Residual Fatigue Life Evaluation of the Engine Crank Shaft Based on the Cumulative Fatigue Damage Theory

2013 ◽  
Author(s):  
Liu Yumei ◽  
Yuan Wenhua
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Residual Fatigue Life ◽  
Life Evaluation ◽  
Fatigue Life Evaluation ◽  
Damage Theory ◽  
Cumulative Fatigue Damage ◽  
Residual Fatigue

Fatigue Life Evaluation of Pipe Welds in Power Plant Using Advanced Nondestructive Methods

2007 ◽  
Vol 26-28 ◽  
pp. 1251-1254
Author(s):  
Sang Guk Lee ◽  
Keun Bong Yoo ◽  
Sung Keun Park ◽  
Duck Gun Park
Keyword(s):  
Fatigue Life ◽  
Power Plant ◽  
Fatigue Damage ◽  
Pipeline Steel ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Life Evaluation ◽  
Fatigue Life Evaluation

The objective of this study is to estimate the feasibility of advanced nondestructive method(X-ray diffraction, AE(acoustic emission) and BN(barkhausen noise)measurement application for fatigue life evaluation of the high-temperature pipeline steel such as main steam pipe etc. in power plant. In this study, various nondestructive tests using various types of specimen simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages such as 1/4, 1/2 and 3/4 of fatigue life, respectively. As a result of X-ray diffraction tests for specimens simulated fatigue damages, we conformed that the variation of the full width at half maximum intensity decreased in proportion to the increase of fatigue life ratio. And also, AE and BN signal due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct expectation of the life consumption rate was feasible.

A Model for the Determination of Residual Fatigue Life of a Nickel-Based Superalloy

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Duyi Ye ◽  
Jinyang Zheng
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Strain Energy ◽  
Damage Mechanics ◽  
Residual Fatigue Life ◽  
Mechanics Model ◽  
Plastic Strain Energy ◽  
Residual Fatigue

In this paper, both the dissipation of the plastic-strain energy and the exhaustion of the static toughness during high-temperature low-cycle fatigue of GH4145/SQ superalloy were investigated. Together with the analysis of the microscopic aspects of the material, an energy-based damage mechanics model was developed for the prediction of the residual fatigue life of the high-temperature fastened parts in power plant. Experimental results show that the static toughness is a parameter that is highly sensitive to the fatigue damage process. The deterioration of the static toughness during fatigue process reveals the exhaustion of the materials’s ability to absorb energy, which is essentially associated with the irreversible energy dissipation process of the fatigue failure. Based on the dissipation of the plastic-strain energy and the exhaustion of the static toughness during fatigue, a damage variable is defined that is consistent with the fatigue damage mechanism. The variable is sensitive to the fatigue process and can be measured with a simple experimental procedure. A fatigue damage evolution equation is derived on the basis of Lemaitre’s potential of dissipation in the framework of continuum damage mechanics. Furthermore, an equation for the determination of the residual fatigue life is deduced. The fatigue damage mechanics model is verified by comparing the predicted results with the experimental observations. The fatigue damage mechanics model developed may provide a feasible approach to determining the residual fatigue life of the high-temperature fastened parts in power plant.

Fatigue Life Analysis of Turbine Disks Based on Load Spectra of Aero-engines

2016 ◽  
Vol 33 (1) ◽  
Author(s):  
Yan-Feng Li ◽  
Zhiqiang Lv ◽  
Wei Cai ◽  
Shun-Peng Zhu ◽  
Hong-Zhong Huang
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Load Spectra ◽  
Turbine Disks ◽  
Damage Theory ◽  
Fatigue Life Analysis ◽  
Cumulative Fatigue Damage ◽  
Aero Engines ◽  
Main Components ◽  
The Relationship

AbstractLoad spectra of aero-engines reflect the process of operating aircrafts as well as the changes of parameters of aircrafts. According to flight hours and speed cycle numbers of the aero-engines, the relationship between load spectra and the fatigue life of main components of the aero-engines is obtained. Based on distribution function and a generalized stress–strength interference model, the cumulative fatigue damage of aero-engines is then calculated. After applying the analysis of load spectra and the cumulative fatigue damage theory, the fatigue life of the first-stage turbine disks of the aero-engines is evaluated by using the

scholarly journals Experimental Study of the Influence on the Residual Fatigue Life of 45 # Steel Fatigue Damage Specimens

2013 ◽  
Vol 275-277 ◽  
pp. 220-224
Author(s):  
Ping Wang ◽  
Rong Yang ◽  
Ji Feng Tian
Keyword(s):  
Experimental Study ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
High Voltage ◽  
Voltage Pulse ◽  
Pulse Discharge ◽  
High Voltage Pulse ◽  
Residual Fatigue Life ◽  
Residual Fatigue

Abstract. In this paper, the fatigue life of the 45 # steel specimens is tested. Two groups of fatigue damage specimens are prepared for the experimental study. Their fatigue cycles respectively reached 80% and 90% of the fatigue life tested. The repairing experiments to the two groups’ specimens by the high voltage pulse discharge are finished. After these repairing experiments, the residual fatigue lives of the two group specimens repaired are tested. The results show that the residual fatigue lives of the specimens are improved greatly. The total fatigue lives of the specimens have been increased at least 160% of the fatigue life tested.

Fatigue Life Evaluation for Laser Cladding Component Based on Non-Linear Continuum Fatigue Damage Model

2015 ◽  
Vol 42 (9) ◽  
pp. 0903006
Author(s):  
华亮 Hua Liang ◽  
田威 Tian Wei ◽  
廖文和 Liao Wenhe ◽  
曾超 Zeng Chao
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Laser Cladding ◽  
Damage Model ◽  
Life Evaluation ◽  
Non Linear ◽  
Fatigue Life Evaluation

Fatigue Life Evaluation on the Seam Welds in the Main Rotation Platform of YTQH800

2012 ◽  
Vol 472-475 ◽  
pp. 1577-1581
Author(s):  
Ben Xue Liu ◽  
Hong Pu Yang ◽  
Xin Ke Xiao ◽  
Zhen Bo Yang
Keyword(s):  
Fatigue Life ◽  
Normal Stress ◽  
Fatigue Damage ◽  
Hot Spots ◽  
Dynamic Calculation ◽  
Transient Dynamic ◽  
Life Evaluation ◽  
Notch Stress ◽  
Dynamic Computation ◽  
Fatigue Life Evaluation

The fatigue life of the rotation platform of YTQH800 was evaluated based on transient dynamic calculation by using normal stress method in LMS VL. According to the evaluation, fatigue hot spots were predicted. A 3D sub-model with R=1 mm notches was built at one of the hot spots with the highest fatigue damage predicted previously. The stress history is obtained by transient dynamic computation. The detailed fatigue life was obtained by using notch stress method in LMS VL. The results provided technology supports to the structure optimum and improvement.

scholarly journals Assessment of residual fatigue life of metal beam of reinforced concrete superstructures of road bridges

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Elena Feoktistova
Keyword(s):  
Reinforced Concrete ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Steel Structures ◽  
Asymmetry Factor ◽  
Residual Fatigue Life ◽  
Fatigue Damage Accumulation ◽  
Residual Fatigue ◽  
Method Of Evaluation

The article proposes a method of evaluation of residual fatigue life of metal beam of reinforced concrete superstructures of road bridges. In the calculations of residual fatigue life were implemented statistical data of endurance characteristics of steel structures that mostly fully corresponds to the given junctions by design, material, production technology and force impact. Fatigue life is determined based on the hypothesis of linear addition of fatigue damage accumulation. The critical damage amount providing the target reliability considered equal to one. Residual fatigue life of metal beams is calculated based on endurance characteristics of different groups of welded joints.For the life period assessment the motor transport load including prospective is reduced to the estimated. The reduction factor is defined based on the stress level, asymmetry factor of stress cycle and steel grade according to the conditions of equality of fatigue damage accumulation. The method allows determining of the remaining fatigue life of welded metal beams according to the transport load. Service limit and usage mode are predicted based on the structural calculations taking into account defects and damages using actual size and considering manufacturing, constructing and operational defects. Moreover, changes of strength and fatigue characteristics should be taken into account. The method of evaluation of residual fatigue life of metal beam of reinforced concrete superstructures of road bridges proposed by the auther requires clarification of te current and future load impact. The fatigue life mostly depends on the performance of superstructures maintanance and repair works.

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