SENT Stable Tearing Crack Path Deviation and its Influence on J

2015 ◽  
Author(s):  
Emily K. Hutchison ◽  
Philippa L. Moore ◽  
Warren P. Bath
Keyword(s):  
Fracture Toughness ◽  
Crack Path ◽  
Initial Crack ◽  
Parent Material ◽  
Propagation Path ◽  
Crack Plane ◽  
Element Analysis ◽  
Edge Notch ◽  
Path Deviation ◽  
Stable Tearing

Crack path deviation in Single Edge Notch Tension (SENT) specimens, and its influence on the determination of J, has been investigated as part of the development of a new British Standard for SENT testing, BS 8571 [1]. Crack path deviation by angles up to 50° have been observed during stable tearing in parent material SENT specimens. This paper investigates the effect of crack path deviation on the measured fracture toughness, and offers a correction formula when crack path deviation invalidates the default standard J equations. Mixed mode effects in crack path deviation are also investigated. A parametric study using finite element analysis has been carried out to compare the value of J calculated using standard equations (which assume a straight crack propagation path) with the value of J calculated using the contour integral method for different levels of crack path deviation. Crack path deviation from the initial crack plane resulted in a non-conservative estimate of fracture toughness using the standard equations. This means that any SENT test exhibiting crack path deviation may need to be discarded, wasting valuable test specimens. Instead, a correction factor has been developed to adjust the calculated value of J if path deviation is observed.

Numerical Simulation and Analysis on Crack Path Deviation in Brittle Solid

2006 ◽  
Vol 324-325 ◽  
pp. 931-934 ◽  
Author(s):  
Tian Hui Ma ◽  
Chun An Tang ◽  
Tao Xu ◽  
Zheng Zhao Liang
Keyword(s):  
Fracture Surface ◽  
Fracture Resistance ◽  
Crack Path ◽  
Process Analysis ◽  
Failure Process ◽  
Initial Crack ◽  
Numerical Code ◽  
Model Parameters ◽  
Brittle Solid ◽  
Path Deviation

Ductile tearing of brittle solid with initial crack is studied numerically. This work is focused on the simulation and analysis of crack path deviation for the respective configuration and the study of relation between crack length and the fracture resistance, and that the configuration of fracture surface is also observed. The simulating tool is a novel numerical code, 3D Realistic Failure Process Analysis code (abbreviated as RFPA3D). The simulating investigation has shown that the fracture resistance decreases with the increase of the angle between the crack ends and horizontal direction. Due to heterogeneity of materials distribution, crack path deviation towards the softer zone or elements is observed. The topography of the non-planar fracture surface has plotted. Concluding the simulation made in the present study, the problem of crack extension in the brittle solid can be handled by RFPA3D. Fracture resistance can be predicted and the crack path deviation be simulated, if the model parameters have been carefully identified and the mesh design is adequate. So this work is beneficial to choose safe load-spots and predicate the direction of the crack path deviation.

Fracture toughness assessment at different regions in an inertial friction welded Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy plate

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yingping Ji ◽  
Sujun Wu
Keyword(s):  
Fracture Toughness ◽  
Crack Propagation ◽  
Parent Material ◽  
Propagation Path ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Alloy Plate ◽  
Temperature Fracture ◽  
The Individual ◽  
Crack Tip Opening

Abstract The study aims to ascertain the influences of position on fracture toughness and fracture mechanism of inertial friction welded Ti-5Al-2Sn-2Zr-4Mo-4Cr joints. The room-temperature fracture toughness values of the parent material and three other regions in the weld were evaluated by standard crack tip opening displacement tests. The micro-structure and tensile properties of the welds were also investigated. Based on the observation of fracture surface and crack propagation path, a schematic illustration of the crack propagation was formed. The results suggest that the weld metal had the worst fracture toughness. The individual fracture toughness of different regions in the weld could be explained by the various modes of crack propagation, which were affected by different microstructures.

Comparative Analysis of Fracture Toughness Obtained by Different Techniques in Alumina Matrix - Dispersed TZP Zirconia Composites

2016 ◽  
Vol 869 ◽  
pp. 46-51
Author(s):  
Daniel Alessander Nono ◽  
Eron Fernandes da Silva ◽  
Maria do Carmo de Andrade Nono ◽  
Francisco Piorino Neto ◽  
Sergio Luiz Mineiro
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Ceramic Composites ◽  
Alumina Matrix ◽  
Single Edge ◽  
Chemical Inertness ◽  
Edge Notch ◽  
Properties Of Materials ◽  
Experimental Values ◽  
Benefit Cost

The fracture toughness is one of the requirements for mechanical properties of materials for use in satellites. The ceramic TZP zirconia (tetragonal zirconia polycrystals) have been investigated for applications in ballistic armor. Due to the chemical inertness and fracture toughness, this material has the potential to act as a screen against impacts of micrometeorites and space debris. The ceramic composites of alumina-zirconia 3Y-TZP (tetragonal zirconia polycrystals doped with 3 mol% ytria ) are the materials with the best benefit / cost for this application. This paper presents and discusses the results obtained from the use of two techniques for determining fracture toughness. The composite alumina - 18.5% of 3Y-TZP zirconia nanoparticles obtained from deflocculated powders have been tested for Vickers and the SEVNB penetration method (Single-Edge-Notch Beam V) to obtain the fracture toughness values (KIC). The KIC values obtained were analyzed due to the lower dispersion of experimental values. The SEVNB method showed better reliability in determining the toughness values in the studied ceramics.

Finite Element Analysis of the Hydro-Mechanical Punching Process

2006 ◽  
Vol 505-507 ◽  
pp. 871-876
Author(s):  
Jong Hun Yoon ◽  
Hoon Huh ◽  
Yong Sin Lee ◽  
Seung Soo Kim ◽  
E.J. Kim ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Ductile Fracture ◽  
Sheet Material ◽  
Middle Surface ◽  
Initial Crack ◽  
Fracture Criteria ◽  
Element Analysis ◽  
Final Fracture ◽  
Ductile Fracture Criteria ◽  
Punching Process

This paper investigates the characteristics of a hydro-mechanical punching process. The hydro-mechanical punching process is divided into two stages: the first stage is the mechanical half piercing in which an upper punch goes down before the initial crack is occurred; the second stage is the hydro punching in which a lower punch goes up until the final fracture is occurred. Ductile fracture criteria such as the Cockcroft et al., Brozzo et al. and Oyane et al. are adopted to predict the fracture of a sheet material. The index value of ductile fracture criteria is calculated with a user material subroutine, VUMAT in the ABAQUS Explicit. The hydrostatic pressure retards the initiation of a crack in the upper region of the blank and induces another crack in the lower region of the blank during the punching process. The final fracture zone is placed at the middle surface of the blank to the thickness direction. The result demonstrates that the hydro-mechanical punching process makes a finer shearing surface than the conventional one as hydrostatic pressure increases.

The Effects of Warm Pre-Stressing of a Pre-Cracked Pressurised Thermal Shock Disk Specimen Under a LUCF Loading Cycle

2011 ◽  
Author(s):  
H. Teng ◽  
D. W. Beardsmore ◽  
J. K. Sharples ◽  
P. J. Budden
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Thermal Shock ◽  
Local Stress ◽  
Superposition Method ◽  
Element Analysis ◽  
Loading Cycle ◽  
Finite Element Software ◽  
Disk Specimen ◽  
Apparent Fracture Toughness

A finite element analysis has been performed to investigate the effects of warm prestressing of a pre-cracked PTS-D (Pressurized Thermal Shock Disk) specimen, for comparison with the experimental work conducted by the Belgium SCK-CEN organisation under the European NESC VII project. The specimen was loaded to a maximum loading at −50 °C, unloaded at the same temperature, cooled down to −150 °C, and then re-loaded to fracture at −150 °C. This is a loading cycle known as a LUCF cycle. The temperature-dependant tensile stress-strain data was used in the model and the finite element software ABAQUS was used in the analysis. The finite element results were used to derive the apparent fracture toughness by three different methods: (1) Chell’s displacement superposition method; (2) the local stress matching method; and (3) Wallin’s empirical formula. The apparent fracture toughness values were derived at the deepest point of the semi-elliptical crack for a 5% un-prestressed fracture toughness of 43.96 MPam1/2 at −150 °C. The detailed results were presented in the paper.

Double Cantilever Beam Measurement and Finite Element Analysis of Cryogenic Mode I Interlaminar Fracture Toughness of Glass-Cloth/Epoxy Laminates

2000 ◽  
Vol 123 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Y. Shindo ◽  
K. Horiguchi ◽  
R. Wang ◽  
H. Kudo
Keyword(s):  
Fracture Toughness ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Cantilever Beam ◽  
Double Cantilever Beam ◽  
Mode I ◽  
Interlaminar Fracture Toughness ◽  
Element Analysis ◽  
Interlaminar Fracture ◽  
Delamination Crack

An experimental and analytical investigation in cryogenic Mode I interlaminar fracture behavior and toughness of SL-E woven glass-epoxy laminates was conducted. Double cantilever beam (DCB) tests were performed at room temperature (R.T.), liquid nitrogen temperature (77 K), and liquid helium temperature (4 K) to evaluate the effect of temperature and geometrical variations on the interlaminar fracture toughness. The fracture surfaces were examined by scanning electron microscopy to verify the fracture mechanisms. A finite element model was used to perform the delamination crack analysis. Critical load levels and the geometric and material properties of the test specimens were input data for the analysis which evaluated the Mode I energy release rate at the onset of delamination crack propagation. The results of the finite element analysis are utilized to supplement the experimental data.

Wide Range Compliance Solutions for Various Fracture Test Specimens Using Crack Mouth Opening Displacement

2017 ◽  
Author(s):  
Claudio Ruggieri ◽  
Rodolfo F. de Souza
Keyword(s):  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Width Ratio ◽  
Fracture Test ◽  
Single Edge ◽  
Opening Displacement ◽  
Element Analysis ◽  
Single Edge Notch ◽  
Wide Range ◽  
Edge Notch

This work addresses the development of wide range compliance solutions for tensile-loaded and bend specimens based on CMOD. The study covers selected standard and non-standard fracture test specimens, including the compact tension C(T) configuration, the single edge notch tension SE(T) specimen with fixed-grip loading (clamped ends) and the single edge notch bend SE(B) geometry with varying specimen spam over width ratio and loaded under 3-point and 4-point flexural configuration. Very detailed elastic finite element analysis in 2-D setting are conducted on fracture models with varying crack sizes to generate the evolution of load with displacement for those configurations from which the dependence of specimen compliance on crack length, specimen geometry and loading mode is determined. The extensive numerical analyses conducted here provide a larger set of solutions upon which more accurate experimental evaluations of crack size changes in fracture toughness and fatigue crack growth testing can be made.

Fracture Toughness Behaviour of 316L Stainless Steel Samples Manufactured Through Selective Laser Melting

2018 ◽  
Author(s):  
Catrin M. Davies ◽  
Ruijan Zhou ◽  
Olivia Withnell ◽  
Richard Williams ◽  
Tobias Ronneberg ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Compact Tension ◽  
Crack Plane ◽  
Laser Melting ◽  
Growth Plane ◽  
Toughness Testing ◽  
Tension Fracture

Selective laser melting (SLM) is a relatively new manufacturing technique which offers many benefits. However the utilisation of SLM manufactured components depends on the assurance of their integrity during operation. Fracture toughness testing (JIC) has been performed on as-built compact tension fracture mechanics samples manufactured in three orthogonal directions. When the crack growth plane was transverse to the interface of the build layers, the fracture toughness values were found to be similar to those manufactured using conventional techniques. However, the fracture toughness is significantly reduced when the crack plane is parallel to the interface of the build layers. Simple heat treatments have been performed on Charpy fracture samples and the resulting impact energy values indicate that the fracture toughness of a component may be improved by heat treatment.

Sign in / Sign up

Export Citation Format

Share Document