Study on Lüders Deformation in Welded Mild Steel Using Infrared Thermography and Digital Image Correlation

2012 ◽  
Vol 585 ◽  
pp. 82-86 ◽  
Author(s):  
N. Srinivasan ◽  
N. Raghu ◽  
B. Venkatraman
Keyword(s):  
Digital Image Correlation ◽  
Mild Steel ◽  
Infrared Thermography ◽  
Digital Image ◽  
Tensile Testing ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing ◽  
Heterogeneous Deformation ◽  
Lüders Band

Studies on characterizing heterogeneous deformations in many materials under different loading conditions using imaging NDE techniques like Infrared thermography (IRT) and Digital image correlation (DIC) began in the last decade and have been reported by many researchers. This work aims in experimental investigation of one such heterogeneous deformation namely Lüders band phenomenon in welded IS 2062 E250-B mild steel during monotonic, uniaxial tensile testing using IRT and DIC. Also attempt has been made to study the generation of pre-yield microstrain in welded material. An understanding of nucleation and propagation of Lüders band in welded specimen is made based on temperature and strain changes.

scholarly journals Experimental and Numerical Investigations of Thin-Walled Stringer-Stiffened Panels Welded with RFSSW Technology under Uniaxial Compression

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1785 ◽  
Author(s):  
Andrzej Kubit ◽  
Tomasz Trzepiecinski ◽  
Łukasz Święch ◽  
Koen Faes ◽  
Jan Slota
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Testing Machine ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Stiffened Panels ◽  
Friction Stir ◽  
Uniaxial Tensile Testing ◽  
First Case ◽  
Thin Walled

Many aircraft structures are thin walled and stringer-stiffened, and therefore, prone to a loss of stability. This paper deals with accurate and validated stability analysis of the model of aircraft skin under compressive loading. Both experimental and numerical analyzes are conducted. Two different methods of joining panel elements are considered. In the first case, the panel is fabricated using rivets. In the second variant, the refill friction stir spot welding technique is used. Both types of panels are loaded in axial compression in a uniaxial tensile testing machine. The geometrically and physically nonlinear finite element analyzes of the panels were carried out in ABAQUS/Standard. The Digital Image Correlation measurement system ARAMIS has been utilized to monitor the buckling behavior and failure mode in the skin-stringer interface of the stiffened panels. The results of experiments and the digital image correlation system are presented and compared to the numerical simulations.

Initial research of changes in mechanical properties of polymer-graphene composite with use of Digital Image Correlation

2020 ◽  
Vol 24 (4) ◽  
pp. 19-30
Author(s):  
Anna Makuch ◽  
Grzegorz Mońka ◽  
Joanna Klimek ◽  
Konstanty Skalski
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Correlation Technique ◽  
Camera System ◽  
Graphene Composite ◽  
Uniaxial Tensile Testing ◽  
The Impact

The problem of the possibility of using digital image correlation to assess changes in the mechanical properties of a polymer composite with the addition of graphene (1% by weight) in the form of flakes was taken up in the paper. Samples for uniaxial tensile testing were produced by selective laser sintering from polyamide powder particles and multi-flake graphene. In the tests carried out using the three-camera system, a variable strain distribution was recorded in the heterogenic PA-G composite material. Maps developed in the evaluation process – in particular, tangential deformations – allowed to conclude the impact of axial load on PA-G behaviour in time in the area of the polymer matrix, graphene agglomerates, and their interfaces. The research showed that the digital image correlation technique is a perfect complement to traditional mechanical tests when determining the properties of new heterogeneous composites, in particular, polyamide-graphene composite. Real-time observation of changes in the material map allows for a detailed analyzes of complex micromechanical aspects.

Cross Weld Tensile Testing With Digital Image Correlation to Determine Local Strain Response

2021 ◽  
Author(s):  
William Siefert ◽  
James Rule ◽  
Boian Alexandrov ◽  
Jorge Penso ◽  
Michael P. Buehner
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Tensile Testing ◽  
Local Strain ◽  
Image Correlation ◽  
Strain Response

Local Constitutive Behavior of Undermatched Welded Joints in Pipeline Steel Using Digital Image Correlation Technology

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
X. Wu ◽  
J. Shuai ◽  
K. Xu ◽  
Z. Lv
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Welded Joints ◽  
Pipeline Steel ◽  
Image Correlation ◽  
Optical Observations ◽  
Uniaxial Tensile ◽  
Welded Steel ◽  
Steel Joint ◽  
Constitutive Parameters

Abstract Although the identification of local constitutive behaviors is possible based on digital image correlation (DIC), few studies have been reported that characterize the properties of the girth-welded joints of pipeline steel. The DIC technique was used to measure the strain fields of undermatched girth-welded joints of X80 pipeline steel under uniaxial tension in this paper. First, microstructure optical observations and micrometer hardness measurements were used to test the size and hardness of the subregions in the specimens. Second, the local strain data in different regions of the girth-welded joint were obtained via DIC technology, and the stress data were obtained via uniaxial tensile tests. Then, the stress–strain relationships of the weld metal (WM), base metal (BM), and subregions of the heat-affected zone (HAZ) of the girth-welded joints of pipeline steel were obtained. Finally, the constitutive parameters of the Ramberg–Osgood model in the different regions were determined by curve fitting of the strain and stress data. The local yield strength, elastic modulus, and hardening exponent of the welded joints were obtained. The yield stresses of the different subregions of the welded steel joint followed the sequence BM > WM > HAZ, which was consistent with the results of the hardness measurements. The hardening exponents of the different subregions of the welded steel joint followed the sequence HAZ > WM> BM.

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