scholarly journals Elastic-plastic fracture analysis of anisotropy effect on AA2050-T84 alloy at different temperatures: A Numerical Study

2021 ◽  
Vol 16 (59) ◽  
pp. 78-88
Author(s):  
Krishnaraja Kodancha ◽  
Nagaraj Ekabote ◽  
P P Revankar
Keyword(s):  
Cryogenic Temperature ◽  
Driving Forces ◽  
Numerical Study ◽  
Plastic Zone Size ◽  
Compact Tension ◽  
Constant Load ◽  
Plate Surface ◽  
Elastic Plastic ◽  
Compression Properties ◽  
Different Temperatures

The third generation Al-Li alloy AA2050-T84 is widely used in aircraft applications due to its lightweight and significant mechanical properties. The anisotropic variations of tensile and compression properties of this alloy at various temperatures are substantial. In this work, the variations of the J-integral, CTOD, and Plastic Zone Size (PZS) due to anisotropy of a 4-inch thick AA2050-T84 plate at ambient and cryogenic temperatures were studied numerically by using Compact Tension (C(T)) specimen. The material anisotropy resulted in fracture and constraint parameter variation for Mode-I constant load. Numerical results indicated a decrease in crack driving forces and a constraint parameter with the decrease in temperature at the plate surface and central location. Plate surface locations appear to be isotropic for both temperatures under elastic-plastic fracture analyses as crack driving forces were almost identical. The temperature effect is more on constraint as the normalized PZS values at ambient temperature have been twice that of cryogenic temperature. The isotropic behavior of a plate under sub-zero temperature makes the plate suitable for cryogenic temperature applications.

Numerical study on hydrogen permeation of ferritic steel evaluated under constant load

2016 ◽  
Vol 33 (2) ◽  
pp. 149-161 ◽  
Author(s):  
S. J. Kim ◽  
D. W. Yun ◽  
H. G. Jung ◽  
K. Y. Kim
Keyword(s):  
Ferritic Steel ◽  
Hydrogen Permeation ◽  
Numerical Study ◽  
Constant Load

Numerical Investigation of Ductile Fracture in Pipelines Under Complex Loading Using a Phenomenological Damage Model

2021 ◽  
Author(s):  
Iago S. Santos ◽  
Diego F. B. Sarzosa
Keyword(s):  
Ductile Fracture ◽  
Mechanical Response ◽  
Numerical Study ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Numerical Procedure ◽  
Complex Loading ◽  
Experimental Tests ◽  
Compact Tension ◽  
Axial Tensile

Abstract This paper presents a numerical study on pipes ductile fracture mechanical response using a phenomenological computational damage model. The damage is controlled by an initiation criterion dependent on the stress triaxiality and the Lode angle parameter, and a post-initiation damage law to eliminate each finite element from the mesh. Experimental tests were carried out to calibrate the elastoplastic response, damage parameters and validate the FEM models. The tested geometries were round bars having smooth and notched cross-section, flat notched specimens under axial tensile loads, and fracture toughness tests in deeply cracked bending specimens SE(B) and compact tension samples C(T). The calibrated numerical procedure was applied to execute a parametric study in pipes with circumferential surface cracks subjected to tensile and internal pressure loads simultaneously. The effects of the variation of geometric parameters and the load applications on the pipes strain capacity were investigated. The influence of longitudinal misalignment between adjacent pipes was also investigated.

scholarly journals Thermo elastic-plastic transition in a thin rotating disc with inclusion

2007 ◽  
Vol 11 (1) ◽  
pp. 103-118 ◽  
Author(s):  
Kumar Gupta ◽  
P Pankaj
Keyword(s):  
Thermal Effect ◽  
Internal Surface ◽  
Angular Speed ◽  
Incompressible Material ◽  
Plastic State ◽  
Percentage Increase ◽  
Compressible Material ◽  
Rotating Disc ◽  
Elastic Plastic ◽  
Different Temperatures

Stresses for the elastic-plastic transition and fully plastic state have been derived for a thin rotating disc with shaft at different temperatures and results have been discussed and depicted graphically. It has been observed that the rotating disc with inclusion and made of compressible material requires lesser angular speed to yield at the internal surface and higher percentage increase in angular speed to become fully plastic as compare to disc made of incompressible material. With the introduction of thermal effect the rotating disc with inclusion required lesser angular speed to yield at the internal surface. Rotating disc made of compressible material with inclusion requires higher percentage increase in angular speed to become fully-plastic as compare to disc made of incompressible material. Thermal effect also increases the values of radial and circumferential stresses at the internal surface for fully-plastic state. .

Experimental evaluation of fracture properties of bovine hip cortical bone using elastic–plastic fracture mechanics

2021 ◽  
pp. 1-10
Author(s):  
Waseem Ur Rahman ◽  
Rafiullah khan ◽  
Noor Rahman ◽  
Ziyad Awadh Alrowaili ◽  
Baseerat Bibi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Plastic Deformation ◽  
Fracture Mechanics ◽  
Cortical Bone ◽  
Elastic Deformation ◽  
Compact Tension ◽  
J Integral ◽  
Elastic Plastic ◽  
American Society ◽  
Fracture Specimens

BACKGROUND: Understanding the fracture mechanics of bone is very important in both the medical and bioengineering field. Bone is a hierarchical natural composite material of nanoscale collagen fibers and inorganic material. OBJECTIVE: This study investigates and presents the fracture toughness of bovine cortical bone by using elastic plastic fracture mechanics. METHODS: The J-integral was used as a parameter to calculate the energies utilized in both elastic deformation (Jel) and plastic deformation (Jpl) of the hipbone fracture. Twenty four different types of specimens, i.e. longitudinal compact tension (CT) specimens, transverse CT specimens, and also rectangular unnotched specimens for tension in longitudinal and transverse orientation, were cut from the bovine hip bone of the middle diaphysis. All CT specimens were prepared according to the American Society for Testing and Materials (ASTM) E1820 standard and were tested at room temperature. RESULTS: The results showed that the average total J-integral in transverse CT fracture specimens is 26% greater than that of longitudinal CT fracture specimens. For longitudinal-fractured and transverse-fractured cortical specimens, the energy used in the elastic deformation was found to be 2.8–3 times less than the energy used in the plastic deformation. CONCLUSION: The findings indicate that the overall fracture toughness measured using the J-integral is significantly higher than the toughness calculated by the stress intensity factor. Therefore, J-integral should be employ to compute the fracture toughness of cortical bone.

Numerical study of asymmetric and axisymmetric thermal jet with entropy generation concept

2021 ◽  
Vol 15 (1) ◽  
pp. 7628-7636
Author(s):  
D. Belakhal ◽  
Kouider Rahmani ◽  
Amel Elkaroui Elkaroui ◽  
Syrine Ben Haj Ayech ◽  
Nejla Mahjoub Saïd ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Numerical Study ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Variable Density ◽  
Current Investigation ◽  
Numerical Resolution ◽  
Different Temperatures ◽  
Density Ratios ◽  
The Impact

In the current investigation, numerical study of a thermal jet of asymmetric (rectangular and elliptical) and axisymmetric (circular) geometry was investigated with variable density to verify the impact of the ratio of density and geometry on the generation of entropy. The central jet was brought to different temperatures (194, 293 and 2110 K) to obtain density ratios (0.66, 1 and 7.2) identical to a mixture jet ((Air-CO2), (Air-Air) and (Air-He)), respectively. Solving the three-dimensional numerical resolution of the Navier Stocks for turbulent flow permanent enclosed on the turbulence model K-εstandard was made. The results acquired are compared with that carried out in previous experimental studies, where it was concluded that, the axisymmetric (circular) geometry increases the entropy generation.

Characterization of elastic-plastic corner deformation and stress fields

2019 ◽  
Vol 10 (5) ◽  
pp. 660-677
Author(s):  
Norwahida Yusoff ◽  
Feizal Yusof
Keyword(s):  
Three Dimensional ◽  
Correlation Method ◽  
Finite Geometry ◽  
Compact Tension ◽  
Image Correlation ◽  
Stress Fields ◽  
Element Analysis ◽  
Content Type ◽  
Elastic Plastic ◽  
Corner Vertex

Purpose The purpose of this paper is to present the characteristics of elastic-plastic deformation and stress fields at the intersection of a crack front and the free surface of a three-dimensional body, referred to as corner fields. Design/methodology/approach The structures of elastic-plastic corner deformation field were assessed experimentally by looking at the corner border displacement and strain fields on the surface of a compact tension (CT) specimen using digital image correlation method. For assessment and verification purposes, the results were compared with the fields predicted through finite element analysis. The latter method was used further to assess the corner stress field. Findings The characteristics of displacement, strain and stress fields in the vicinity of a corner vertex in a finite geometry CT specimen in a strain hardening condition are independent of load and geometry. One of the distinctive features that becomes evident in this study is that the stress state at the corner vertex at θ=0° is a simple uniaxial tension. Originality/value This paper provides some insights on the structure of elastic-plastic corner fields that could optimistically be served as a fundamental framework towards the development of analytical solutions for elastic-plastic corner fields.

Microscopy and microindentation mechanics of single crystal Fe−3 wt. % Si: Part I. Atomic force microscopy of a small indentation

1993 ◽  
Vol 8 (6) ◽  
pp. 1291-1299 ◽  
Author(s):  
S. Harvey ◽  
H. Huang ◽  
S. Venkataraman ◽  
W.W. Gerberich
Keyword(s):  
Plastic Zone ◽  
Single Crystal ◽  
Surface Displacement ◽  
Plastic Zone Size ◽  
Force Microscopy ◽  
Elastic Plastic ◽  
Atomic Force ◽  
Plastic Indentation ◽  
Volume Estimates ◽  
Small Indentation

Atomic force microscope measurements of elastic-plastic indentation into an Fe−3 wt. % Si single crystal showed that the volume displaced to the surface is nearly equal to the volume of the cavity. The surface displacement profiles and plastic zone size caused by a 69 nm penetration of a Vickers diamond tip are reasonably represented by an elastic-plastic continuum model. Invoking conservation of volume, estimates of the number of dislocations emanating from the free surface are reasonably consistent with the number of dislocations that have formed in the plastic zone to represent an average calculated plastic strain of 0.044.

Crack Growth Rates of Alloy 600 From the Davis-Besse Reactor CRDM Nozzle #3 in PWR Environment

2005 ◽  
Author(s):  
Omesh K. Chopra ◽  
Bogdan Alexandreanu ◽  
William J. Shack
Keyword(s):  
Crack Growth ◽  
Potential Drop ◽  
Compact Tension ◽  
Constant Load ◽  
Alloy 600 ◽  
Pressurized Water ◽  
Control Rod ◽  
Environmentally Assisted Cracking ◽  
Water Reactors ◽  
Nickel Base

Reactor–vessel internal components made of nickel–base alloys are susceptible to environmentally assisted cracking. A better understanding of the causes and mechanisms of this cracking may permit less conservative estimates of damage accumulation and requirements on inspection intervals of pressurized water reactors (PWRs). This paper presents crack growth rate (CGR) results for Alloy 600 removed from nozzle#3 of the Davis–Besse (D-B) control rod drive mechanism (CRDM). The tests were conducted on 1/4-T or 1/2-T compact tension specimens in simulated PWR environment, and crack extensions were determined by DC potential drop measurements. The experimental CGRs under cyclic and constant load are compared with the existing CGR data for Alloy 600 to determine the relative susceptibility of the D-B CRDM nozzle alloy to environmentally enhanced cracking. The CGRs under constant load for the nozzle material are higher than those predicted by the best-fit curve for Alloy 600 at 316 °C. The results also indicate significant enhancement of CGRs under cyclic loading in the PWR environment. Characterization of the material microstructure and tensile properties is described.

Numerical Study of a Plate with a Pre-Cracked Circular Notch

2014 ◽  
Vol 627 ◽  
pp. 101-104 ◽  
Author(s):  
Francesco Caputo ◽  
A. de Luca ◽  
Giuseppe Lamanna ◽  
Alessandro Soprano
Keyword(s):  
Fracture Mechanics ◽  
Plastic Zone ◽  
Numerical Study ◽  
Plastic Zone Size ◽  
Mode I ◽  
Zone Size ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Notch Edge ◽  
Circular Notch

In the recent years, the study of the behaviour of damaged structures has been focused on cracked components in presence of an extensive material yielding at the crack tip; under this condition, linear elastic fracture mechanics theory (LEFM) is not able to describe the real plastic zone shape and size. Within this work, an extensive numerical analysis, based on elastic plastic fracture mechanics theory (EPFM), of the plastic zone size at the tip of a Mode I pre-crack at the notch edge in a plate is presented.

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