Probabilistic Calculation of Fatigue Crack Progression Using Fcprobcalc Code

Abstract

The paper gives examples of the probabilistic assessment of a steel cyclic loaded structure. Fatigue progression of the cracks from the edge and from the surface is used as a basis for proposing a system of inspections of details which tend to be damaged by fatigue. The newly developed method Direct Optimized Probabilistic Calculation (DOProC method) was used for solution. The method was applied in FCProbCalc software. KeywordsDirect Optimized Probabilistic Calculation, DOProC, Safety Margin, Probability of Failure, Fatigue Crack Progression, Inspection of Structure, Random Variable. AbstraktPříspěvek je zaměřen na jeden z možných způsobů posouzení spolehlivosti cyklicky namáhané ocelové konstrukce s ohledem na vznik únavových trhlin z okraje a povrchu, které vede k návrhu systému prohlídek konstrukčních detailů náchylných na únavové poškození. Pro řešení pravděpodobnostní úlohy byla použita nově vyvíjená metoda Přímého Optimalizovaného Pravděpodobnostního Výpočtu (zkráceně POPV), implementovaná do programu FCProbCalc. Klíčová slovaPřímý Optimalizovaný Pravděpodobnostní výpočet, POPV, funkce spolehlivosti, pravděpodobnost poruchy, šíření únavové trhliny, prohlídka konstrukce, náhodná proměnná.

Probabilistic Failure Analysis of Steel Structures Exposed to Fatigue

“…The result of this method is similar to other probabilistic approaches: proposal of a system of regular inspections of the construction. Those computations were applied in FCProbCalc which was used for the mathematical modeling of propagation of fatigue cracks from the edge and surface [7,8]. A probabilistic reliability assessment of the constructions was also performed in this software -it was based on the exact definition of the permissible size of the fatigue crack.…”

“…Similarly to other probabilistic analyses, this information is used as a basis for proposing a system of inspections of the cyclic load construction [2,10]. In order to improve quality of probabilistic calculations, special software -FCProbCalc [7] -was developed. Using this software, the task can be solved flexibly in a userfriendly environment.…”

Probabilistic prediction of fatigue damage based on linear fracture mechanics

“…The chosen mean value a 0 = 0.2 mm with log-normal probability distribution represents a significant asymmetry histogram with a larger variance for a0 > 0.2 mm according to [29]. The probabilistic calculation was performed using FCProbCalc software ("Fatigue Crack Probability Calculation") [17], which has been developed using the aforementioned techniques. By means of FCProbCalc, it is possible to carry out the probabilistic modelling of propagation of fatigue cracks propagating from the edge and from the surface in a user friendly environment and to propose a system of regular inspections which should reveal damage to the structure.…”

ProbCalc - An Efficient Tool for Probabilistic Calculations

“…DOProC has proved to be a good solution in calculation of fatigue crack progressions in steel structures and bridges which are subject to cyclic loads. FCProbCalc is the software application which contains calculation routines for probabilistic calculation of progression of fatigue cracks from the edge and surface in structures subject to cyclic loads [7,10]. The starting point for this is a computational model based on linear fracture mechanics.…”