Measurement of tensile mechanical properties of fiber reinforced plastic rebars by 3D digital image correlation

2020 ◽  
Vol 62 (4) ◽  
pp. 422-428 ◽  
Author(s):  
Feipeng Zhu ◽  
Pengxiang Bai ◽  
Dong Lei
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
3D Digital Image Correlation ◽  
Reinforced Plastic

Measurement of tensile mechanical properties of fiber reinforced plastic rebars by 3D digital image correlation

2020 ◽  
Vol 62 (4) ◽  
pp. 422-428
Author(s):  
Feipeng Zhu ◽  
Pengxiang Bai ◽  
Dong Lei
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Curved Surfaces ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic

Abstract Fiber reinforced plastic (FRP) plays an increasingly important role in many engineering fields due to its advantages of light weight, low cost, simple maintenance, and excellent corrosion resistance. The conventional contact methods for deformation measurement, such as strain gauge and mechanical extensometer, have some shortcomings in measuring the strain of FRP rebar specimens with spiral curved surfaces. Therefore, the non-contact three-dimensional digital image correlation (3D-DIC) technique was employed to determine the tensile mechanical properties of two types of FRP rebar specimens, i. e. glass FRP (GFRP) and carbon FRP (CFRP) specimens. Uniaxial tensile tests with three different loading rates were conducted to obtain the stress-strain curves, elastic modulus, tensile strength and percentage total extension at maximum force of these two FRP specimens. Experimental results indicate that the axial-strain field of all FRP rebar specimens present nonuniform distribution and that the stress of GFRP and CFRP rebars varies linearly with the strain. Moreover, no yielding phenomenon was observed from the stress-strain curves, which indicates that both GFRP and CFRP rebars belong to the group of typical brittle materials. The dispersion of elastic moduli obtained using 3D-DIC is better than that using a clip-on extensometer, which demonstrates the validity of 3D-DIC for the determination of tensile mechanical properties of FRP rebars with spiral curved surfaces.

Application of 3D digital image correlation for the measurement of the tensile mechanical properties of high-strength steel

2021 ◽  
Vol 63 (4) ◽  
pp. 303-310
Author(s):  
Feipeng Zhu ◽  
Xiaoxia Gu ◽  
Pengxiang Bai ◽  
Dong Lei
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Digital Image Correlation ◽  
Yield Strength ◽  
Digital Image ◽  
High Strength Steel ◽  
High Strength ◽  
Experimental Results ◽  
Image Correlation ◽  
3D Digital Image Correlation

Abstract High-strength steel plays an important role in engineering fields such as infrastructure. For this reason, an accurate determination of its mechanical properties is of critical importance. Considering the inconvenience of conventional mechanical extensometers for the deformation measurement of small-scale specimens, 3D digital image correlation (3D-DIC) was used to measure the deformation of Grade 8.8 bolts and Q690 high-strength steel specimens by means of a uniaxial tensile test, and in this way, stress–strain curves, elastic modulus, yield strength, tensile strength, percentage elongation after fracture, and percentage reduction of area were obtained. Experimental results show that Grade 8.8 bolts and Q690 steel result in higher yield strength and tensile strength than common steel. Moreover, owing to the phenomenon that stress remains constant with strain increase in the yielding stage, the evolution process from elastic deformation to plastic deformation of the specimens during the yielding stage could be studied. Experimental results show that the axial strain of Grade 8.8 bolts increases from 0.3 to 1 % during the yielding stage and for Q690 specimens the corresponding strain increases from 0.4 to 1.8 %.

scholarly journals Damage assessment of a titanium skin adhesively bonded to carbon fiber–reinforced plastic omega stringers using acoustic emission

2021 ◽  
pp. 147592172110017
Author(s):  
Milad Saeedifar ◽  
Mohamed Nasr Saleh ◽  
Peter Nijhuis ◽  
Sofia Teixeira de Freitas ◽  
Dimitrios Zarouchas
Keyword(s):  
Acoustic Emission ◽  
Carbon Fiber ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Carbon Fiber Reinforced Plastic ◽  
Adhesively Bonded ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced

This study is devoted to the use of acoustic emission technique for a comprehensive damage assessment, that is, damage detection, localization, and classification, of an aeronautical metal-to-composite bonded panel. The structure comprised a titanium panel adhesively bonded to carbon fiber–reinforced plastic omega stringers. The panel contained a small initial artificial debonding between the titanium panel and one of the carbon fiber–reinforced plastic stringers. The panel was subjected to a cyclic increasing in-plane compression load, including loading, unloading, and then reloading to a higher load level, until the final fracture. The generated acoustic emission signals were captured by the acoustic emission sensors, and digital image correlation was also used to obtain the strain field on the surface of the panel during the test. The results showed that acoustic emission can accurately detect the damage onset, localize it, and also trace its evolution. The acoustic emission results not only were consistent with the digital image correlation results, but also managed to detect the damage initiation earlier than digital image correlation. Finally, the acoustic emission signals were clustered using particle swarm optimization method to identify the different damage mechanisms. The results of this study demonstrate the capability of acoustic emission for the comprehensive damage characterization of aeronautical bi-material adhesively bonded structures.

Application of Stress Analysis by Digital Image Correlation and Intelligent Hybrid Method to Unidirectional CFRP Laminate

2007 ◽  
Vol 345-346 ◽  
pp. 1121-1124 ◽  
Author(s):  
Kenji Machida ◽  
Mitsuru Sato ◽  
Shinji Ogihara
Keyword(s):  
Digital Image Correlation ◽  
Stress Analysis ◽  
Digital Image ◽  
Hybrid Method ◽  
Tensile Load ◽  
Correlation Method ◽  
Image Correlation ◽  
Fiber Reinforced ◽  
Cfrp Laminate ◽  
Reinforced Plastic

Fiber reinforced composites are heterogeneous and anisotropic. The applicability of the stress analysis methods on such heterogeneous and anisotropic materials is not well known. In the present study, an attempt is made to apply the digital image correlation method and the intelligent hybrid method to a carbon fiber reinforced plastic (CFRP) laminate. A material used is carbon/epoxy system. Laminate configuration is unidirectional. Tensile load is applied in off-axis (45 degrees) direction as well as longitudinal (0 degree) and transverse (90 degrees) directions on a CFRP laminate. Displacement, strain and stress fields due to the tensile loading in the CFRP unidirectional laminate are analyzed. The constitutive equation considering material anisotropy is built into the intelligent hybrid method used at the time of analyses. The validity of the algorithm is checked through comparison between results of the present method, experimental results from strain gauge method, and the analytical results from finite element method (FEM).

Error estimations of 3D digital image correlation measurements

2006 ◽  
Author(s):  
Thomas Becker ◽  
Karsten Splitthof ◽  
Thorsten Siebert ◽  
Peter Kletting
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
3D Digital Image Correlation ◽  
Error Estimations
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