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Scientific project: Development of components life assessment procedures

Project code  023-0692195-1749

Project name Development of components life assessment procedures

Senior researcher Damir Jelaska

Institution of employment University of Split, Faculty of Electrical Engineering, Mechanical Engineering a...

Program name Properties Optimization of Mechanical Devices for Innovative Applications

Scientific area technical science

Peer review group Mechanical Engineering;Shipbuilding;Traffic Technology and Transportation;Aeronautics and Space Technology

Summary There are many influnces on components life, and one can sort them in a three basic influences: - The influence of material and shap of the component. The influnces of the stress and strain concentrations belong here. - The influence of loading, it is their history. The influences of time character of loading (static, dynamic, stationary, nonstationary, random), mean stress and multiaxial state of stresses belong here. - The influence of enviroment, firstly of the temperature and corrosion. Any of those influences is adequately investigated in itself, So, timely variable stresses cause the material fatigue, the elevated temperature causes the creep of material, the timely variable temperature causes the heat fatigue, the stress concentration causes the cyclic accumulation of plastic starins leading to crack initiation, etc. However, jointly acting of two or more influences is insufficiently investigated, or is not at all. That is why the goals of this investigations are as follow: - For defined vibrations of turbo-engines disks and blades, it is for combined HCF and LCF loading at elevated temperatures, find the method for reliable determining their fatigue life. - Find the method to determine the (residual) fatigue life of the damaged structures subjected to random loading at elevated temperatures. - Develop the numericl model for determining the fatigue life of multiaxialy stressed elements subjected to elevated temperatures and freeting corrosion. - Describe the procedure of determining the crack path in the gear tooth root (bending) and at gear flanks (contact stresses), and the calculation procedure of the corresponding fatigue lives of the involute gears loaded by stress spectrum. - Determine the reliability of this estimations, it is determine the expectation and standard deviation of fatigue life on the basis of the expectations and standard deviations of the input data. Therefrom follows the basic hypothesis that this project intends to prove: By means of numerical tools and those of Fracture mechanics, and Service strength methods, it is possible to build the expert system which will enable the reliable determining the component life on the basis of defined material, shape and arbitrary stress history acting at it's critical area in defined enviroment (temperature, corrosion). We expect to reach the goals of the investigation and to prove the hypothesis.

Key words |Stress History|Fatigue,Fracture Mechanics,Operational Strength,Numerical Modelling,Involute Gear

Contract from 2.1.2007

Croatian scientific bibliography http://bib.irb.hr/lista-radova?sif_proj=023-0692195-1749&print=true&lang=EN

Address for communication
 Name and surname Damir Jelaska
 Street and no. FESB, R. Boškovića b.b., 21000, Split
 E-mail djelaska@fesb.hr
 Web address  fesb.hr/~djelaska
Project assistants 
  Name and Surname  Status
Damir Jelaska Project leader
Srđan Podrug Researcher
Danko Radica Scientific novice
Nenad Vulić Researcher