Print Email Facebook Twitter Accuracy of strain measurement systems on a non-isotropic material and its uncertainty on finite element analysis Title Accuracy of strain measurement systems on a non-isotropic material and its uncertainty on finite element analysis Author Baldassarre, Alessandro (Clarkson University) Ocampo, Juan (St. Mary’s University) Martinez, Marcias (Clarkson University) Rans, C.D. (TU Delft Structural Integrity & Composites) Date 2020 Abstract The application of strain gauges as recommended by the ASTM standards provides accurate strain measurements in isotropic materials. However, their use in composite materials becomes more challenging due to their anisotropic nature. In this study, we hypothesized that the use of the distributed sensing system and the three-dimensional digital image correlation, which can average strain along a line and surface, respectively, may account for strain variability in composite materials. This study shows an investigation on the mechanical properties of unidirectional, cross-ply, and angle-ply carbon-epoxy specimens using strain gauges, distributed sensing system, and digital image correlation. The Bhattacharyya distance method was used to provide a preliminary evaluation of the closeness of the three different measurement techniques while the B-basis statistical method was used to analyze the experimental data in order to obtain a more conservative and reliable material parameter compared to the conventional averaged value, recommended by ASTM standards. Finally, a finite element model was created in Ansys Workbench™ as a means of evaluating the implication of a single point strain gauges measurement, versus a line or a surface strain measurement. The finite element analysis investigation was performed at a laminae level using the measured experimental elastic modulus and at a lamina–lamina level in which the elastic modulus of the unidirectional case was used as input in all the laminate configurations. The former analysis showed good agreement between the finite element analysis and all the strain measurement systems with an averaged percentage difference below 5%. The latter analysis showed a higher discrepancy in the measured percentage difference. A comparison between the finite element analysis and the strain gauges measurements showed an overall percentage difference between the range of 10% and 26%. Distributed sensing system and three-dimensional digital image correlation measurements provided an overall percentage difference below 10% for all the specimen configurations with a maximum percentage difference recorded for the longitudinal angle-ply case of approximately 9%. Subject B-basiscarbon fiber reinforced polymer compositedigital image correlationdistributed sensing systemfinite element analysisstatistical methodsstrain gaugesStrains monitoring To reference this document use: http://resolver.tudelft.nl/uuid:3d7dab78-e7d6-4d78-9e27-17dd200a8233 DOI https://doi.org/10.1177/0309324720924580 ISSN 0309-3247 Source Journal of Strain Analysis for Engineering Design, 56 (2), 76-95 Part of collection Institutional Repository Document type journal article Rights © 2020 Alessandro Baldassarre, Juan Ocampo, Marcias Martinez, C.D. Rans Files PDF Accuracy_of_Strain_Measur ... alysis.pdf 2.73 MB Close viewer /islandora/object/uuid:3d7dab78-e7d6-4d78-9e27-17dd200a8233/datastream/OBJ/view