A multiresolution investigation on fatigue damage of aluminum alloys at micrometer level

2017 ◽  
Vol 26 (2) ◽  
pp. 192-209 ◽  
Author(s):  
H Chen ◽  
X Shi ◽  
Q He ◽  
JH Mao ◽  
Y Liu ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Thermal Loading ◽  
Low Cycle Fatigue ◽  
Transformation Process ◽  
Lessons Learned ◽  
Future Research ◽  
Element Analysis ◽  
Young’S Moduli ◽  
Macro Scale ◽  
Fatigue Damage Analysis

Fatigue damage is a form of material degradation under repeated mechanical and/or thermal loading. A new multiresolution fatigue damage analysis is formulated and used to estimate low-cycle fatigue damage. The progressive fatigue damage is measured based on the X-ray computed tomography. Then, the measured microcracks and microvoids are transformed to mesoscale and macro-scale damage variables. The entire transformation process is achieved analytically by means of 3D finite element analysis and specially formulated super representative volume elements. The estimated macro-scale damage variables in terms of effective Young’s moduli are compared with those measured experimentally and found to be in agreement. Some lessons learned in this study are provided for the direction of future research.

Visualization of Thermal Fatigue Damage Distribution With Elastic-Plastic FEA

2018 ◽  
Author(s):  
Junya Miura ◽  
Terutaka Fujioka ◽  
Yasuhiro Shindo
Keyword(s):  
Fatigue Damage ◽  
Thermal Fatigue ◽  
Thermal Loading ◽  
304 Stainless Steel ◽  
Element Analysis ◽  
Steel Cylinder ◽  
Elastic Plastic ◽  
Calculation Results ◽  
Type 304 ◽  
Cae System

This paper proposes simplified methods to evaluate fatigue damage in a component subjected to cyclic thermal loading, in order to visualize the distribution of usage factor using a graphical user interface (GUI) incorporated in a widely-used commercial CAE. The objective is to perform the evaluation and visualization using a standard desktop PC. In the previous paper, three simplified methods based on elastic finite-element analysis (FEA) were proposed in place of the method in the procedures employed in ASME Section III Subsection NH. In this paper, the methods have been improved for elastic-plastic FEA. A previously performed thermal fatigue test with a type 304 stainless steel cylinder was simulated. Heat transfer, elastic, and inelastic analyses were conducted. Simultaneously with the analyses performed, the equivalent total strain ranges and fatigue usage factor distributions were calculated using user subroutines developed in this study including three newly proposed simplified and ASME NH-based methods. These distributions can be visualized on a GUI incorporated in a commercial FEA code. The calculation results were consistent with the distribution of cracks observed. In addition, by using these, the analysts can visualize these distributions using their familiar CAE system.

Low Cycle Fatigue Analysis of after Treatment Device Induced due to Thermal Load by Using Finite Element Analysis

2014 ◽  
Vol 592-594 ◽  
pp. 1104-1108 ◽  
Author(s):  
Swapnil Vitthal Kumbhar ◽  
Vilas Kulkarni ◽  
R.M. Tayade
Keyword(s):  
Crack Initiation ◽  
Thermal Fatigue ◽  
Thermal Loading ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Analysis ◽  
Von Mises Stress ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Von Mises

Cyclic thermal loading causes cyclic thermal stress and thermal fatigue in the component. The goal of this paper is to characterize the thermal fatigue behavior of after-treatment (AT) device, i.e. Exhaust Gas Processor (EGP) and prediction of crack initiation cycles. The paper contains transient thermal analysis to map temperature on EGP model. By taking temperature distribution as input, Elasto-plastic structural analysis is done. Based on stress-strain data and fatigue material property, crack initiation cycles are estimated. For low cycle fatigue analysis, strain based approach, i.e. Brown-Miller Criteria with Morrow mean stress correction factor [1] is used. The von-Mises stress and crack initiation cycles are investigated and S-N curve and Ɛ-N curve are compared with standard graphs.

scholarly journals Fatigue Life Prognosis of a Light Aircraft Landing Gear Leg

2020 ◽  
Vol 12 (1) ◽  
pp. 9
Author(s):  
David Gerhardinger ◽  
Anita Domitrović ◽  
Ernest Bazijanac
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Computer Aided Design ◽  
Low Cycle Fatigue ◽  
Landing Gear ◽  
Load Spectrum ◽  
Design Environment ◽  
Element Analysis ◽  
Simple Method ◽  
Hard Time

Aircraft components are subject to fatigue damage. The prediction of fatigue life has significant influence on maintenance and flight operations. Light aircraft, designed for recreational purposes, have vital components that are subject to a hard time maintenance approach. The focus of this article is on a simple method for predicting fatigue life. The method is applied to a light aircraft’s fixed landing gear leg. The landing gear leg is modelled in a computer aided design environment. The load spectrum is determined, based on a characteristic flight profile. Principal strains are determined with finite element analysis. Fatigue life is calculated with the Coffin-Manson low cycle fatigue relation. The Palmgren-Miner rule is applied, and cumulative damage is determined. The results are compared to actual landing gear leg fatigue damage and the hard time replacement interval which is given in the corresponding maintenance manual.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

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