Wyniki wyszukiwania - BazTech

1

Modelling the shock absorber piston valve using 2-way fluid-structure interaction

Buczkowski Daniel, Nowak Grzegorz

Transport Problems

|

2021

|

T. 16, z. 4

45--57

EN

The aim of this study is to examine the strongly coupled Fluid-Structure Interaction approach as a comprehensive method of predicting the performance of the shock absorber piston valve. For this purpose, numerical simulation sand experimental testing are carried out. The coupled CFD-FEA numerical model described in this article, contrary to the attempts made so far, takes into account the influence of contact between valve discs and the initial conditions of the disc stack preload. The model is based on the actual valve geometry used in the shock absorber design. As a result, the described approach is intended for use in industrial applications in development works, in particular, at the conceptual stage. To prove the reliability of the model, two valve compositions are chosen to be measured on a test bench and modelled in FSI simulations. For both of them, a satisfactory level of correlation is achieved, with the correlation error below 10% and well-predicted valve opening points. As a result, it is proved that the 2-way FSI approach has great potential to be successfully used to investigate the damper valve operation.

2

Vibration of simply supported plates in contact with liquid by using membrane curvilinear elements

Sygulski Ryszard

Vibrations in Physical Systems

|

2020

|

Vol. 31, nr 3

art. no. 2020323

EN

This paper concerns the free vibrations of a simply supported plate in contact with liquid on one side. The plate is placed into a hole of an infinite rigid wall. The analysed problem is a coupled problem of the fluid-structure type. It is assumed that the fluid is inviscid and incompressible. The boundary integral equation is used for describing the hydrodynamic pressure. The plate equation is formulated in the form of two harmonic equations. The surface of the plate is discretized using triangular curvilinear 6-node elements of the membrane type. These elements are simultaneously the finite elements for the plate and the boundary elements for the liquid. Numerical examples of the free vibrations of circular and rectangular plates are considered and are compared with analytical and analytical-numerical solutions.

3

The vibrations induced by fluid flow in plates with different Poisson’s ratios

Burlaga Bartłomiej, Stręk Tomasz

Vibrations in Physical Systems

|

2020

|

Vol. 31, nr 3

art. no. 2020301

EN

A fluid interacts with every solid object that is submerged in its flow. In this paper, the dynamic instability of elastic solid is modeled and analyzed based on the benchmark model. It is caused by a continuous stream of vortices (known as von Kármán vortex street). In the presented approach, prerequisites are calculated to meet the necessary conditions for this phenomenon to occur. The main objective of this study is to determine the influence of different Poisson ratios on the intensity of a solid body’s deflection. In the first part, governing equations are presented. The following part describes the model domain as well as assumed parameters with chosen values explanation. The third part presents simulation specific information - mesh and applied options. The conclusion and possible real-life applications are preceded by obtained results.

4

Numerical simulations of the flows past rotating geometries

Simon Jakub, Stankiewicz Witold

Vibrations in Physical Systems

|

2020

|

Vol. 31, nr 3

art. no. 2020318

EN

In the present paper the numerical approach for the modeling of the flow past rotating geometries is presented. Practical methods for two cases are described: the one where whole domain is moving with uniform angular velocity, where the rotation might be included in the governing equations only (in the terms related to Coriolis and centrifugal forces), and the one where part of the domain is rotating, whereas another one is stationary. The second case is illustrated by examples describing the steady and transient flow around a rotating propeller and by a centrifugal pump. Simulations are performed using OpenFOAM CFD solver, with the models covering flow rotation: MRF (multiple reference frame) and AMI (arbitrary mesh interface).

5

Soil-structure-fluid interaction of the rectangular tank - seismic analysis

Kotrasová K.

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

|

2017

|

Z. 23 (173)

147-156

EN

Ground-supported tanks are used to store a variety of liquids. The fluid develops hydrodynamic pressure on walls and bottom of tank during an earthquake. This paper provides theoretical background for specification of impulsive and convective actions of fluid in liquid storage rectangular container by using analytical methods. Numerical model of tank seismic response - the endlessly long shipping channel was obtained by using of Finite Element Method (FEM), Arbitrary-Lagrangian-Eulerian (ALE), Fluid Structure Interactions (FSI) formulation in software ADINA. The results of the analytical methods and the numerical solution were compared for partially water filled channel grounded on hard soil or sub-soil 30 MNm-3. It was considered the horizontal ground motion of the earthquake in Loma Prieta.

PL

Zbiorniki naziemne są używane do przechowywania różnych płynów. Obecność płynu powoduje powstawanie ciśnienia hydrodynamicznego na ścianach i dnie zbiornika podczas trzęsienia ziemi. W artykule przedstawiono teoretyczne podstawy przy użyciu metod analitycznych dla określenia działań impulsywnych i konwekcyjnych płynu w prostokątnym pojemniku do magazynowania cieczy. Numeryczny model reakcji sejsmicznej zbiornika - nieskończenie długi kanał uzyskano, stosując metodę elementów skończonych (MES), równania Eulera-Lagrange’a, interakcję pomiędzy płynem i konstrukcją (FSI) w oprogramowaniu ADINA. Wyniki metod analitycznych i rozwiązania numerycznego porównano dla kanału częściowo wypełnionego wodą, uziemionego na twardej glebie lub podłożu 30 MNm-3. Analizowano ruch poziomy w trzęsieniu ziemi w Loma Prieta.

6

Fluid-structure simulation of a valve system used in hydraulic dampers

Czop P., Gąsiorek D., Gniłka J., Sławik D., Wszołek G.

Modelowanie Inżynierskie

|

2012

|

T. 14, nr 45

197--205

EN

The aim of this paper is to develop a method for optimizing the design of a disc spring valve system by reducing the aeration and cavitation effect which negatively influences the performance of a shock absorber. A fluid structure interaction (FSI) model is used in order to modify the geometry of the valve interior and, in turn, to achieve better performance of a shock absorber. The paper analyzes the pressure distribution along theflow paths inside the valve cavity to reduce the risk of aeration and cavitation, while other important engineering aspects are omitted, e.g. durability of disc-spring valve systems as discussed in [1]. A key measure of valve improvement was chosen as deterioration of the damping force level generated by a shock absorber vs. the number of cycles during continuous cycling of the damper . The objectives of this work are as follows: (i) to present a process for reducing the complexity of the geometry of a disc spring valve system in order to perform a combined fluid-structure simulation, (ii) to show keysteps of the simulation process focusing on interactions between fluid and structure domain and to review relevant simulation results, (iii) to describe practical aspects of the simulation process, including basic parameters and boundary conditions related to the applied commercial software, (iv) to make an optimization case study to show the application scope for the simulation methodology proposed in the paper, and to confront the simulation results with experimental investigations.

7

Goal-oriented mesh adaptivity for fluid-structure interaction with application to heart-valve settings

Wick T.

Archive of Mechanical Engineering

|

2012

|

Vol. LIX, nr 1

73-99

EN

We apply a fluid-structure interaction method to simulate prototypical dynamics of the aortic heart-valve. Our method of choice is based on a monolithic coupling scheme for fluid-structure interactions in which the fluid equations are rewritten in the 'arbitrary Lagrangian Eulerian' (ALE) framework. To prevent the backflow of structure waves because of their hyperbolic nature, a damped structure equation is solved on an artificial layer that is used to prolongate the computational domain. The increased computational cost in the presence of the artificial layer is resolved by using local mesh adaption. In particular, heuristic mesh refinement techniques are compared to rigorous goal-oriented mesh adaption with the dual weighted residual (DWR) method. A version of this method is developed for stationary settings. For the nonstationary test cases the indicators are obtained by a heuristic error estimator, which has a good performance for the measurement of wall stresses. The results for prototypical problems demonstrate that heart-valve dynamics can be treated with our proposed concepts and that the DWR method performs best with respect to a certain target functional.

PL

W artykule przedstawiono analizę zagadnienia oddziaływania płyn-struktura (FSI) w komputerowej symulacji pracy zastawki serca. Przedstawiono monolityczne sformułowanie tego zagadnienia, w którym równania dla struktury i płynu rozwiązywane są w pełnym sprzężeniu, przy czym do opisu ruchu płynu stosowane jest podejście typu Arbitrary Lagrangian-Euelerian (ALE). Zaproponowano metodę eliminacji zjawiska niefizycznego odbicia fal odkształceń struktury, polegającą na wprowadzeniu sztucznej dyssypacji energii tych fal w części brzegu obszaru położonej za zastawkami. W celu zwiększenia efektywności obliczeniowej wprowadzono lokalną adaptację siatki. W szczególności, porównano heurystyczne techniki adaptacji siatki z techniką opartą na wykorzystaniu ważonego residuum sprzężonego (Dual Weighted Residual, DWR). Przedstawiono wyniki obliczeń testowych demonstrujące poprawność zaproponowanego podejścia oraz skuteczność metody adaptacyjnej DWR.

8

Vulnerability analysis of aircraft fuselage subjected to internal explosion

Dacko A., Toczyski J.

Archive of Mechanical Engineering

|

2011

|

Vol. LVIII, nr 4

393-406

EN

The most important task in tests of resistance of aircraft structures to the terorist threats is to determine the vulnerability of thin-walled structures to the blast wave load. For obvious reasons, full-scale experimental investigations are carried out exceptionally. In such cases, numerical simulations are very important. They make it possible to tune model parameters, yielding proper correlation with experimental data. Basing on preliminary numerical analyses - experiment can be planned properly. The paper presents some results of dynamic simulations of finite element (FE) models of a medium-size aircraft fuselage. Modeling of C4 detonation is also discussed. Characteristics of the materials used in FE calculations were obtained experimentally. The paper describes also the investigation of sensitivity of results of an explicit dynamic study to FE model parameters in a typical fluid-structure interaction (FSI) problem (detonation of a C4 explosive charge). Three cases of extent of the Eulerian mesh (the domain which contains air and a charge) were examined. Studies have shown very strong sensitivity of the results to chosen numerical models of materials, formulations of elements, assumed parameters etc. Studies confirm very strong necessity of the correlation of analysis results with experimental data. Without such a correlation, it is difficult to talk about the validation of results obtained from "explicit" codes.

PL

W pracy przedstawiono wybrane aspekty modelowania i symulacji numerycznych odporności struktury cienkościennego kadłuba lotniczego na obciążenia wywołane falą uderzeniową, generowaną przez wewnętrzną detonację ładunku wybuchowego o masie m0. Charakterystyki mechaniczne materiałów przyjęto z pomiarów eksperymentalnych. Zastosowano technikę sprzężenia oddziaływań między strukturą a płynem, Arbitrary Lagrangian-Eulerian, z opcją erozji zniszczonych elementów. Przeanalizowano mechanizmy zniszczenia struktury w zależności od lokalizacji ładunku wybuchowego. Rozpatrzono wpływ różnych parametrów modelu obliczeniowego na wyniki analiz. Zbadano również wpływ wymiarów przestrzeni eulerowskiej na wyniki. Wykazano bardzo silną wrażliwość analizy na przyjęte parametry, wybrane sformułowania elementów (opcje), modele materiałów. Wskazuje to na konieczność korelacji symulacji numerycznych z wynikami eksperymentalnymi. Bez możliwości takich porównań trudno mówić o walidacji modelu obliczeniowego.

9

Modelowanie dynamiki oddziaływania płyn struktura w MES

Dacko A., Zieliński K.

Systems : journal of transdisciplinary systems science

|

2004

|

Vol. 9, No. sp. I

267-275

PL

Istotne informacje dotyczące odpowiedzi dynamicznej układu na obciążenia wybuchowe lub udarowe można uzyskać metodami symulacji numerycznych. Elastyczność formułowania zadania i bogactwo uzyskiwanych informacji są podstawowymi zaletami tego podejścia. Równie istotne znaczenie (lub często znacznie większe) mogą mieć aspekty zapewnienia bezpieczeństwa alternatywnych badań doświadczalnych. Bezpieczne uzyskanie informacji dotyczących obciążeń, które mogą dziaiać na załogę pojazdu w przypadku obciążeń od fali wybuchu, ma podstawowe znaczenie w określeniu stopnia narażenia życia, czy w prostszych przypadkach - ergonomii.

EN

The paper presents alternative load modeling for structures loaded by blast pressure wave. The classical approach, using external codes for pressure generation and subsequent implicit time integration of structure dynamics was compared to an alternative approach, taking advantage of Arbitrary Lagrange-Euler coupling, allowing for simultaneous calculation of pressure wave propagation and explicit integration of structural equations of motion. The discussion of results of performed tests are presented.