Dynamic Severity Criterion for Designing Against High Cycle Fatigue

1978 ◽  
Vol 100 (1) ◽  
pp. 10-15 ◽  
Author(s):  
G. S. A. Shawki
Keyword(s):  
Cyclic Loading ◽  
Dynamic Load ◽  
Applied Load ◽  
High Cycle Fatigue ◽  
Material Behavior ◽  
Cycle Fatigue ◽  
Novel Approach ◽  
Maximum Utilization ◽  
Severity Criterion

A novel approach to the interpretation of material behavior under cyclic loading is presented. In this approach a nondimensional criterion, featuring the dynamic severity of applied load, is put forward with a view to the provision of simple though confident assessment of component performance under dynamic load. The fatigue diagram based on the proposed criterion displays significant merits over previous diagrams, the presented approach thus providing an effective tool for designing against high cycle fatigue with due consideration to maximum utilization of material.

High Cycle Fatigue Tests at High Temperature under Superheated Steam Conditions

2012 ◽  
Vol 538-541 ◽  
pp. 1630-1633
Author(s):  
Jan Džugan ◽  
Tomas Misek
Keyword(s):  
Cyclic Loading ◽  
Superheated Steam ◽  
High Cycle Fatigue ◽  
Turbine Blades ◽  
Testing Procedure ◽  
Fatigue Tests ◽  
Material Behavior ◽  
Cycle Fatigue ◽  
Service Conditions ◽  
Increasing Demand

Increasing demand for reliable design of all kinds of structures requires materials properties evaluated under the conditions as close to real service conditions as possible. Presently resolved project dealing with development of new turbine blades geometry requires better understanding of the material behavior under service conditions. Service conditions of turbine blades are cyclic loading at high temperatures under superheated steam conditions. There are not commercially available testing systems providing such functionality and the system allowing samples loading under considered conditions is to be proposed. The paper deals with development of the testing equipment and testing procedure for high cycle fatigue tests in superheated steam corrosive environment. The system allowing cyclic loading at temperatures up to 650°C under superheated steam conditions was successfully designed, assembled and tested on series of testing samples.

High-cycle and very-high-cycle fatigue behavior of a stainless steel for air-conditioning compressor valve plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xu Jia ◽  
Yang Ou Xiang ◽  
Hu Yuan Pei ◽  
Song Wei
Keyword(s):  
Stainless Steel ◽  
Cyclic Loading ◽  
Air Conditioning ◽  
High Cycle Fatigue ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Content Type ◽  
Very High Cycle Fatigue ◽  
Load Characteristics ◽  
Very High

PurposeThe investigations could guide the structural design and fatigue life prediction of air-conditioning compressor valve plates.Design/methodology/approachThe High-Cycle Fatigue (HCF) and Very-High-Cycle Fatigue (VHCF) behaviors of stainless steel used for air-conditioning compressor valve plates were investigated. Monotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure.FindingsThe crack initiation can be observed as the arc-shaped cracks at both sides of specimens and Y-shaped crack bifurcation in the specimens. Moreover, the middle section and the cracks at both ends are not connected to the surface of the specimen. The stress-life results of the materials under two directions (vertical and horizontal) were provided to examine the difference in fatigue strength.Originality/valueMonotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure. Based on the experimental data, the results indicate that specimens under cyclic loading conditions could demonstrate better mechanical performance than static loadings.

Very High Cycle Fatigue Testing under Spectrum Loading for Endurance Limit Structural Design

2020 ◽  
Vol 65 (1) ◽  
pp. 1-7
Author(s):  
David T. Rusk ◽  
Robert E. Taylor ◽  
Bruce A. Pregger ◽  
Luis J. Sanchez
Keyword(s):  
Fatigue Test ◽  
Test Data ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Crack Nucleation ◽  
Peak Stress ◽  
Material Behavior ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

A program has recently concluded that generated fatigue test data for the influence of a rotorcraft main rotor blade root bending spectrum (Helix) on the crack nucleation mechanisms in 7075-T651 aluminum. High-frequency tests were performed that generated spectrum fatigue failures out to nearly 109 cycles. Fractographic examination showed a distinct change in crack nucleation from slip initiated to inclusion-initiated cracking as the spectrum peak stress level was increased. Spectrum life predictions were made using three different baseline constant-amplitude S-N curves, one using a traditional rotorcraft original equipment manufacturer fitting methodology, one using the high-cycle fatigue (HCF) portion of a strainlife curve, and one that was fitted to S-N data with test lives out to 3×108 cycles. The spectrum life prediction using the S-N curve that properly modeled material behavior in the very high cycle fatigue regime provided a good correlation to the spectrum fatigue test data. Predictions using the other S-N curves were highly conservative.

Fatigue Characteristic of S355J2 Steel after Surface Frictional-Mechanical Treatment in Corrosive Environment

2014 ◽  
Vol 224 ◽  
pp. 21-26
Author(s):  
Dorota Kocańda ◽  
Andrzej Górka ◽  
Krzysztof Grzelak ◽  
Janusz Torzewski ◽  
Ellina Łunarska ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Mechanical Treatment ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Corrosive Environment ◽  
Cycle Fatigue ◽  
Constant Amplitude ◽  
Fatigue Characteristic ◽  
Low Alloyed Steel

In the paper low (LCF) and high cycle fatigue (HCF) behavior of the S355J2 low alloyed steel after surface frictional-mechanical treatment in a corrosive environment (3.5 % NaCl ) has been presented. The treatment was used in order to improve mechanical and fatigue properties of the steel. Obtained experimental results indicate an insignificant improvement of mechanical and fatigue properties of the strengthened steel under the conditions of corrosion at constant amplitude cyclic loading. It is particularly noticeable in the range of low-cycle fatigue.

Prediction of High Cycle Fatigue Property of Ti-6Al-4V Alloy Using Artificial Neural Network

2016 ◽  
Vol 849 ◽  
pp. 360-367
Author(s):  
Ye Man Zhao ◽  
Hong Chao Kou ◽  
Wei Wu ◽  
Ying Deng ◽  
Bin Tang ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Cyclic Loading ◽  
Bp Neural Network ◽  
High Cycle Fatigue ◽  
Volume Fraction ◽  
Fatigue Property ◽  
Loading Frequency ◽  
Cycle Fatigue ◽  
Artificial Neural

In this paper, the relationship between microstructure, parameters of cyclic loading and high cycle fatigue property of Ti-6Al-4V alloy was established by artificial neural network (ANN) modeling. The back propagation (BP) neural network and radial basis function (RBF) neural network were established by MATLAB. The input parameters of these models were the primary α volume fraction, primary α size, cyclic loading frequency and stress ratio. The output parameter was high cycle fatigue strength. The neural networks were trained with dataset collected from the literature. The prediction results showed that both of the networks have good generalization ability. In addition, the BP neural network with Levenberg-Merquardt (LM) learning algorithm has better fault tolerance and versatility in dealing with high cycle fatigue property, which is able to predict the high cycle fatigue property with a high accuracy.

Probabilistic Mesomechanics for High Cycle Fatigue Life Prediction

1999 ◽  
Vol 122 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Robert G. Tryon ◽  
Thomas A. Cruse
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
High Cycle Fatigue ◽  
Crack Nucleation ◽  
Fatigue Loading ◽  
Material Behavior ◽  
Analytical Models ◽  
Cycle Fatigue ◽  
Prediction Capability ◽  
Fast Fracture

This paper presents an analytical modeling approach to characterize and understand high cycle fatigue life in gas turbine alloys. It is recognized that the design of structures subjected to fatigue cannot be based on average material behavior but that designs must consider −3σ or some other appropriate extreme value (tail of the distribution) loading and/or material properties. Thus, a life prediction capability useful in a design application must address the scatter inherent in material response to fatigue loading. Further, the life prediction capability should identify the key micromechanical variables that are critical in the tail of the materials durability distribution. The proposed method addresses the scatter in fatigue by investigating the microstructural variables responsible for the scatter and developing analytical and semi-analytical models to quantitatively relate the variables to the response. The model is general and considers the entire range of damage accumulation sequences; from crack nucleation of the initially unflawed structure to final fast fracture. [S0094-4289(00)01302-5]

A Microscale Approach for Modelling Concrete Fatigue Damage-Mechanisms

2019 ◽  
Vol 827 ◽  
pp. 73-78
Author(s):  
Antonio Caggiano ◽  
Diego Said Schicchi ◽  
Sha Yang ◽  
Stefan Harenberg ◽  
Viktoria Malarics-Pfaff ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Cyclic Loading ◽  
High Cycle Fatigue ◽  
Cyclic Stress ◽  
Constitutive Law ◽  
Cycle Fatigue ◽  
Micro Scale ◽  
Plastic Damage ◽  
Cement Based Materials ◽  
Microscale Approach

A micro-scale-based approach for the numerical analysis of cement-based materials, subjected to low-and high-cycle fatigue actions, is presented in this paper. The constitutive model is aimed at describing the evolving microstructural changes caused by cyclic loading protocols. More specifically, statistically representative microscopic geometries are equipped with a fracture-based model combined with a continuous inelastic constitutive law accumulating damage induced by the cyclic stress. The plastic-damage-based model is formulated combining the concepts of fracture-energy theories and damage stiffness degradations, representing the key phenomena occurring in concrete under fatigue. The paper explores the potential of the technique for assessing fatigue microcracks formation and growth, and their influence on the macroscopic behavior.

HIGH-CYCLE FATIGUE BEHAVIOR OF AM3 NICKEL-BASE SINGLE CRYSTAL SUPERALLOY AT HIGH TEMPERATURE

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2886-2891 ◽  
Author(s):  
L. SHUI ◽  
T. JIN ◽  
X.F. SUN ◽  
Z.Q. HU
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Fatigue Strength ◽  
Cyclic Loading ◽  
Single Crystal ◽  
High Frequency ◽  
High Cycle Fatigue ◽  
Cyclic Stress ◽  
Cycle Fatigue ◽  
Nickel Base

A single crystal nickel-base superalloy with ‹001› orientation was subjected to high cycle fatigue loading at temperature of 700°C and 870°C. The tests were performed in ambient atmosphere under load control at a stress ratio R =σ min /σ max =0.1 and a frequency of 83.3 Hz on smooth specimens. In this paper, the premature initiation and rapid propagation of cracks to failure due to high frequency cyclic loading were explored. The dislocation characteristics and fracture surface observation were evaluated through scanning electron microscopy and transmission electron microscopy, respectively. The results showed that the fatigue strength at 700°C was higher than that at 870°C. At 700°C the interaction of cyclic stress with high temperature induced the precipitation of homogeneous hyperfine secondary γ′ particles, that is beneficial to fatigue strength. At 870°C, the cyclic stress led to the formation of persistent slip bands moving through the γ matrix channels and the γ′ precipitates. The morphology change of γ′ phase was not notable during the deformation at high frequency cyclic loading.

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