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EN
In this paper, Finite Element Method (FEA) harmonic analysis of the changes caused by raising the centerline of a large, precise lathe is presented. Two standalone dynamic subsystems (“Rotor Shaft” and “Support”) are revealed and the resilience of the “Rotor Shaft” to the raising procedure is stated. The three subsystems of the “Support” class are much more dynamically pliable, only the main eigenmodes of the shaft and supports are excited in the 0…100 Hz range (MR1“Half-wave” and MS1…3 “Radial pecking”). Mounting the lunette suppresses the MR1 peak by a factor of two; therefore the lunette is strongly recommended, with an optional tuned-mass damper (TMD). The support’s resonant frequencies MS1…3 are more deleterious for precision; they should be omitted or weakened using TMD’s that are attached to the supports. For the above conditions, raising the centerline (up to 600 mm) may be included in the lathe renovation program.
EN
The article presents the way of creating calculation model of mold to foaming of cooling furniture for needs of conducting strength analysis by using Finite Element Method. The method of creating model is described in detail taking into account of modeling techniques available in NX system, the division of model into finite elements (discretization) by using threedimensional, two-dimensional, one-dimensional elements was visualized. Finally, the results of numerical simulations in the form of stresses distribution in areas of considerable straining of structure was presented.
PL
W artykule przedstawiono sposób tworzenia modelu obliczeniowego formy do spieniania mebli chłodniczych dla potrzeb przeprowadzenia analiz wytrzymałościowych przy wykorzystaniu Metody Elementów Skończonych. Szczegółowo opisano metodę kreowania modelu z uwzględnieniem technik modelowania dostępnych w systemie NX, zobrazowano podział modelu na elementy skończone (dyskretyzację) przy wykorzystaniu elementów trójwymiarowych, dwuwymiarowych oraz jednowymiarowych. Przedstawiono wyniki z przeprowadzonych symulacji numerycznych w postaci rozkładu naprężeń w obszarach o znacznym wytężeniu.
EN
As part of a cooperation project between the Institute for Machine Tools, Stuttgart, Germany, and EMO Systems/Nuton GmbH, Berlin, Germany, a prototype of a multiaxial force platform with disturbance compensation for the measurement of the cutting forces in machine tools was developed. Commercially available products based on piezoelectric technology are subject to a degree of measurement uncertainty and therefore characterized by various disturbances. Interpreting measurement data of the commercially available products is complex, time-consuming and prone to errors. This paper describes the mechanical design and the simulation of the multiaxial force measuring system with the finite element method (FEM) as well as the conceptual development of a reduced model for a multibody simulation with the purpose of implementing a compensation algorithm. The measurement uncertainty was reduced by using appropriate hardware and software for the compensation of the various disturbances so that the application of the force platform would also be possible in the industrial application for the process diagnosis, the control and the regulation in machine tools. Systems based on strain gauge technology have some advantages in the field of zero-point stability and also provide a less expensive solution. For the disturbance compensation, an additional force and torque sensor system with eight channels was used for the detection of the platform displacement and inclination. With the help of appropriate algorithms for the disturbance compensation and their integration in the evaluation software, the disturbances could be reduced to a minimum.
EN
The efficient use of resources are becoming more important due to economic and environmental requirements. In widely used forming processes like deep drawing an avoidance of lubricants – namely dry deep drawing – is a key factor for saving resources. In this paper, a combined approach consisting of a macro-structured tool design and a special modified protective coating is presented. The combination ensures a stable process with a sufficiently wide process window under dry conditions. The absence of lubricants in critical areas has to be compensated by tetrahedral amorphous carbon ta-C films which is additionally structured by Direct Laser Interference Patterning (DLIP) for further improvement of the tribological performance.
EN
In the present research, a physical-geometric-feature of continuous yarn in a plain woven fabric was created and its FE model was analysed by considering the two key issues of woven fabric, the crimp and inter-yarn friction. The basic parameters of Young’s modulus of single yarn and the inter-yarn friction coefficient were investigated for practical fabrics in tensile and pull-out tests. FE analysis indicated that the stress-strain curves of the FE model were effective in evaluating the equivalent modulus of a woven fabric by comparing with a tensile experiment on Twaron CT® Plain Woven Fabric. In addition, a simplified three dimensional model of the unit cell of plain woven fabric (UCPW) was employed to quantitively investigate two important fabric characteristics – the crimp rate of the yarn and inter-yarn friction-to determine their influence on the mechanical properties of the fabrics. Furthermore, we used FE analysis to evaluate how the crimp rate and inter-yarn friction affected the mechanical properties by determining the equivalent modulus of single yarn and UCPW in both uniaxial and biaxial tensile loading. The stresses at representative nodal points and the mechanical interaction between yarns were also investigated from a microscopic perspective, and their deformation mechanisms were also analysed and discussed.
PL
W pracy stworzono fizyczno-geometryczną cechę przędzy ciągłej w gładkiej tkaninie i przeanalizowano jej model FE, biorąc pod uwagę dwa kluczowe zagadnienia tkaniny: karbikowatość i tarcie między przędzami. Zbadano podstawowe parametry: moduł Younga przędzy pojedynczej oraz współczynnik tarcia między przędzami. Analiza FE wykazała, że krzywe naprężenie-odkształcenie modelu FE były przydatne w ocenie tkaniny przez porównanie z eksperymentem rozciągania tkaniny Twaron CT® Plain Woven. Ponadto zastosowano uproszczony trójwymiarowy model komórki elementarnej z gładkiej tkaniny (UCPW) do ilościowego zbadania dwóch ważnych cech tkaniny: szybkości fałdowania przędzy i tarcia między przędzami – w celu określenia ich wpływu na właściwości mechaniczne tkaniny. Ponadto wykorzystano analizę FE, aby ocenić, w jaki sposób szybkość fałdowania i tarcie między przędzami wpłynęły na właściwości mechaniczne. Dokonano tego poprzez określenie równoważnego modułu pojedynczej przędzy i UCPW zarówno przy jednoosiowym, jak i dwuosiowym obciążeniu rozciągającym. Naprężenia w reprezentatywnych punktach węzłowych i mechaniczne interakcje między przędzami zbadano również z perspektywy mikroskopowej, a także przeanalizowano i omówiono ich mechanizmy deformacji.
EN
Three-dimensional angle-interlock woven composites (3DAWCs) are widely used for their excellent mechanical properties. The most significant feature is the existence of the undulated warp yarns along the thickness direction, which makes it interesting to study the mechanical properties in the warp direction. The quasi-static tensile behavior of a layer-to-layer 3DAWC along the undulated warp direction was studied by experimental and finite element analysis (FEA) methods. Based on the experimental results, the typical failure mode involving fibers, resin, and their interfaces was found. According to the FEA results, the stress concentration effect, key structural regions, and microstructural (yarn and resin) damage mechanism were obtained, which provided effective guidance for structural optimization design of the 3DAWC with stronger tensile resistance performance. In addition, the three-step progressive failure process of the 3DAWC under quasi-static tensile load was also described at the “yarn–resin” microstructural level.
EN
This paper presents the Co-Simulation of a Small Wind Turbine (SWT) with Permanent Magnet Synchronous Generator (PMSG). It combines Simulink, Maxwell and Simplorer software’s to show the electrical machine behaviour connected with the power electronics’ circuit. To the control of the system the Maximum Power Point Tracking (MPPT) algorithm is used. The finite element analysis (FEA) was used to design the novel electrical machine with permanent magnets. Application of FEA method for PMSG modelling guarantee exhibit a more accurate behaviour over simplified Simulink models, also during motor and power electronics faults.
PL
W artykule przedstawiono zagadnienie symulacji małej turbiny wiatrowej z generatorem synchronicznym z magnesami trwałymi (PMSG) przy wykorzystaniu trzech niezależnych środowisk programistycznych (tzw. współsymulacja). Podczas analizy wykorzystano wspólne obliczenia z programów Simulink, Maxwell i Simplorer. Model generatora wykonany został w środowisku Maxwell (z wykorzystaniem metody elementów skończonych (FEM)), co pozwala na jego dokładną analizę zarówno w stanach statycznych jak i dynamicznych. Układ energoelektroniki zamodelowano w programie Simplorer a układy sterowania (przy wykorzystaniu metody MPPT) w środowisku Simulink. Taka analiza pozwala na uzyskanie dokładnych rezyltatów w różnych warunkach pracy – w tym podczas uszkodzenia maszyny lub elementów energoelektroniki.
EN
The subject of this article is the finite element method (FEM) simulation of the multi-layered rectangular composite beam subjected to three-point bending test. The study is focused on the composite beams made of glass or carbon fibre-reinforced laminates (glass fibrereinforced polymer [GFRP] and carbon fibre-reinforced polymer [CFRP]) for which different laminate stacking were addressed. Three beam geometries with various length-to-thickness ratios included short beam shear (SBS) test, provided the beam is short relative to its thickness, which maximised the induced shear stresses. Simulation included the application of Tsai-Hill, Hoffman, Tsai-Wu, Hashin and Puck failure criteria to perform the composite beam failure analysis wherein the matrix and fibre failure were considered separately. Numerical failure studies also aimed to verify the beam failure modes and the participation of stress tensor elements in material failure.
EN
This paper is a case study conducted to present an approach to the process of designing new products using virtual prototyping. During the first stage of research a digital geometric model of the vehicle was created. Secondly it underwent a series of tests utilising the multibody system method in order to determine the forces and displacements in selected construction nodes of the vehicle during its movement on an uneven surface. In consequence the most dangerous case of loads was identified. The obtained results were used to conduct detailed strength testing of the bicycle frame and changes its geometry. For the purposes of this case study two FEA software environments (Inventor and SolidWorks) were used. It has been confirmed that using method allows to implement the process of creating a new product more effectively as well as to assess the influence of the conditions of its usage more efficiently. It was stated that using of different software environments increases the complexity of the technical process of production preparation but at the same time increases the certainty of prototype testing. The presented example of simulation calculations made for the bicycle can be considered as a useful method for calculating other prototypes with high complexity of construction due to its systematized character of chosen conditions and testing procedure. It allows to verify the correctness of construction, functionality and perform many analyses, which can contribute to the elimination of possible errors as early as at the construction stage.
EN
Purpose: Modelling of biomechanical behaviour of heart valve materials aids improvement of biofunctional feature. The aim of the work was assessment of influence of material thickness of leaflets of artificial aortic valve on displacements and stresses during opening phase using finite element analysis (FEA). Design/methodology/approach: The model of aortic valve was developed on the basis of average anatomical valve shapes and dimensions. Nonlinear dynamic large displacements analysis with assumption of isotropic linear elastic material behaviour was used in simulation (Solidworks). The modulus of elasticity of 5.0 MPa was assumed and Poisson ratio set to 0.45. The rigidly supported leaflets was loaded by pressure increasing in the range 0-55 mmHg in time 0.1 s. Leaflets with material thickness 0.13 and 0.15 and 0.17 mm were analysed. The thickness was simulated with shell finite elements. Findings: The highest stresses were observed in the areas of fixation of the leaflets near the scaffold and were lower than dangerous value of fatigue of polyurethanes. Increasing the thickness of valve leaflet material in the range of 40 micrometres resulted in reduction of the valve outlet by almost 10 percent. Research limitations/implications: The FEA was limited to the isotropic linear-elastic behaviour of the material albeit can be used to assess leaflet deformation during dynamic load. Practical implications: Leaflets design may be start from efficient FEA which helps estimation of material impact on stress and fold formation which can affect local blood flow. Originality/value: Aortic heart valve leaflet material can be initially tested in dynamic conditions during opening phase with using FEA.
EN
Purpose: The aim of the study was to determine forces which are transferred to supporting teeth during the treatment with the midpalatal device with Hyrax screw and to evaluate orthodontic and orthopaedic effects based on displacement analysis. Design/methodology/approach: The finite element method (FEM) was used to simulation the midpalatal expansion forces activated by the screw pre-loaded during a turn of 180° which corresponds to daily recommended value. Distribution of expansion forces of Hyrax device was calculated as reaction forces on elastic supports with stiffness corresponding to the teeth working on periodontal ligament in alveolar bone. Findings: On the basis of the displacement analysis was observed the movement of supporting teeth by a value higher than 0.1 mm which corresponds to the recommended daily value. The midpalatal suture splitting forces were determined on the first premolars with a value of 32.8 N and on the first premolars of 44.2 N. Research limitations/implications: The studies did not take into account the shape of palate other craniofacial bones and their stiffness. Practical implications: Adjusting the stiffness of the device to degree of ossification midpalatal suture and teeth mobility. Searching for new solutions which eliminate the negative phenomenon of tilting teeth during the expansion of maxilla and recommending a surgically assisted techniques. Originality/value: The simulation confirmed that treatment with Hyrax screw gives a uniform expansion with values of forces corresponded to stiffness of premolar and molar teeth. The studies have indicated a possibility of tendency to tilting the supporting teeth what is a negative phenomenon.
EN
The paper presents the results of the conducted tests of torsional stiffness of the VOSCO S106 passenger car, as well as the validation process of these tests by means of numerical analyzes using the FEM finite element method. The most important element of the vehicle structure is the part of the spatial frame or the safety cage. Engine, brake system, fuel system and steering system, suspension as well as body and parts, their mounting nodes, hinges, locks, etc. are attached to the frame. The frame must therefore have adequate strength to protect the driver in the event of a tipover or impact. The frame is usually made of steel pipes with the prescribed dimensions and strength according to regulations. The torsional stiffness of the vehicle chassis has a significant influence on its driveability and therefore is an important parameter to measure. In this article, the torsional stiffness of the vehicle frame is calculated experimentally, which was then verified by finite element analysis (FEM) using the Altair HyperWorks program.
EN
The paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hybrid Fibre-Reinforced Polymer (nHFRP) bars manufactured using the pultrusion process. Hybridization of less expensive basalt fibres with carbon fibres leads to more sustainable alternative to Basalt-FRP (BFRP) bars and more economically-efficient alternative to Carbon-FRP (CFRP) bars. At the same time the properties of the proposed bars can be modified by changing the bars configuration. The New-Developed HFRP bars were subjected to tensile axial loading to investigate its structural behaviour. The effect of hybridization on tensile properties of HFRP bars was verified experimentally by comparing the results of tensile test of HFRP bars with non-hybrid BFRP bars. It is possible to improve and predict the final mechanical characteristics of HFRP bars through mechanical hybridization of constituents and their volume fractions before it will be produced. The analytical/numerical considerations and experimental testing showed the same tendency in obtained results. In pre-manufacturing phase it was set that for the final mechanical properties, the influence of bar configuration is less important than the influence of different volume fractions of fibres. In addition, it was assumed that the preferable location of carbon fibres will be in the core region due to technological problems. It is worth to mention that the difference in obtained strength characteristics between analytical and numerical considerations was very small, however the obtained results were much higher than results obtained experimentally. Authors suggested that lower results obtained experimentally can be explained by imperfect interphase development and therefore attempted to improve the chemical cohesion between constituents by adding nanosilica particles to matrix consistency.
PL
W artykule zostały przedstawione najnowsze postępy w zakresie zachowania mechanicznego hybrydowych prętów FRP (HFRP) oraz nano-hybrydowych (nHFRP) produkowanych w procesie pultruzji. Hybrydyzacja włókien bazaltowych z włóknami węglowymi prowadzi do bardziej zrównoważonej alternatywy dla prętów na bazie włókien bazaltowych (BFRP) i bardziej ekonomicznej alternatywy dla prętów FRP na bazie włókien węglowych (CFRP). Jednocześnie właściwości proponowanych prętów można modyfikować zmieniając ich konfigurację. Nowo opracowane pręty HFRP poddano obciążeniu osiowemu przy rozciąganiu, aby zbadać jego zachowanie strukturalne. Wpływ hybrydyzacji na właściwości mechaniczne prętów HFRP zweryfikowano doświadczalnie, porównując wyniki próby rozciągania prętów HFRP z niehybrydowymi prętami BFRP. Możliwa jest poprawa i przewidywanie końcowych właściwości mechanicznych prętów HFRP poprzez mechaniczną hybrydyzację składników i ich udziałów objętościowych przed ich wyprodukowaniem. Analityczne i numeryczne rozważania oraz badania eksperymentalne wykazały tę samą tendencję w uzyskanych wynikach. W fazie przedprodukcyjnej ustalono, że dla końcowych właściwości mechanicznych wpływ konfiguracji pręta jest mniej ważny niż wpływ różnych udziałów objętościowych włókien. Ponadto założono, że preferowane położenie włókien węglowych będzie zaproponowane bliżej rdzenia prętów ze względu na problemy technologiczne. Warto wspomnieć, że różnica w uzyskanych charakterystykach wytrzymałościowych między rozważaniami analitycznymi i numerycznymi była bardzo mała, jednak uzyskane wyniki były znacznie wyższe niż wyniki uzyskane eksperymentalnie. Autorzy sugerują, że niższe wyniki uzyskane eksperymentalnie można wyjaśnić niedoskonałym rozwojem interfazy i dlatego próbowano poprawić spójność chemiczną między składnikami przez dodanie cząstek nanokrzemionki do konsystencji matrycy.
EN
The values of the resultant forces acting on the cutting teeth of BWEs can either be calculated or determined using experimental methods. Based on this, the position and parameters of the working organs during the cutting process are designed and built. The stresses and deformations of the teeth during the cutting process are influenced by their positioning on the excavator bucket, which is determined by the fitting mode of the teeth. In this paper, the stresses and deformations in the case of an existing tooth holder are analysed and a new type of tooth holder is proposed, using SolidWorks® software for this analysis.
EN
This study presents general conclusions resulting from elastic FEM analyses of several dozen of thin-walled structures designed with the use of the application version of the method of statically admissible discontinuous stress fields (SADSF). The conclusions are illustrated with examples of two original structures designed to work under torsional load. The structures are based on I-sections, whose all surfaces are accessible from outside. Despite that fact, torsional rigidity of the structures is very high. Additionally, in these structures, we examined the effects caused by modifications consisting in local stiffening of some elements by applying edge stiffeners on their borders.
PL
Praca przedstawia generalne wnioski z analiz sprężystych MES kilkudziesięciu konstrukcji cienkościennych, które zostały zaprojektowane z wykorzystaniem wersji aplikacyjnej metody statycznie dopuszczalnych nieciągłych pól naprężeń (SADSF). Otrzymane wnioski są prezentowane na przykładzie dwóch oryginalnych konstrukcji, które zostały zaprojektowane na obciążenie momentem skręcającym. Są to konstrukcje oparte na profilu dwuteowym, których wszystkie powierzchnie są z zewnątrz dostępne, a mimo to są bardzo sztywne na zakładany rodzaj obciążenia. Dla konstrukcji tych badano dodatkowo efekty powodowane poprzez wprowadzanie modyfikacji polegających na lokalnym usztywnieniu elementów poprzez odwijanie ich swobodnych krawędzi.
EN
With regard to the challenges in the automotive production sector, caused by political regulations of CO2 emissions, lightweight concepts are focussed by industrial development. Fibre reinforced plastics (FRP) represent an alternative material compared to monolithic steel. On the one hand FRP materials offer advantages like less density with high specific strength, on the other hand new production concepts and processes are needed. A possible approach is the combination of different forming processes for the production of new hybrid components. Polymer based and conventional sheet metal material characteristics differ strongly. Therefore an extensive material characterisation is needed as well as appropriate mathematical methods concerning the material modelling. This publication deals with the material characterisation of glass mat reinforced thermoplastic composite (GMT) and the finite element based design of a manufacturing process of hybrid components with metallic inlays.
PL
W artykule omówione zostało stanowisko do badania wytrzymałości konstrukcji nośnej pojazdów pasażerskich – głównie autobusów, zgodnie z wymaganiami zawartymi w Regulaminie EKG ONZ nr 66.
EN
The article discusses the stand for testing the strength of the super-structure of passenger vehicles – mainly buses, in accordance with the requirements of UN ECE Regulation No. 66.
18
Content available remote Structural analysis of KufaSat using ANSYS program
EN
The current work focuses on vibration and modal analysis of KufaSat structure using ANSYS 16 program. Three types of Aluminum alloys (5052-H32, 6061-T6 and 7075-T6) were selected for investigation of the structure under design loads. Finite element analysis (FEA) in design static load of 51 g was performed. The natural frequencies for five modes were estimated using modal analysis. In order to ensure that KufaSat could withstand with various conditions during launch, the Margin of safety was calculated. The results of deformation and Von Mises stress for linear buckling analysis were also performed. The comparison of data was done to select the optimum material for KufaSat structures.
EN
Purpose: The aim of this study was to determine the effect of bone mineral density (BMD) on the stress distribution in pelvic-hip complex (PHC) model which included bone structures and soft tissues. Bone mass changes in osteoporosis and osteopenia were considered in this analysis. In addition, the relations between force direction and stress distribution causing PHC fractures were determined. Methods: This paper presents the development and validation of a detailed 3D finite element model with high anatomical fidelity of the PHC and BMD changes in trabecular and cortical bones, modelled based on CT scans. 10 kN loading was induced on a model consisting of 8 ligaments, the pelvis, sacrum, femur in front and side directions. Results: For validation, the results of this model were compared to physiological stress in standing position and previous results with high-energy crashes under side impact load. Analysis of side-impact indicated the influence of BMD on femoral neck fractures, acetabular cartilage and sacroiliac joint delaminations. Front-impact analysis revealed the inferior pubic ramus, femoral neck fractures and soft tissue injuries, i.e., acetabular cartilage and symphysis pubis in osteoporosis and osteopenia. Conclusions: The elaborated PHC model enables effective prediction of pelvis injuries in high-energy trauma, according to Young-Burgess classification, and the determination of the influence of BMD reduction on pelvis trauma depending on force direction. The correlation between BMD and stress distribution causing varying injuries was determined.
20
Content available Numerical modelling of structures with uncertainties
EN
The nature of environmental interactions, as well as large dimensions and complex structure of marine offshore objects, make designing, building and operation of these objects a great challenge. This is the reason why a vast majority of investment cases of this type include structural analysis, performed using scaled laboratory models and complemented by extended computer simulations. The present paper focuses on FEM modelling of the offshore wind turbine supporting structure. Then problem is studied using the modal analysis, sensitivity analysis, as well as the design of experiment (DOE) and response surface model (RSM) methods. The results of modal analysis based simulations were used for assessing the quality of the FEM model against the data measured during the experimental modal analysis of the scaled laboratory model for different support conditions. The sensitivity analysis, in turn, has provided opportunities for assessing the effect of individual FEM model parameters on the dynamic response of the examined supporting structure. The DOE and RSM methods allowed to determine the effect of model parameter changes on the supporting structure response.
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