Temat: finite-element model - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: A finite element model development as a part of process of energy absorption material selection
Autorzy:: Jakubowski, R.
Skorupka, Z.
Powiązania:: https://bibliotekanauki.pl/articles/244612.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: RASTAS Spear
material
energy absorption
finite element model
LS-DYNA
Opis:: The Warsaw Institute of Aviation major role in the RASTAS Spear project was to design an energy absorption system for the space probe lander. As the system was meant to be unmanned, the main requirement was to use no active solutions like parachute or rocket propulsion (less complexity in application and thus more reliability). A group of various materials was chosen to be tested. Tests campaign was divided into three stages: static compression tests, low speed dynamic tests and high speed dynamic tests. The high-speed dynamic tests were divided into two substages. In the first one simple cube specimens were tested to obtain data necessary for second substage in which full-scale object was tested. Having valuable data from experiments, numerical simulations in LS-DYNA software were carried out and then the results were compared. Based on experimental data several iterations during finite element model developing process were made. That process allowed setting up properly simulation by changing and adjusting properties such: material models, contact types, element formulation and other important constants. The finite element simulation results showed a good correlation with experimental data. The knowledge gained from numerical model optimization in connection with experimental data allowed for creating faster and more accurate energy absorbing material selection methodology. This methodology was successfully used in subsequent projects in which Institute of Aviation took part and also can be used in other future applications.
Źródło:: Journal of KONES; 2016, 23, 3; 217-223
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Validation of the FEM model of the Mi-24 tail boom and vertical stabilizer
Autorzy:: Reymer, P.
Powiązania:: https://bibliotekanauki.pl/articles/242236.pdf
Data publikacji:: 2011
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: finite element method
Mi-24 helicopter numerical model
validation
Opis:: The scope of this work was the validation process of the numerical model of the Mi-24 helicopter tail boom and vertical stabilizer. In order to obtain a detailed geometry of the actual structure the sophisticated reversed engineering techniques were used. The measurement was performed using two separate techniques: one based on digitalphotogrammetry and other based on a three dimensional laser scanning with ATOSIII scanner. The numerical model was created with use of the obtained geometry, available technical documentation and detailed inspection of the structure. The obtained FEM model was validated using strain measurements of the real structure during characteristic flight maneuvers. A system of foil strain gauges was installed on the tail boom in previously selected locations. Calibration process, using known loads, was performed in order to determine response of the measurement system. To enable a quick and reasonable comparison of results from the experiment and calculations a special element was introduced in the FEM model. Their task was to monitor local strains in places corresponding to those where the strain gauges were installed. Detailed analysis of results confirmed, that after some minor modifications, the developed finite element model represents the actual structure reasonably well. Particular attention was paid to the representation of the boundary conditions and how to implement loads, which can significantly affect the obtained results. The analysis carried through confirms, that the presented validation technique, based on strain measurements, allows verifying a complicated numerical model in a relative cheap, fast and reliable way.
Źródło:: Journal of KONES; 2011, 18, 2; 369-376
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Application of cohesive model in fracture mechanics by WARP3D
Autorzy:: Gałkiewicz, J.
Powiązania:: https://bibliotekanauki.pl/articles/243336.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: finite element method
cohesive model
fracture mechanics
fracture process
Opis:: In the paper cohesive model implemented in WARP3D code and an example simulation of crack growth analysis ispresented. Cohesive model is an effective tool for a crack growth analysis and it was a main reason to invent it. For the "dassica" constitutive equation the crack growth simulation in the finite element method (FEM) is not possible without an additional crack growth criterion. In the commercial FEM codes cohesive model is not very popular unfortunately. Usually it can be applied as user implemented elements. However there is a code free of charge with high reliability acknowledged in the literature with cohesive elements in standard library. This program is WARP3D and it is dedicated to numerical simulations of three dimensional fracture mechanics problems. The Dugdale's model, void creation, the cellular model of material, the cohesion-decohesion curve, behaviour of cohesive element, comparison of curve shapes for brittle and ductile fracture, the profile of the cohesive element in WARP3D, specimen geometry, changes of crack shape under increasing load, opening stress distribution in the uncracked ligament are presented in the paper.
Źródło:: Journal of KONES; 2008, 15, 1; 69-77
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Modelled phenomenon of burr formation during machining
Autorzy:: Preś, P.
Skoczyński, W.
Powiązania:: https://bibliotekanauki.pl/articles/248036.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: burr formation
cutting
finite element simulation
2D numerical model
Opis:: A model of burr formation on the edge of the workpiece in the course of machining is presented. The material being machined, the cutting tool and the machining parameters were modelled. Material properties and type of its deformations have been modelled with the use of a constitutive Johnson - Cook model. Material damage initiation criteria and associated damage evolution have been modelled with the use of the ductile damage and the Johnson- Cook damage initiation criterion. Simulations of the machining process for different depths of cut were carried out. The real burr formation presented by Hashimura was compared with the modelled one. The influence of the cutting parameters on the form and size of burr has been analysed. Calculations have been realised utilising finite element method with the use of nonlinear analysis in ABAQUS/Explicit environment. Based on simulation results, the assessment of the form and size of burr has been made. Burr height was used to evaluate its size, which was derived according to ISO 13715 standard. The goal was to obtain a model that reliably reflects the behaviour of material during machining, with particular emphasis on supporting the creation of cutting phenomenon of burr formation. The results of simulation and computational analysis confirmed that the model reflects the real behaviour of the material.
Źródło:: Journal of KONES; 2012, 19, 1; 333-338
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Experimental verification of the developed soil model describing the propagation of vibration wave in the ground
Autorzy:: Bednarz, J.
Powiązania:: https://bibliotekanauki.pl/articles/246492.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: finite element method
propagation of vibration wave in the soil
Drucker-Prager material model
Opis:: The problem of propagation of vibration waves in soil caused by passing trains and vehicles is an important issue for the assessment of their influence on environmental impacts and engineering structures such as bridges, viaducts, historic architecture and residential buildings. The issue is complex because the nature of the soil is heterogeneous and the groundwater level changing depending on the season and this creates great difficulties in developing a theoretical model of vibration wave propagation. The paper presents developed numerical model of soil consisting of 4.3 million cubic finite elements based on the geological properties of soil. Developed model based on Drucker- Prager material model, which is often used in numerical methods for simulating the behaviour of different soil types. In addition, the material properties of the soil was specially prepared and allowed to use them directly in the material model used. Both concrete (building) and steel (plate forcing) were modelled using an isotropic material model. Element size was set at 300 mm. This value was determined by the adopted frequency range studied (0 to 100 Hz) and due to verification by simulation results of experimental studies in which excitation has been implemented in the frequency of 33 Hz (base frequency of excitation signal) and 66 Hz (second harmonic of excitation signal). The cut-off frequency 100 Hz defines a minimum wavelength propagated in the soil (based on the stiffness and density of the soil) and 10 finite elements was adopted at a wavelength, which is 3 meters to the ground, for the correct mapping of a sinusoidal waveform. Subsequently, experimental studies were performed to verify the model from which the conclusions are presented in the work. The work was carried out in a research project 4875/B/TO2/2010/38 financed by Ministry of Science and Higher Education.
Źródło:: Journal of KONES; 2012, 19, 3; 31-39
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Strength analysis of polymer conical gear wheel made with 3D printing technique
Autorzy:: Śpiewak, Szczepan
Awrejcewicz, Jan
Powiązania:: https://bibliotekanauki.pl/articles/243848.pdf
Data publikacji:: 2019
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: exoskeleton
strength analysis
finite element method
FEM
material model of acrylonitrile-co-butadiene-co-styrene
conical gears
Opis:: The article deals with the problem of designing conical gears with a curved line contour. The contour of the tooth flank is described by means of a helix and involutions. In the work, a conical gear designed to drive of the lower limb rehabilitation exoskeleton has analysed. Parameters of the conical gearbox have been adapted to design requirements of the exoskeleton. Gear wheels were made with ABS material using 3D printing technique. The article presents the results of strength calculations obtained using the method classical design of the gear wheals described in the norm ISO 6336-1996. In the strength calculations, bending and contact stresses were taken into account. Creating the contour of gears was aided through the gearbox wizard available in Inventor program. The work contains the results of a static tensile test of the material from which the gear wheels were made. In experimental and numerical studies, the orthotropy of the material used was taken into account. The orthogonal values of the Young’s modulus, the Poisson’s ratio and the Kirchhoff’s modulus were determined. The publication also includes partial results of fatigue tests in the area of normal stresses. In the research used to finite element method (FEM), determine of internal loads in the gear. A structure of the FEM model is described in detail. Maximum values of contact pressures determined by use to FEM models have been compared with the results obtained on the basis of Hertz’s formulas. The article presents basic geometrical and strength parameters of the designed gear. The work demonstrates the validity of the material models used. Limitations in the application of the classic method of calculating conical gears made of orthotropic materials have been indicated. The results of analytical and numerical calculations are presented in tabular and graphical form.
Źródło:: Journal of KONES; 2019, 26, 3; 235-242
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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