Numerical Study of Mechanical Behaviour of Heterogeneous Materials

2012 ◽  
Vol 730-732 ◽  
pp. 549-554
Author(s):  
Rui M. Branco ◽  
Pedro Prates ◽  
Marta C. Oliveira ◽  
Nataliya A. Sakharova ◽  
J. Valdemar Fernandes
Keyword(s):  
Mechanical Behaviour ◽  
Numerical Study ◽  
Local Stress ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Correlation Technique ◽  
Element Analysis ◽  
Plastic Properties ◽  
The Difference

The mechanical behaviour of heterogeneous specimens under uniaxial tensile test is studied using finite element analysis. The difference between mechanical properties of adjacent regions in the heterogeneous specimen creates constraints which alter the strain path relatively to pure tension. A methodology for determining the local stress-strain curves is proposed and successfully tested numerically on the heterogeneous specimen composed by two materials with dissimilar plastic properties. This methodology has recourse to the same type of variables which are usually obtained experimentally with the digital image correlation technique.

Effect of specimen orientation to the rolling direction on uniaxial tensile forming and failure limits

2020 ◽  
Vol 234 (13) ◽  
pp. 1598-1603
Author(s):  
Puja Ghosal ◽  
Surajit Kumar Paul
Keyword(s):  
Sheet Metal ◽  
Ferritic Steel ◽  
Dual Phase Steel ◽  
Rolling Direction ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Correlation Technique ◽  
Dual Phase ◽  
Planar Anisotropy

Alteration of forming and failure limits due to planar anisotropy of the sheet metal significantly affects the safe forming operation region and finally successfully manufacturing of a sheet metal formed component. This article presents the effect of planar anisotropy on uniaxial tensile properties, forming and failure limits of cold-rolled ferritic and dual-phase steels. In-situ three dimensional digital image correlation technique is used to measure the evolution of local strain components during uniaxial tensile test. For both the steels, necking limit is highest for the specimen at an orientation of 90° to rolling direction, while failure limit is highest for those specimen whose orientation is 45° to rolling direction for ferritic steel, and both 0° and 90° to rolling direction for dual-phase steel. Uniaxial tensile deformation path for ferritic steel holds lower slope than dual-phase steel as depicted in major versus minor strain plot.

MECHANICAL CHARACTERIZATION OF NOTCHED HOT ROLLED MULTI-PHASE STEEL

2017 ◽  
Vol 41 (1) ◽  
pp. 39-50
Author(s):  
Ke Niu ◽  
Abdolhamid Akbarzadeh ◽  
Zengtao Chen
Keyword(s):  
Crack Formation ◽  
Sheet Steel ◽  
Rolling Direction ◽  
Experimental Studies ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Correlation Technique ◽  
Stretch Flanging ◽  
Hot Rolled

This paper presents a series of experimental and numerical studies on Hot Rolled Stretch Flanging steels. This study focuses on four prototyped Hot-Rolled Stretch Flanging steels (HR780SF). Circular- notched sheet steel samples are used to induce different stress triaxiality levels in the rolling direction of sheet materials. Digital image correlation technique measures the local true strain during the deformation process of the notched samples in uniaxial tensile test. The microstructure of the notched samples is examined to evaluate the effect of geometrical features of circular notches on the microstructural evolution during the plastic deformation. Finally, the numerical results obtained via a finite element simulation are validated by the collected experimental data. Our experimental studies reveal the possibility of crack formation along the width of HR780SF steels during the mechanical load. The crack formation, which deteriorates the structural performance of hot rolled steels, can be avoided by the heat treatment of samples prior to the mechanical tests. In addition, it is found that the effect of notch geometry on the stress state is much more considerable at the notch edge than the notch center.

Mechanical Behaviour of Alloy 800 Steam Generator Tube With a Circumferential Crack-Like Throughwall Flaw

2011 ◽  
Author(s):  
Congyue Wang ◽  
Xinjian Duan ◽  
Mukesh Jain
Keyword(s):  
Steam Generator ◽  
Mechanical Behaviour ◽  
Numerical Study ◽  
Strain Curve ◽  
Image Correlation ◽  
Element Analysis ◽  
Fea Model ◽  
Alloy 800 ◽  
Circumferential Crack ◽  
Tension Tests

This paper presents an experimental and numerical study of the mechanical behaviour of Alloy 800 tubes with a circumferential crack-like throughwall flaw. The crack-like throughwall flaw was simulated as a slot fabricated by Electron Discharge Machining (EDM). A digital image correlation (DIC) method is employed to measure the distribution of strain and the deformed EDM slot profile during the tension test. A Finite Element Analysis (FEA) model in ANSYS is then developed to predict the mechanical behaviour of Alloy 800 steam generator (SG) tubing in the tension tests. The FEA model with a verified material stress-strain curve and the calibrated failure criterion is applied to simulate the burst test of SG tubing with a circumferential crack-like throughwall flaw. The maximum allowable size for a circumferential throughwall crack is recommended based on FEA simulations.

scholarly journals Effect of PWHT on the Microstructure and Mechanical Properties of Friction Stir Welded DP780 Steel

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1097
Author(s):  
Umer Masood Chaudry ◽  
Seung-Chang Han ◽  
Fathia Alkelae ◽  
Tea-Sung Jun
Keyword(s):  
Mechanical Properties ◽  
Annealing Temperature ◽  
Tensile Elongation ◽  
Image Correlation ◽  
Frictional Heat ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Dp780 Steel

In the present study, the effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of friction stir welded (FSW) DP780 steel sheets was investigated. FSW was carried out at a constant tool rotation speed of 400 rpm and different welding speeds (200 mm/min and 400 min/min). A defect free weld was witnessed for both of the welding conditions. The mutual effect of severe plastic deformation and frictional heat generation by pin rotation during the FSW process resulted in grain refinement due to dynamic recrystallization in the stir zone (SZ) and thermo-mechanically affected zone (TMAZ). Lower tensile elongation and higher yield and ultimate tensile strengths were recorded for welded-samples as compared to the base material (BM) DP780 steel. The joints were subsequently annealed at various temperatures at 450–650 °C for 1 h. At higher annealing temperature, the work hardening rate of joints gradually decreased and subsequently failed in the softened heat-affected zone (HAZ) during the uniaxial tensile test. Reduction in yield strength and tensile strength was found in all PWHT conditions, though improvement in elongation was achieved by annealing at 550 °C. The digital image correlation analysis showed that an inhomogeneous strain distribution occurred in the FSWed samples, and the strain was particularly highly localized in the advancing side of interface zone. The nanoindentation measurements covering the FSWed joint were consistent with an increase of the annealing temperature. The various grains size in the BM, TMAZ, and SZ is the main factor monitoring the hardness distribution in these zones and the observed discrepancies in mechanical properties.

scholarly journals Coupled Thermomechanical Response Measurement of Deformation of Nickel-Based Superalloys Using Full-Field Digital Image Correlation and Infrared Thermography

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2163
Author(s):  
Krzysztof Żaba ◽  
Tomasz Trzepieciński ◽  
Sandra Puchlerska ◽  
Piotr Noga ◽  
Maciej Balcerzak
Keyword(s):  
Surface Temperature ◽  
Strain Rate ◽  
Rolling Direction ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Response Measurement ◽  
Sheet Rolling ◽  
Inconel Alloys ◽  
The Relationship

The paper is devoted to highlighting the potential application of the quantitative imaging technique through results associated with work hardening, strain rate and heat generated during elastic and plastic deformation. The aim of the research presented in this article is to determine the relationship between deformation in the uniaxial tensile test of samples made of 1-mm-thick nickel-based superalloys and their change in temperature during deformation. The relationship between yield stress and the Taylor–Quinney coefficient and their change with the strain rate were determined. The research material was 1-mm-thick sheets of three grades of Inconel alloys: 625 HX and 718. The Aramis (GOM GmbH, a company of the ZEISS Group) measurement system and high-sensitivity infrared thermal imaging camera were used for the tests. The uniaxial tensile tests were carried out at three different strain rates. A clear tendency to increase the sample temperature with an increase in the strain rate was observed. This conclusion applies to all materials and directions of sample cutting investigated with respect to the sheet-rolling direction. An almost linear correlation was found between the percent strain and the value of the maximum surface temperature of the specimens. The method used is helpful in assessing the extent of homogeneity of the strain and the material effort during its deformation based on the measurement of the surface temperature.

scholarly journals Mechanical Properties of a Typical Jurassic Shaximiao Sandstone Under Subzero and Deep in situ Temperature Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
R. He ◽  
L. He ◽  
B. Guan ◽  
C. M. Yuan ◽  
J. Xie ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crack Front ◽  
Image Correlation ◽  
Correlation Technique ◽  
Direct Tension ◽  
Reservoir Stimulation ◽  
The Difference ◽  
Lower Temperature ◽  
Highly Strained

Insight into the difference between the mechanical properties of rocks at low and in situ deep reservoir temperatures is vital for achieving a better understanding of fracking technologies with supercritical CO2 and liquid nitrogen. To address this issue, the fracking-related mechanical properties of the Shaximiao Formation sandstone (SS) were investigated through direct tension, uniaxial compression, and three-point bending fracture tests at a typical low temperature (Tlow) of −10°C and a reservoir temperature (Tin situ) of 70°C. The results showed that the tensile strength σt, compressive strength σc, and fracture toughness KIC of the SS were all higher at Tlow than at Tin situ, although to different extents. The KIC of the SS increased slightly more than σt at the lower temperature, while both σt and KIC of the SS increased significantly more than σc at the lower temperature. In addition to the strength, the stiffness (particularly the tensile stiffness) and the brittleness indices of SS were similarly higher at Tlow than at Tin situ. In situ monitoring using the digital image correlation technique revealed that a highly strained band (HSB) always appeared at the crack front. However, because of the inhomogeneous microstructure of the SS, the HSB did not always develop along the line connecting the notch tip to the loading point. This was a possible cause of the highly dispersed KIC values of the SS. The HSB at the crack front was notably narrower at Tlow than at Tin situ, suggesting that low temperatures suppress the plastic deformation of rocks and are therefore beneficial to reservoir stimulation.

Experimental-Numerical Assessment of Vintage Pipe and Girth Weld With a Geometrically Complex Corrosion Feature

2018 ◽  
Author(s):  
Stijn Hertelé ◽  
Timothy Galle ◽  
Koen Van Minnebruggen ◽  
Wim De Waele ◽  
Otto Jan Huising
Keyword(s):  
Tensile Test ◽  
Surface Profile ◽  
Image Correlation ◽  
Tensile Failure ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Fe Model ◽  
Axial Tensile ◽  
Simplifying Assumptions ◽  
Girth Welds

Standard pipe corrosion assessments are based on simplifying assumptions with respect to corrosion geometry and focus on pressure based loading. Moreover, when corrosion patches traverse girth welds, validity criteria to their assessment become impractically vague. The integrity of girth welds is additionally influenced by axial stresses, which may act in combination with hoop stress resulting from pressure. In an attempt to address these issues, the authors conducted a detailed assessment on a significant, highly irregular corrosion patch traversing a 12″ natural gas pipeline girth weld. The investigation comprises a full scale uniaxial tensile test and supporting detailed finite element (FE) analyses. Hereby, the model mesh adopts detailed geometrical characteristics resulting from a surface profile scan obtained from stereoscopic digital image correlation. The numerical model is validated based on the uniaxial tensile test, in the sense that plastic collapse and highly complex strain distributions are successfully reproduced. Finally, the FE model is used to explore axial tensile failure in presence of internal pressure.

The Test of Aircraft Material with Performance Parameters

2014 ◽  
Vol 540 ◽  
pp. 48-51
Author(s):  
Xia Ren ◽  
Lian Xiang Ma
Keyword(s):  
Large Scale ◽  
Plastic Material ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Performance Parameters ◽  
Analysis Software ◽  
Element Analysis ◽  
Aircraft Material ◽  
Yeoh Model ◽  
Experimental Data Analysis

This paper uses the ABAQUS finite element analysis software for modeling and nonlinear analysis of aircraft tires. Paper H44.5 × 16.5-21 aviation tires, The plastic material of the tire subjected to uniaxial stretching to obtain a rubber such as Young's modulus, Poisson's ratio of the material parameters. Uniaxial tensile test tests the tensile properties of the rubber, the use of large-scale numerical calculations and fitting analysis of the experimental data analysis software Matlab, Yeoh model mechanical parameters.

Studies on Post-Yield Behavior of Cortical Bone

2012 ◽  
Vol 232 ◽  
pp. 157-161 ◽  
Author(s):  
N.K. Sharma ◽  
J. Nayak ◽  
D.K. Sehgal ◽  
R.K. Pandey
Keyword(s):  
Plastic Deformation ◽  
Cortical Bone ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Yield Behavior ◽  
Plastic Properties ◽  
Joint Replacements ◽  
Hierarchical Assembly ◽  
Plastic Modulus ◽  
Stiffness Loss

Complex hierarchical assembly and presence of large amount of organics and water content are responsible for enough amount of plasticity in bone material. Plastic properties are not only important to assess the various changes and fracture risk in bone but also for the development of better bone implants and joint replacements. The present study is focused on the post-yield behavior of cortical bone. The plastic properties of goat femoral and tibiae cortical bone were assessed and compared in terms of plastic modulus (H), tangent modulus (Et), plastic work (Wp) and plastic strain (εp) using uniaxial tensile test. Both femoral and tibiae cortical bone were found to be having similar post-yield behavior and significant stiffness loss was observed in both the bones during plastic deformation. The value of plastic modulus for femoral cortical bone was found to be 1.2 times higher as compared to the corresponding value for tibiae cortical bone. This shows higher hardening rate for femoral cortical bone. It was also observed that femoral bone requires higher energy during plastic deformation until fracture as compared to tibiae cortical bone.

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