New Method for Concurrent Dynamic Analysis and Fatigue Damage Prognosis of Bridges

2012 ◽  
Vol 17 (3) ◽  
pp. 396-408 ◽  
Author(s):  
Jingjing He ◽  
Zizi Lu ◽  
Yongming Liu
Keyword(s):  
Dynamic Analysis ◽  
Fatigue Damage ◽  
New Method ◽  
Damage Prognosis

High Cycle Fatigue Damage Evaluation of Steel Pipelines Based on Microhardness Changes During Cyclic Loads: Part II

2018 ◽  
Author(s):  
Geovana Drumond ◽  
Bianca Pinheiro ◽  
Ilson Pasqualino ◽  
Francine Roudet ◽  
Didier Chicot
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
High Cycle Fatigue ◽  
Steel Structures ◽  
New Method ◽  
Microplastic Deformation ◽  
Surface Phenomenon ◽  
Cyclic Loads ◽  
Cycle Fatigue ◽  
Indentation Tests

The hardness of a material shows its ability to resist to microplastic deformation caused by indentation or penetration and is closely related to the plastic slip capacity of the material. Therefore, it could be significant to study the resistance to microplastic deformations based on microhardness changes on the surface, and the associated accumulation of fatigue damage. The present work is part of a research study being carried out with the aim of proposing a new method based on microstructural changes, represented by a fatigue damage indicator, to predict fatigue life of steel structures submitted to cyclic loads, before macroscopic cracking. Here, Berkovich indentation tests were carried out in the samples previously submitted to high cycle fatigue (HCF) tests. It was observed that the major changes in the microhardness values occurred at the surface of the material below 3 μm of indentation depth, and around 20% of the fatigue life of the material, proving that microcracking is a surface phenomenon. So, the results obtained for the surface of the specimen and at the beginning of the fatigue life of the material will be considered in the proposal of a new method to estimate the fatigue life of metal structures.

A New Method and Automatic Generation for Dynamic Analysis of Complex Planar Mechanisms Based on the Ordered Single-Opened-Chains

1994 ◽  
Author(s):  
Jian-Qing Zhang ◽  
Ting-Li Yang
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Equation ◽  
Automatic Generation ◽  
The Other ◽  
New Method ◽  
Complex Mechanism ◽  
Planar Mechanisms ◽  
Spatial Mechanisms ◽  
General Dynamic

Abstract This work presents a new method for kinetostatic analysis and dynamic analysis of complex planar mechanisms, i.e. the ordered single-opened-chains method. This method makes use of the ordered single-opened chains (in short, SOC,) along with the properties of SOC, and the network constraints relationship between SOC,. By this method, any planar complex mechanism can be automatically decomposed into a series of the ordered single-opened chains and the optimal structural decomposition route (s) can be automatically selected for dynamic analysis, the paper present the dynamic equation which can be used to solve both the kinetostatic problem and the general dynamic problem. The main advantage of the proposed approach is the possibility to reduce the number of equations to be solved simultaneously to the minimum, and its high automation as well. The other advantage is the simplification of the determination of the coefficients in the equations, and thus it maybe result in a much less time-consuming algorthem. The proposed approach is illustrated with three examples. The presented method can be easily extended to the dynamic analysis of spatial mechanisms.

A New Method for Dynamic Analysis of Mistuned Bladed Disks Based on the Exact Relationship Between Tuned and Mistuned Systems

2002 ◽  
Vol 124 (3) ◽  
pp. 586-597 ◽  
Author(s):  
E. P. Petrov ◽  
K. Y. Sanliturk ◽  
D. J. Ewins
Keyword(s):  
Dynamic Analysis ◽  
Frequency Response Function ◽  
New Method ◽  
Test Cases ◽  
Finite Element Models ◽  
Bladed Disks ◽  
Sector Model ◽  
Bladed Disk ◽  
Parametric Studies ◽  
Exact Relationship

A new method for the dynamic analysis of mistuned bladed disks is presented. The method is based on exact calculation of the response of a mistuned system using response levels for the tuned assembly together with a modification matrix constructed from the frequency response function (FRF) matrix of the tuned system and a matrix describing the mistuning. The main advantages of the method are its efficiency and accuracy, which allow the use of large finite element models of practical bladed disk assemblies in parametric studies of mistuning effects on vibration amplitudes. A new method of calculating the FRF matrix of the tuned system using a sector model is also developed so as to improve the efficiency of the method even further, making the proposed method a very attractive tool for mistuning studies. Various numerical aspects of the proposed method are addressed and its accuracy and efficiency are demonstrated using representative test cases.

Vehicle-induced fatigue damage prognosis of orthotropic steel decks of cable-stayed bridges

2020 ◽  
Vol 212 ◽  
pp. 110509
Author(s):  
Chuang Cui ◽  
You-Lin Xu ◽  
Qing-Hua Zhang ◽  
Feng-Yang Wang
Keyword(s):  
Fatigue Damage ◽  
Damage Prognosis ◽  
Orthotropic Steel Decks ◽  
Cable Stayed Bridges

Soft Impact Damage Prognosis of F-16 Canopy Using Progressive Failure Dynamic Analysis

2014 ◽  
Vol 51 (6) ◽  
pp. 1959-1965 ◽  
Author(s):  
Aaron J. Siddens ◽  
Javid Bayandor ◽  
Frank Abdi
Keyword(s):  
Dynamic Analysis ◽  
Impact Damage ◽  
Progressive Failure ◽  
Damage Prognosis

Dynamic Analysis on Flexible Cable-Driven Parallel Mechanism

2014 ◽  
Vol 1006-1007 ◽  
pp. 298-303
Author(s):  
Qing Lin Chen ◽  
Qi Lin
Keyword(s):  
Linear Programming ◽  
Dynamic Analysis ◽  
Parallel Mechanism ◽  
Sudden Change ◽  
Programming Method ◽  
New Method ◽  
Linear Programming Method ◽  
Flexible Cable

The interference between cables and surface of acutator limits the movement in the cable-driven parallel mechanism. The mechanism with fixed hinge can’t absolutely avoid the interference point of the track when using linear programming method. One new method, named as distant interference, was proposed to pick out all the interferential points of the track. Based on the principle of symmetrical force, the alteration to position of the six fixed hinges and two extensive hinges eliminated the interference. Through the simulation of combined spiral movement, the workspace of the flexible cable-driven parallel mechanism is larger than that of the mechanism with fixed hinge and reduce the interferece of long and big track. Compared with the original mechanism, the value of cables force in the flexible cable-driven parallel mechanism is smooth, continous and no sudden change.

Probabilistic fatigue damage prognosis using maximum entropy approach

2009 ◽  
Vol 23 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Xuefei Guan ◽  
Ratneshwar Jha ◽  
Yongming Liu
Keyword(s):  
Maximum Entropy ◽  
Fatigue Damage ◽  
Damage Prognosis

A multidisciplinary approach to structural health monitoring and damage prognosis of aerospace hotspots

2009 ◽  
Vol 113 (1150) ◽  
pp. 799-810 ◽  
Author(s):  
A. Chattopadhyay ◽  
P. Peralta ◽  
A. Papandreou-Suppappola ◽  
N. Kovvali
Keyword(s):  
Real Time ◽  
Fatigue Damage ◽  
Health Monitoring ◽  
Stochastic Modelling ◽  
Guided Wave ◽  
Model Complexity ◽  
Damage Classification ◽  
Element Analysis ◽  
Time Frequency ◽  
Damage Prognosis

Abstract The health monitoring and damage prognosis of aerospace hotspots is important for reducing maintenance costs and increasing in-service capacity of aging aircraft. One of the leading causes of structural failure in aerospace vehicles is fatigue damage. Based on the physical mechanism of damage nucleation and growth, a physics-based multiscale model is considered for fatigue damage assessment in metallic aircraft structures. A guided-wave based sensing approach is utilised to enable effective damage detection in a common structural hotspot: a lug joint. Finite element analysis is carried out with piezoelectric wafers bonded to the host structure and the simulated sensor signals are analysed. A damage classification strategy is developed, which integrates physically motivated time-frequency approaches with advanced stochastic modelling techniques. In particular, a variational Bayesian learning scheme is used to estimate the optimal model complexity automatically from the data, adapting the classifier for real-time use. Classification performance is studied as a function of signal-to-noise ratio and results are reported for the detection of fatigue crack damage in the lug joint. An adaptive hybrid prognosis model is proposed, which estimates the residual useful life of structural hotspots using damage condition information obtained in real-time.

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