valid. Furthermore, the advantages and disadvantages of the proposed method are discussed.

[1]  Peng Jinsheng Nonlinear Finite Element Analysis of Reinforced Concrete Structures and Program Design , 2005 .

[2]  Hyoseong Lee,et al.  3-D measurement of structural vibration using digital close-range photogrammetry , 2013 .

[3]  R. Dutton,et al.  Delaunay triangulation and 3D adaptive mesh generation , 1997 .

[4]  Michael A. Sutton,et al.  The effect of out-of-plane motion on 2D and 3D digital image correlation measurements , 2008 .

[5]  Danny A. Barrows,et al.  Photogrammetric techniques for aerospace applications , 2012 .

[6]  Leyland G. Young,et al.  A Practical Approach for Scientific Balloon Film Strain Measurement using Photogrammetry , 2007 .

[7]  Dimitri Debruyne,et al.  Full-field optical deformation measurement in biomechanics: digital speckle pattern interferometry and 3D digital image correlation applied to bird beaks. , 2012, Journal of the mechanical behavior of biomedical materials.

[8]  Anand Asundi,et al.  Two-dimensional digital image correlation for in-plane displacement and strain measurement: a review , 2009 .

[9]  Catherine Avril Holt,et al.  An innovative tool to measure human skin strain distribution in vivo using motion capture and delaunay mesh , 2012 .

[10]  Thomas Luhmann,et al.  Close range photogrammetry for industrial applications , 2010 .

[11]  R. S. Pappa,et al.  Photogrammetry of a 5M inflatable space antenna with consumer-grade digital cameras , 2001 .

[12]  Jonathan T. Black,et al.  Dot-Projection Photogrammetry and Videogrammetry of Gossamer Space Structures , 2003 .

[13]  Stuart Robson,et al.  Practical testing of the precision and accuracy of target image centering algorithms , 1995, Other Conferences.

[14]  Du Xiao-yu,et al.  Accurate 3D Target Positioning in Close Range Photogrammetry with Implicit Image Correction , 2009 .

[15]  John Tyson,et al.  Full-field dynamic displacement and strain measurement—Specific examples using advanced 3D image correlation photogrammetry: Part II , 2003 .

[16]  Peter Avitabile,et al.  Photogrammetry and optical methods in structural dynamics – A review , 2017 .

[18]  J. Valença,et al.  Applications of photogrammetry to structural assessment , 2012, Experimental Techniques.

[19]  S. Evans,et al.  Measuring strain distributions in the tendon using confocal microscopy and finite elements , 2009 .

[20]  Joseph R. Blandino,et al.  Optical Strain Measurement of an Inflated Cylinder using Photogrammetry with Application to Scientific Balloons , 2004 .

[21]  Satoshi Nishiyama,et al.  Improved digital photogrammetry technique for crack monitoring , 2015, Adv. Eng. Informatics.

[22]  Richard S. Pappa,et al.  Photogrammetry Methodology for Gossamer Spacecraft Structures , 2002 .

[23]  John Tyson,et al.  Pull-field dynamic displacement and strain measurement using advanced 3D image correlation photogrammetry: Part 1 , 2003 .

[24]  Clive S. Fraser,et al.  Innovations in Automation for Vision Metrology Systems , 1997 .

[25]  Robert J. Renka,et al.  Algorithm 772: STRIPACK: Delaunay triangulation and Voronoi diagram on the surface of a sphere , 1997, TOMS.

[26]  Guillermo Garnica,et al.  Micro- and macro deformation measurement by extension of correlation technique , 2011 .

[27]  Jin Liang,et al.  Large field-of-view deformation measurement for transmission tower based on close-range photogrammetry , 2011 .

[28]  M. Ashrafi,et al.  High Strain Gradient Measurements in Notched Laminated Composite Panels by Digital Image Correlation , 2015 .

[29]  F. Yılmaztürk,et al.  Measurement of deflections in buried flexible pipes by close range digital photogrammetry , 2010 .

[30]  Masood Varshosaz,et al.  Displacement measurement of the soil nail walls by using close range photogrammetry and introduction of CPDA method , 2013 .

[31]  S. Naboulsi,et al.  Investigation of Geometric Imperfection in Inflatable Aerospace Structures , 2004 .

[32]  Hugh Alan Bruck,et al.  Quantitative Error Assessment in Pattern Matching: Effects of Intensity Pattern Noise, Interpolation, Strain and Image Contrast on Motion Measurements , 2009 .

[33]  Daniel Rixen,et al.  Feasibility of monitoring large wind turbines using photogrammetry , 2010 .