Wyniki wyszukiwania - BazTech

Ograniczanie wyników

3 2012

Powiadomienia systemowe

Sesja wygasła!
Sesja wygasła!
Sesja wygasła!
Sesja wygasła!

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: multi-axial stress states

Sortuj według:

Ogranicz wyniki do:

Numerical structural analysis of NPP reinforced concrete structures under seismic loading

Aleshin V., Seleznev V.

Journal of KONBiN

2012

No. 3 (23)

29--44

The paper describes an approach to the numerical analysis of response of nuclear power plant buildings including soil-structure interaction effects. A reinforced concrete structure of an NPP reactor building under operating and seismic loadings is considered. The simulated seismic load corresponds to a maximum designed earthquake of magnitude 7 (the peak ground surface acceleration is 0.12 g). The numerical analysis was performed by the finite element method in a 3D nonlinear statement using the FEM-programs ANSYS and LS-DYNA. Review of the numerical analysis results demonstrated that the presented technique can be successfully applied to seismic design of NPP structures.

W artykule opisano sposób analizy numerycznej reakcji (odpowiedzi) budynków elektrowni jądrowej, łącznie ze zjawiskami interakcji pomiędzy gruntem a konstrukcjami. Rozpatrywana jest żelbetowa konstrukcja budynku reaktora elektrowni jądrowej w warunkach roboczych i obciążeń sejsmicznych. Symulowane obciążenie sejsmiczne odpowiada maksymalnej sile trzęsienia ziemi założonej w projekcie, a mianowicie poziomowi 7 (maksymalne szczytowe wartości przyspieszenia gruntu wynoszą 0,12g). Analiza numeryczna została wykonana przy użyciu metody elementów skończonych dla trójwymiarowego modelu nieliniowego z wykorzystaniem programów ANSYS oraz LS-DYNA służących do analizy MES. Przegląd wyników analiz numerycznych wykazał, że zaprezentowana technika może być z powodzeniem stosowania do projektowania konstrukcji elektrowni jądrowych z uwzględnieniem zagrożeń sejsmicznych.

Microvoids Evolution in S235JR Steel Subjected to Multi-Axial Stress State

Kossakowski P. G., Trąmpczyński W.

Engineering Transactions

2012

Vol. 60, iss. 4

287-314

The article presents the results of the experimental and numerical analysis of microvoids evolution in elements made of S235JR steel under multi-axial stress state. The numerical simulations were based on the modified Gurson-Tvergaard-Needleman (GTN) material model, taking into account the impact of microstructural defects on the material strength. Two approaches were used, assuming a global and local damage of the structure of S235JR steel. In both cases, the evolution of microdamage (voids) and their impact on the strength and failure of the material were analysed. The results of numerical simulations were similar to the results obtained during microstructural examinations.

Effect of initial porosity on material response under multi-axial stress state for S235JR steel

Kossakowski P. G.

Archives of Civil Engineering

2012

Vol. 58, nr 4

445-462

The effect of the initial porosity on the material response under multi-axial stress state for S235JR steel using the Gurson-Tvergaard-Needleman (GTN) material model was examined. Three levels of initial porosity, defined by the void volume fraction f0, were considered: zero porosity for fully dense material without pores, average and maximum porosity according to the metallurgical requirements for S235JR steel. The effect of the initial porosity on the material response was noticed for tensile elements under multi-axial stress state defined by high stress triaxiality sigma m/sigma e = 1.345. This effect was especially noticeable at the range of the material failure. In terms of the load-bearing capacity of the elements, the conservative results were obtained when maximum value of f0 = 0.0024 was used for S235JR steel under multi-axial stress state, and this value is recommended to use in the calculations in order to preserve the highest safety level of the structure. In usual engineering calculations, the average porosity defined by f0 = 0.001 may be applied for S235JR.