Crystal Plasticity Simulations of Haynes 230, an Analysis of Single Crystal and Polycrystalline Experiments

2016 ◽  
Vol 258 ◽  
pp. 294-297
Author(s):  
Pietro Giovanni Luccarelli ◽  
Stefano Foletti ◽  
Garrett Pataky ◽  
Huseyin Sehitoglu
Keyword(s):  
Single Crystal ◽  
Crystal Plasticity ◽  
Local Strain ◽  
Tensile Tests ◽  
Electron Back Scatter Diffraction ◽  
Image Correlation ◽  
Model Parameters ◽  
Haynes 230 ◽  
Scale Levels ◽  
Polycrystalline Model

The behavior of a Ni-based superalloy, Haynes 230, was investigated at macro and micro scale level by means of a Crystal Plasticity (CP) model implemented in an open source Finite Element code, Warp3D. Single Crystal and polycrystalline specimens have been experimentally characterized with Digital Image Correlation (DIC) to identify the local strain field evolution. The results of single crystal’s tensile tests were used to obtain an estimation of the constitutive model parameters. Then a polycrystalline model, reproducing a tensile test with loading/unloading steps, was created starting from the microstructural data obtained with EBSD (electron back-scatter diffraction), which allowed the identification of grains geometry and orientations. The polycrystalline simulations were used to verify the prediction of the CP model over the experiment. The results of this study show that the comparison between experiments and numerical analysis is in good agreement on both global and local scale levels.

scholarly journals Deformation and damage evolution of a full-scale adhesive joint between a steel bracket and a sandwich panel for naval application

2020 ◽  
pp. 095440622094712
Author(s):  
Pankaj R Jaiswal ◽  
R Iyer Kumar ◽  
M Saeedifar ◽  
MN Saleh ◽  
Geert Luyckx ◽  
...  
Keyword(s):  
Damage Evolution ◽  
Sandwich Panel ◽  
Deformation Behaviour ◽  
Local Strain ◽  
Tensile Tests ◽  
Full Scale ◽  
Image Correlation ◽  
Cohesive Failure ◽  
Local Strains ◽  
Damage Initiation

The increasing interest for the application of adhesive joints in naval superstructures motivates researchers to gain an in-depth understanding of the mechanical behaviour and failure mechanisms of these joints. This work reports on an experimental study of the deformation behaviour and damage evolution of a full-scale multi-material joint using different instrumentation techniques. Adhesively bonded joints of steel to sandwich panel components have been subjected to quasi-static tensile tests during which the global deformation of the joint and local strain distributions were monitored using digital image correlation (DIC). During one particular tensile test, fibre optic Bragg sensors (FBG) were also applied to the specimen’s surface at different locations in order to quantify the evolution of local strains. Additionally, acoustic emission (AE) sensors were installed in order to monitor damage initiation and evolution with increasing levels of imposed deformation. This test showcased adhesive failure at the interface of the steel adherend and the adhesive, while cohesive failure was observed within the adhesive and skin failure at the interface between adhesive and the composite skin of the sandwich panel. The post-mortem observed failures modes were compared to the acoustic events that originated during the test due to damage initiation and propagation within the joint. The evolution of the different sensor signals, i.e. the damage expressed as cumulative AE energy and local strains measured with Bragg sensors and DIC, are mutually compared and acceptable correlation is found.

scholarly journals Studying the Damage Evolution and the Micro-Mechanical Response of X8CrMnNi16-6-6 TRIP Steel Matrix and 10% Zirconia Particle Composite Using a Calibrated Physics and Crystal-Plasticity-Based Numerical Simulation Model

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 759
Author(s):  
Faisal Qayyum ◽  
Sergey Guk ◽  
Ulrich Prahl
Keyword(s):  
Simulation Model ◽  
Crystal Plasticity ◽  
Mechanical Response ◽  
Tensile Load ◽  
Local Strain ◽  
Tensile Tests ◽  
Local Deformation ◽  
Zirconia Particle ◽  
Steel Matrix ◽  
Damage Criterion

The mechanical behavior of newly developed composite materials is dependent on several underlying microstructural phenomena. In this research, a periodic 2D geometry of cast X8CrMnNi16-6-6 steel and 10% zirconia composite is virtually constructed by adopting microstructural attributes from literature. A physics-based crystal plasticity model with ductile damage criterion is used for defining the austenitic steel matrix. The zirconia particles are assigned elastic material model with brittle damage criterion. Monotonic quasi-static tensile load is applied up to 17% of total strain. The simulation results are analyzed to extract the global and local deformation, transformation, and damage behavior of the material. The comprehensively constructed simulation model yields the interdependence of the underlaying microstructural deformation phenomena. The local results are further analyzed based on the interlocked and free regions to establish the influence of zirconia particles on micro-mechanical deformation and damage in the metastable austenite matrix. The trends and patterns of local strain and damage predicted by the simulation model results match the previously carried out in-situ tensile tests on similar materials.

Local Strain Imaging during Mechanical Loading of Lamellar Microstructures in Titanium Based Alloys

2004 ◽  
Vol 1-2 ◽  
pp. 159-164
Author(s):  
L. Babout ◽  
J. Quinta Da Fonseca ◽  
Michael Preuss
Keyword(s):  
Tensile Testing ◽  
Lamellar Microstructure ◽  
Local Strain ◽  
Boundary Region ◽  
Electron Back Scatter Diffraction ◽  
Surface Strain ◽  
Image Correlation ◽  
Fully Lamellar ◽  
Optical Micrographs

In this work optical microscopy in situ tensile testing has been carried out to study the localisation of surface strain in fully lamellar titanium alloys. The localised strain was measured by analysing the recorded optical micrographs using image correlation, and the orientation of the a lamellae colony was determined by using Electron Back Scatter Diffraction (EBSD). The results show a localisation of strain, which seems to depend on the crystallographic orientation of the a lamellae colony in the lamellar microstructure. No significant strain was observed in the former b grain boundary region.

scholarly journals Characterisation of the behaviour of welded aluminium structures under dynamic loading

2018 ◽  
Vol 183 ◽  
pp. 01038 ◽  
Author(s):  
Huon Bornstein ◽  
Brodie McDonald ◽  
Emily Frain ◽  
Daniel De Oliveira Damas ◽  
Eric Yang ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Time History ◽  
Base Plate ◽  
Tensile Tests ◽  
Weld Bead ◽  
Surface Strain ◽  
Image Correlation ◽  
Model Parameters ◽  
Strain Localisation ◽  
Force Time

The presence and quality of welds in metallic structures has the ability to influence their likelihood of failure under dynamic loading. This investigation focused on characterising the behaviour of a welded aluminium structure. Samples were taken from the parent metal, heat affected zone (HAZ) and the weld bead and high strain rate characterisation testing was performed to determine the Johnson-Cook (JC) strength and failure model parameters for each material. However, significant scatter was found in the data for the weld bead due to porosity within the samples. Additional tensile tests were performed using a rotating fly wheel machine with four larger samples, which were machined from the welded aluminium structure and contained HAZs on either side of the weld bead, located in the centre of the specimen. Three of the four samples had the weld bead ground flush to the level of the base plate. Digital image correlation was used to determine the surface strain within each region of the sample and identified significant strain localisation at the interface between the weld metal and the HAZ, as well as within the weld bead. Comparisons between the ground welded specimens and those with the weld reinforcement showed a different failure mode between the two specimens. For the ground specimens, the strain localisation in the weld bead initiated failure prior to the strain localisation occurring at the interface between the weld bead and HAZ. Sectioning of the welds indicated that the strain localisation in the weld bead may have been caused by significant levels of porosity within the weld bead. Preliminary numerical simulations of the ground specimens indicated that the force-time history could be well captured. However, as the strain localisation due to porosity is not captured using a JC model, in addition to the scatter in the characterisation data for the weld bead, failure was not accurately predicted numerically.

scholarly journals A Preisach Model for Monotonic Tension Response of Structural Mild Steel with Damage

2020 ◽  
Author(s):  
Petar Knežević ◽  
Dragoslav Šumarac ◽  
Zoran Perović ◽  
Ćemal Dolićanin ◽  
Zijah Burzić
Keyword(s):  
Mild Steel ◽  
Single Crystal ◽  
Tensile Tests ◽  
Engineering Practice ◽  
Preisach Model ◽  
Elastoplastic Behavior ◽  
Suitable Material ◽  
Tension Response ◽  
Axial Tensile ◽  
Polycrystalline Model

This paper presents the new type of Preisach model that describes the elastoplastic behavior of structural mild steel under axial monotonic tension load with damage. Newly developed model takes into account elastic region, horizontal yield plateau, plastic hardening region, and softening region due to material damage under tension. In order to study the monotonic behavior of structural mild steel and find suitable material properties for the model, monotonic axial tensile tests up to the failure are carried out. Tests are conducted on specimens of the three most common types of European structural steel S235, S275, and S355. The basis of the model represents a mathematical description of material single crystal monotonic axial behavior. In the multilinear mechanical model, a drop in stress, after achieving ultimate stress under tension is achieved by a negative stiffness element. The good agreement with experimental results is accomplished by parallel connection of infinitely many single crystal elements, forming the polycrystalline model. The model represents a good solution for common engineering practice due to its geometrical representation in form of Preisach triangle.

scholarly journals Localization of Plastic Deformation in Ti-6Al-4V Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1745
Author(s):  
Vladimir V. Skripnyak ◽  
Vladimir A. Skripnyak
Keyword(s):  
Testing Machine ◽  
Shear Bands ◽  
High Stress ◽  
Local Strain ◽  
Tensile Tests ◽  
Hydraulic Testing ◽  
Image Correlation ◽  
Strain Rates ◽  
Strain Fields ◽  
Gauge Section

This article investigated the mechanical behavior of Ti-6Al-4V alloy (VT6, an analog to Ti Grade 5) in the range of strain rates from 0.1 to 103 s−1. Tensile tests with various notch geometries were performed using the Instron VHS 40/50-20 servo hydraulic testing machine. The Digital Image Correlation (DIC) analysis was employed to investigate the local strain fields in the gauge section of the specimen. The Keyence VHX-600D digital microscope was used to characterize full-scale fracture surfaces in terms of fractal dimension. At high strain rates, the analysis of the local strain fields revealed the presence of stationary localized shear bands at the initial stages of strain hardening. The magnitude of plastic strain within the localization bands was significantly higher than those averaged over the gauge section. It was found that the ultimate strain to fracture in the zone of strain localization tended to increase with the strain rate. At the same time, the Ti-6Al-4V alloy demonstrated a tendency to embrittlement at high stress triaxialities.

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