scholarly journals A Study of Correlation between Crack Initiation during Dynamic Wear Process and Fatigue Crack Growth of Reinforced Rubber Materials

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Eric Euchler ◽  
Ondrej Kratina ◽  
Radek Stoček ◽  
Michael Gehde
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Wear Behavior ◽  
Wear Process ◽  
Rubber Blends ◽  
Truck Tires ◽  
Dynamic Wear ◽  
Dynamic Loading Conditions

The aim of this study is concentrated on the experimental investigation of crack initiation during dynamic wear process and its correlation with fatigue crack growth of reinforced rubber materials. The analyzed rubber compounds suitable for applications such as treads for truck tires were based on natural rubber (NR) and polybutadiene rubber (BR). The dynamic wear behavior has been studied using an own developed testing equipment based on gravimetric determination of mass loss of test specimen. Fatigue crack growth (FCG) analysis was performed under pulse loading in accordance with real dynamic loading conditions of rolling tires using the Tear Analyser (TA). We show the crack initiation process during dynamic wear with respect to different impact energies and correlate the liability of crack initiation with FCG data at given tearing energy as a function of the rubber compositions. We demonstrate the higher crack initiation resistance of rubber blends with increased content of BR, while a predominant influence of NR improves the resistance against crack propagation especially at higher strain levels due to strain induced crystallization.

Modeling of Fatigue Crack Propagation

2004 ◽  
Vol 126 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Yanyao Jiang ◽  
Miaolin Feng
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Fatigue Crack Propagation ◽  
Fatigue Crack Initiation ◽  
Cyclic Plasticity ◽  
R Ratio

Fatigue crack propagation was modeled by using the cyclic plasticity material properties and fatigue constants for crack initiation. The cyclic elastic-plastic stress-strain field near the crack tip was analyzed using the finite element method with the implementation of a robust cyclic plasticity theory. An incremental multiaxial fatigue criterion was employed to determine the fatigue damage. A straightforward method was developed to determine the fatigue crack growth rate. Crack propagation behavior of a material was obtained without any additional assumptions or fitting. Benchmark Mode I fatigue crack growth experiments were conducted using 1070 steel at room temperature. The approach developed was able to quantitatively capture all the important fatigue crack propagation behaviors including the overload and the R-ratio effects on crack propagation and threshold. The models provide a new perspective for the R-ratio effects. The results support the notion that the fatigue crack initiation and propagation behaviors are governed by the same fatigue damage mechanisms. Crack growth can be treated as a process of continuous crack nucleation.

scholarly journals Fatigue crack growth rate and crack initiation and fracture life under mixed modes I and II.

1986 ◽  
Vol 35 (395) ◽  
pp. 930-935 ◽  
Author(s):  
Toshimitsu YOKOBORI ◽  
Takeo YOKOBORI ◽  
Kenji ISHII ◽  
Kiyoshi SATO ◽  
Kazuo SHYOJI
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Mixed Modes

A Probabilistic Micromechanical Code for Predicting Fatigue Life Variability: Model Development and Application

2005 ◽  
Vol 128 (4) ◽  
pp. 889-895 ◽  
Author(s):  
K. S. Chan ◽  
M. P. Enright
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Model Development ◽  
Fatigue Crack Initiation ◽  
Crack Size ◽  
Crack Initiation Life ◽  
Variability Model

This paper summarizes the development of a probabilistic micromechanical code for treating fatigue life variability resulting from material variations. Dubbed MICROFAVA (micromechanical fatigue variability), the code is based on a set of physics-based fatigue models that predict fatigue crack initiation life, fatigue crack growth life, fatigue limit, fatigue crack growth threshold, crack size at initiation, and fracture toughness. Using microstructure information as material input, the code is capable of predicting the average behavior and the confidence limits of the crack initiation and crack growth lives of structural alloys under LCF or HCF loading. This paper presents a summary of the development of the code and highlights applications of the model to predicting the effects of microstructure on the fatigue crack growth response and life variability of the α+β Ti-alloy Ti-6Al-4V.

scholarly journals Machine Learning Based Prognostics of Fatigue Crack Growth in Notch Pre-cracked Aluminum 7075-T6 Rivet Hole

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Robert Haynes ◽  
Ghanashyam Joshi ◽  
Natasha Bradley
Keyword(s):  
Machine Learning ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Length ◽  
Crack Growth ◽  
Particle Filtering ◽  
Fatigue Crack Initiation ◽  
Length Measurements ◽  
Aluminum 7075

Constant stress amplitude fatigue tests were conducted on the notch pre-cracked Aluminum 7075-T6 rivet hole dog-bone coupons. Monitoring of visible surface crack length by special surface engraving using digital microscope images and by ultrasonic sensors signals was carried out to yield fatigue crack length measurements in relation to number of fatigue cycles applied. The experimental results provide ultrasonic sensor validation for fatigue crack length measurements. Fracto-graphic examination of failed fatigue surfaces has provided further confirmation of notch pre-crack length, crack initiation process, and crack growth marker bands. These experimental inputs were used in NASGRO and AFGROW software fatigue crack growth simulations. The simulation results did not match the crack initiation fatigue life measured by experiments. However, there was good agreement with crack growth simulations of larger cracks. Hence, we plan to develop a machine learning application that will learn the fatigue crack initiation and crack growth processes from data obtained from our own experiments and other fatigue data available from AFGROW databases. Nonlinear AutoRegressive models with eXogenous input (NARX) artificial neural network were used to predict crack growth longer than 5.0-mm. Particle filtering modeling with Bayesian updating was applied to these experimental data for prognostics of fatigue crack growth. A concept design and preliminary implementation results will be presented.

A French Guideline for Defect Assessment at Elevated Temperature and Leak Before Break Analysis

2003 ◽  
Author(s):  
Y. Kayser ◽  
S. Marie ◽  
M. H. Lacire ◽  
S. Chapuliot ◽  
B. Drubay
Keyword(s):  
Fatigue Crack ◽  
Elevated Temperature ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Characteristic Distance ◽  
Defect Assessment ◽  
Creep Fatigue ◽  
Creep Fatigue Crack ◽  
Leak Before Break

A large program is performed in France in order to develop, for the design and operating FBR plants, defect assessment procedures and Leak-Before-Break methods (L.B.B.). The main objective of this A16 guide is to propose analytical solutions at elevated temperature coherent with those proposed at low temperature by the RSE-M (RSE-M, 1997). The main items developed in this A16 guide for laboratory specimen, plates, pipes and elbows are the following: • Evaluation of ductile crack initiation and crack propagation based on the J parameter and material characteristics as JR-Δa curve or Ji / Gfr. Algorithms to evaluate the maximum endurable load under increasing load for through wall cracks or surface cracks are also proposed. • Determination of fatigue or creep-fatigue crack initiation based on the σd approach calculating stress and strain at a characteristic distance d from the crack tip. • Evaluation of fatigue crack growth based on da/dN-ΔKeff relationship with a ΔKeff derived from a simplified estimation of ΔJ for the cyclic load. • Evaluation of creep-fatigue crack growth adding the fatigue crack growth and the creep crack growth during the hold time derived from a simplified evaluation of C*. • Leak-Before-Break procedure. The fracture mechanic parameters determined in the A16 guide (KI, J, C*) are derived from handbooks and formula in accordance with those proposed in the RSE-M document for in service inspection. Those are: • The KI handbook for a large panel of surface and through-wall defects in plates, pipes and elbows. • Elastic stress and reference stress formula. • Analytical Js and Cs* formulations for mechanical and through thickness thermal load. The main part of the formula and assessment methodologies proposed in the A16 guide are included in a software, called MJSAM, developed under the MS Windows environment in support of the document. This allows a simple application of the analysis proposed in the document.

Fatigue Crack Initiation and Growth Behaviour of 316L Stainless Steel Manufactured Through Selective Laser Melting

2017 ◽  
Author(s):  
C. M. Davies ◽  
H. Thomlinson ◽  
P. A. Hooper
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
316L Stainless Steel ◽  
Fatigue Crack Initiation ◽  
Compact Tension ◽  
Growth Behaviour ◽  
Laser Melting

Selective Laser Melting (SLM) is a relatively new manufacturing technique that offers many benefits. However the utilisation of SLM manufactured components depends on the assurance of their integrity during operation. Tensile and high cycle fatigue tests have been performed on uniaxial samples manufactured using SLM of 316L stainless steel to examine the elastic-plastic deformation and fatigue crack initiation behaviour of the material. In addition, the fatigue crack growth behaviour has been determined from tests on compact tension samples manufactured using SLM. The influence of build orientation has been examined on the compact tension samples. The results are compared to values obtained from conventional manufacturing methods. The tensile samples have a higher strength but significantly lower ductility than wrought material. The fatigue strength of the SLM material was substantially less than wrought material, though a similar fatigue limit maybe seen, this may be attributed to porosity in the material. The fatigue crack growth rate of the SLM material was 5–10 times faster, for a given stress intensity factor, than wrought materials and strongly depended on crack orientation in relation to the build direction.

Effect of a large population of seeded alumina inclusions on crack initiation and small crack fatigue crack growth in Udimet 720 nickel-base disk superalloy

2021 ◽  
Vol 142 ◽  
pp. 105953
Author(s):  
J. Telesman ◽  
T.P. Gabb ◽  
P.T. Kantzos ◽  
P.J. Bonacuse ◽  
R.L. Barrie ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Large Population ◽  
Small Crack ◽  
Nickel Base ◽  
Udimet 720

Effect of Hydrogen Environment of Fatigue Crack Initiation and Fatigue Crack Growth from Small Holes in SUS304 Steel

2004 ◽  
Vol 2004.57 (0) ◽  
pp. 3-4
Author(s):  
Takahiro MATSUYAMA ◽  
Yasuji ODA ◽  
Hiroshi NOGUCHI ◽  
Kenji HIGASHIDA
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Initiation ◽  
Crack Growth ◽  
Fatigue Crack Initiation ◽  
Hydrogen Environment ◽  
Small Holes
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