scholarly journals Fatigue damage and life evaluation of thick bi-material double strap joints for use in marine applications

2021 ◽  
Author(s):  
Rahul Iyer Kumar ◽  
Pankaj Jaiswal ◽  
Wim De Waele
Keyword(s):  
Digital Image Correlation ◽  
Experimental Tests ◽  
Fatigue Loading ◽  
Adhesive Joints ◽  
Image Correlation ◽  
Life Evaluation ◽  
Marine Applications ◽  
Extent Of Damage ◽  
Steel Joints ◽  
Cohesive Damage

The present-day interest in the use of composite-steel joints in primary marine applications requires an in-depth knowledge of the fatigue performance of thick adhesive joints. This paper reports on experimental tests, quasi-static and fatigue, performed on unaged and aged bi-material double strap joints with thick adhesive bondlines. The specimens are monitored by Digital Image Correlation and Infrared Thermography techniques to evaluate the types and extent of damage that occur in the joint during fatigue loading. The S-N curve of the aged joint is evaluated along with it’s fatigue limit. It is found that the unaged specimens fail due to cohesive damage, hackles and disbond at the adhesive-adherend interface and the aged specimens failed due to delamination within the composite. The specimens that survived fatigue loading showed similar residual strength as specimens that were not fatigue loaded.

scholarly journals Investigation by Digital Image Correlation of Mixed Mode I and II Fracture Behavior of Metallic IASCB Specimens with Additive Manufactured Crack-Like Notch

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 400 ◽  
Author(s):  
Ivo Campione ◽  
Tommaso Maria Brugo ◽  
Giangiacomo Minak ◽  
Jelena Janković Tomić ◽  
Nebojša Bogojević ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mixed Mode ◽  
Fracture Behavior ◽  
Selective Laser Sintering ◽  
Local Stress ◽  
Fatigue Loading ◽  
Image Correlation ◽  
Mode I ◽  
Displacement Fields

This work investigates the fracture behavior of maraging steel specimens manufactured by the selective laser sintering (SLS) technology, in which a crack-like notch (sharp notch) was directly produced during the additive manufacturing (AM) process. For the evaluation of the fracture toughness, the inclined asymmetrical semi-circular specimen subjected to three points loading (IASCB) was used, allowing to cover a wide variety of Mode I and II combinations. The effectiveness of manufacturing crack-like notches via the SLS technique in metals was evaluated by comparing the obtained experimental results with the ones obtained with pre-cracks induced by fatigue loading. The investigation was carried out by using the digital image correlation (DIC) technique, that allowed the evaluation of the full displacement fields around the crack tip. The displacement field was then used to compute the stress intensity factors (SIFs) for various combinations of Mode I and II, via a fitting technique which relies on the Williams’ model for the displacement. The SIFs obtained in this way were compared to the results obtained with the conventional critical load method. The results showed that the discrepancy between the two methods reduces by ranging from Mode I to Mode II loading condition. Finally, the experimental SIFs obtained by the two methods were described by the mixed mode local stress criterium.

scholarly journals Application of the 3D Digital Image Correlation to the Analysis of Deformation of Joints Welded With the FSW Method After Shot Peening

2019 ◽  
Vol 19 (4) ◽  
pp. 57-66
Author(s):  
A. Kubit ◽  
M. Bucior ◽  
R. Kluz ◽  
Ł. Święch ◽  
K. Ochał
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Shot Peening ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Image Correlation ◽  
X Ray Diffraction ◽  
Butt Joints ◽  
3D Digital Image Correlation ◽  
The Impact

AbstractThe three dimensional Digital Image Correlation (3D DIC) method is used for measurements of deformations and displacement in plane elements exposed to loading. The paper presents the experimental tests of an application of the ARAMIS system to the analysis of deformation of joints welded with the FSW method after shot peening treatment. The butt joints were made of 2024-T3 aluminum alloy sheets with the thickness of 1 mm, which next were peened with glass beads about granulation in range 500 ÷ 900 µm. Tests of residual stresses by X-ray diffraction were also carried out. The aim of the study was to analyze the impact of shot peening on the value of stresses and the location of deformations in butt joints.

scholarly journals Validation of Acoustic Emission (AE) Crack Detection in Aerospace Grade Steel Using Digital Image Correlation

2010 ◽  
Vol 24-25 ◽  
pp. 221-226 ◽  
Author(s):  
Rhys Pullin ◽  
Mark J. Eaton ◽  
James J. Hensman ◽  
Karen M. Holford ◽  
Keith Worden ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Digital Image Correlation ◽  
Crack Growth ◽  
Digital Image ◽  
Crack Detection ◽  
Peak Load ◽  
Fatigue Loading ◽  
Image Correlation ◽  
Crack Mouth Opening Displacement ◽  
Ae Signals

Acoustic Emission (AE) is a passive form of non-destructive testing that relies on the detection and analysis of stress waves released during crack propagation. AE techniques are successfully employed number of industries there remains some scepticism in aerospace engineering. The reported investigation details a single four point bend test specimen undergoing fatigue loading. This test is part of a much larger programme designed to demonstrate a technology readiness level (TRL) of five of the use of AE to detect crack initiation and growth in landing gear structures. The completed test required that crack growth had to be monitored to allow a comparison with the detected and located AE signals. The method of crack monitoring had to be non-contact so as not to produce frictional sources of AE in the crack region, preventing the use of crack mouth opening displacement gauges. Furthermore adhesives on the specimen surface had to be avoided to eliminate the possibility that the detected AE was from adhesive cracking, thus the use of strain gauges or foil crack gauges was not possible. A method using Digital Image Correlation (DIC) to monitor crack growth was investigated. The test was stopped during fatigue loading at 1000 cycle intervals and a DIC image captured at peak load. The displacement due to crack growth was observed throughout the investigation and the results compared with the detected AE signals. Results showed a clear correlation between AE and crack growth and added further evidence of TRL5 for detecting fractures in landing gears using AE.

scholarly journals Determination of the Shear Modulus of Pine Wood with the Arcan Test and Digital Image Correlation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 468
Author(s):  
Piotr Bilko ◽  
Aneta Skoratko ◽  
Andrzej Rutkiewicz ◽  
Leszek Małyszko
Keyword(s):  
Digital Image Correlation ◽  
Shear Modulus ◽  
Digital Image ◽  
Structural Model ◽  
Experimental Tests ◽  
Plane Stress State ◽  
Image Correlation ◽  
Finite Element Program ◽  
Full Field ◽  
Principal Axes

Arcan shear tests with digital image correlation were used to evaluate the shear modulus and shear stress–strain diagrams in the plane defined by two principal axes of the material orthotropy. Two different orientation of the grain direction as compared to the direction of the shear force in specimens were considered: perpendicular and parallel shear. Two different ways were used to obtain the elastic properties based on the digital image correlation (DIC) results from the full-field measurement and from the virtual strain gauges with the linear strains: perpendicular to each other and directed at the angle of π/4 to the shearing load. In addition, the own continuum structural model for the failure analysis in the experimental tests was used. Constitutive relationships of the model were established in the framework of the mathematical multi-surface elastoplasticity for the plane stress state. The numerical simulations done by the finite element program after implementation of the model demonstrated the failure mechanisms from the experimental tests.

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