Browsing by Author "Kozubal, Janusz"

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Access status: Open Access ,
Analiza przemieszczeń poprzecznie obciążonego pala w trójwymiarowym ośrodku liniowo-sprężystym o cechach losowych
(Wydawnictwa AGH, 2009) Bauer, Jerzy; Kozubal, Janusz; Puła, Wojciech; Wyjadłowski, Marek
The paper presents a probabilistic modelling of displacements of a foundation pile. The pile is subjected to lateral loading implemented in the pile's head. The pile is embedded in a layered linearly-elastic random medium. The loading is considered as a random variable. The probabilistic approach to this problem as a three-dimensional one constitutes a new result in comparison with other earlier published. The base of the solution is the three-dimensional modelling by the finite element method. A series of results can be obtained under various values of elastic characteristics of the medium under consideration. Next by a non-linear regression procedure a response surface is obtained. To get the final response surface an iterative algorithm has been applied. The final response surface allows a reliability analysis. The failure criterion is an exceeding of an allowable displacements threshold by deformed pile's head. By numerical examples a vital effect of the random variability of the lateral force as well as random variability of the elastic modulus of the upper layer has been demonstrated.
Access status: Open Access ,
Wpływ zmienności losowej parametrów podłoża na ocenę niezawodności pracy pala obciążonego siłą poziomą
(Wydawnictwa AGH, 2010) Bauer, Jerzy; Kozubal, Janusz; Puła, Wojciech; Wyjadłowski, Marek
This paper presents probabilistic modeling of pile displacement under random lateral forces acting on the pile head. An original numerical model is presented incorporating a randomly varying elastic modulus with depth. The probabilistic computations take into account different values of the coefficients of variation as well as correlation coefficients of random variables. The probability of excessive displacements and corresponding reliability indices were evaluated. The computed examples show that the displacement exceeding the allowable value is determined by the force acting at the head of the pile and by the variation of the elastic modulus of the soil.
Access status: Open Access ,
Zapis warunku plastyczności w języku skryptowym FlexPDE oraz FLAC 2D
(2008) Kozubal, Janusz; Wyjadłowski, Marek
In the paper the describing of linear-plastic material behaviour in Finite Elements codes: FlexPDE and MRS FLAC is presented. The discussion is restricted to linear elastic-perfectly plastic material, two-dimensional plane strain and associated flow rule. For describing linear-elastic material behaviour (for general stress states): stress-strain behaviour in elastic range, yield function or failure function, flow rule, definition of strain hardening (softening) are needed. In the solution the tension stresses are limited and showed like convex multi segment line.