Wyniki wyszukiwania - BazTech

1

CAD supportive in design of multichannel pipe for automotive application

Kuczek Ł., Mroczkowski M., Richert M.

Journal of Machine Construction and Maintenance - Problemy Eksploatacji

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2017

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no. 4

71--80

EN

It is necessary to carry out investigations on device behaviour before it will work in real conditions. Helpful tools are CAD systems and numerical simulations on virtual geometric models. They allow relatively cheap and fast analysis of devices without using expensive real models. This paper presents a method of multichannel pipe design with the help of a CAD system in terms of its strength and working conditions as an internal heat exchanger with carbon dioxide as a refrigerant. Two aluminium alloys were chosen: AA 3103-H112 and AA 6060-T6, and several shapes of channels. Results show that the selection of proper materials is one of the most important stages. It affects the strength of the pipe. A second significant parameter is the shape of external channels. It has been shown that it is important to choose proper value of radius R1 (corner between upper area of external channel and lateral surface of external channel). For the analysed type of multichannel pipe, the most appropriate value of radius R1 was 1 mm. As for heat exchange between fluids in internal and external channels, an important parameter was the thickness of the wall between the mentioned channels. It has been demonstrated that heat exchange efficiency depends on wall thickness and on the way of achieving this.

PL

Często konieczne jest przeprowadzenie badania zachowania się urządzenia zanim będzie pracowało w warunkach rzeczywistych. Jednym z przydatnych narzędzi to umożliwiających są systemy CAD oraz symulacje numeryczne przeprowadzane na wirtualnych modelach geometrycznych. Pozwalają one na dokonanie stosunkowo taniej i szybkiej analizy urządzenia bez konieczności użycia kosztownych modeli rzeczywistych. W artykule przedstawiono metodę projektowania rury wielokanałowej przy pomocy systemów CAD pod kątem ich wytrzymałości i warunków pracy jako wewnętrznego wymiennika ciepła z dwutlenkiem węgla, pełniącym rolę czynnika chłodniczego. Do analizy wybrano dwa stopy aluminium: 3103-H112 i 6060-T6 oraz kilka różnych kształtów kanałów. Wyniki pokazały, że dobór odpowiednich materiałów jest jednym z najważ- niejszych etapów projektowania rur. Ma to wpływ na wytrzymałość rury. Drugim istotnym parametrem jest kształt kanałów zewnętrznych. Wykazano, że dobór odpowiedniej wartości promienia R1 (narożnik pomiędzy górną i boczną powierzchnią kanału zewnętrznego) jest istotny. Dla analizowanego typu rury wielokanałowej wartość promienia R1 równa 1 mm była najbardziej właściwa. W przypadku wymiany ciepła pomiędzy płynami w kanałach zewnętrznych i wewnętrznym ważnym parametrem była grubość ścianki pomiędzy wymienionymi kanałami. Wykazano, że efektywność wymiany ciepła zależy od grubości ścianki oraz od sposobu osiągnięcia jej zmiany.

2

Computer aided adaptive system design with engineering systematics and manufacturing

İrsel G.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 4

83--96

EN

This research practically discusses and presents the stages of design process in product development. Design process was realized through CATIA. The product developed is an agricultural device called as “disc harrow”. Therefore, agricultural details are presented together with machine design. A roller system is added to disc harrow in this study. Thus; the current system and the additional roller system are discussed with the principles of methodological construction and design objectives are defined. Both the current system and the additional roller system are designed in parallel with these objectives. Structural stress analysis is performed at different kinetic positions of the disc harrow connection of the roller system. System design is achieved by considering the feedback from such analyses and design objectives. The hereby design is obtained. The additional roller system is mounted and field survey is carried out. Contribution of the roller to disc harrow process, defined design objectives, ratio of the realization of design objectives and results of stress analyses are evaluated.

3

Optimal internal dissipation of a damped wave equation using a topological approach

Münch A

International Journal of Applied Mathematics and Computer Science

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2009

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Vol. 19, no 1

15-37

EN

We consider a linear damped wave equation defined on a two-dimensional domain [...], with a dissipative term localized in a subset [...]. We address the shape design problem which consists in optimizing the shape of [...] in order to minimize the energy of the system at a given time T. By introducing an adjoint problem, we first obtain explicitly the (shape) derivative of the energy at time T with respect to the variation in [...]. Expressed as a boundary integral on [...], this derivative is then used as an advection velocity in a Hamilton-Jacobi equation for shape changes. We use the level-set methodology on a fixed working Eulerian mesh as well as the notion of the topological derivative. We also consider optimization with respect to the value of the damping parameter. The numerical approximation is presented in detail and several numerical experiments are performed which relate the over-damping phenomenon to the well-posedness of the problem.

4

Analiza połączenia spawanego zaprojektowanego metodami nośności granicznej

Markiewicz I.

Eksploatacja i Niezawodność

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2008

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nr 3

12-21

PL

Praca przedstawia wyniki kształtowania metodami nośności granicznej oraz przybliżonych analiz sprężystych MES i numerycznych badań zmęczeniowych, spawanego połączenia nakładkowego blach, które wykonane w sposób tradycyjny ma wysoki współczynnik koncentracji naprężenia i niską trwałość zmęczeniową. Na podstawie skonstruowanego statycznie dopuszczalnego pola naprężeń i kinematycznie dopuszczalnych mechanizmów zniszczenia określono kształt połączenia, a przede wszystkim oszacowanie teoretyczne szerokość łączenia blach (szerokości spoiny). Z przeprowadzonych analiz wynika, że optymalna - ze względu na wielkość maksymalnej koncentracji i trwałości zmęczeniowej - szerokość spoiny pokrywa się z otrzymanym wymiarem teoretycznym. Połączenie zaprojektowane metodami nośności granicznej ma ponad dwukrotnie mniejszy współczynnik koncentracji naprężenia w stosunku do tradycyjnego i około 50 krotne większą trwałość zmęczeniową.

EN

The paper presents the results of application of the limit analysis methods, approximate elastic analyses FEM and numerical fatigue investigations to overlapping weldments in sheet-metal plates. When made with the use of traditional methods, these weldments exhibit high concentration of stresses and low fatigue life. By constructing statically admissible stress fi elds and kinematically admissible collapse mechanisms, one can determine the shape of weldment, and estimate theoretically the weld leg length. The analyses performed by the author show that the weld leg length optimal for minimizing stress concentration and maximizing fatigue strength is consistent with that calculated theoretically. The weldment designed with the use of limit analysis methods has, in comparison with a traditional welded joint, a twofold lower stress concentration factor, and over 50 times higher fatigue life.

5

A multiobjective approach to the shape design of HTSC magnetic bearings

Di Barba P., Pałka R.

Przegląd Elektrotechniczny

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2007

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R. 83, nr 11

228-230

EN

The shape design of the excitation system of a high-temperature-superconductor (HTSC) magnetic bearing is revisited in terms of multiobjective design. It is proven how the concept of non-dominated solution, helps the designer to represent the feasible region in the objective space and identify its boundary. At the end of the proposed design procedure, a set of optimal geometries of the device ? or system to be synthetised is available.

PL

W pracy rozpatrzono problem wielokryterialnej optymalizacji kształtu układu wzbudzenia pola w łożysku magnetycznym z nadprzewodnikami wysokotemperaturowymi. Wykazano, że koncepcja rozwiązań niezdominowanych umożliwia projektantowi zdefiniowanie obszaru rozwiązań dopuszczalnych oraz identyfikację jego brzegu. Podano szereg rozwiązań optymalnych analizowanego problemu.

6

Analyses of plane stress discontinuity lines systems in oyane porous media

Bodaszewski W.

Engineering Transactions

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2005

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Vol. 53, iss. 4

397-414

EN

The paper presents the results of numerical analyses of certain properties of plane stress discontinuity lines systems, which are specific for the Oyane condition, and do not appear when one assumes other yield conditions, such as Huber-Mises or Tresca conditions. The results have been obtained by applying general algorithms that do not require formulating any individual relationships. The algorithms aid solving problems for any boundary conditions, of practically any type, which can be met in the problems of construction of discontinuous statically admissible fields, mainly the limit fields. In the assumed formulation, the solution consists in finding initially the fields arising around isolated nodes of stress discontinuity lines, and then integrating the fields into two-dimensional complex fields. Application of these algorithms makes it possible to quickly find all the existing solutions of the stress discontinuity lines around the nodes, at the same time eliminating the need of forecasting (guessing the solution), which until recently was the main difficulty in solving each new complex field. Physical justification of the Oyane condition is beyond the scope of this work.

7

Algorithms of the method of statically admissible discontinuous stress fields (SADSF). P. 3 Software implementations and example problems formulated for fields around nodes

Bodaszewski W.

Engineering Transactions

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2005

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Vol. 53, iss. 1

15-30

EN

Boundary problems, characteristic for the already-known fields around convex and concave corners, are used in this part of the paper as the examples to present juxtaposition of conditions, and to obtain a solution for general conditions of the system - important for the fields that appear around nodes. The presented variants of these systems and the sets of unknowns, after minor completion, give the basis for deriving series of elementary problems, which are necessary to create the algorithm for solving arbitrary boundary problems, such as those encountered in the fields around nodes. The algorithm created on such a basis does not require formulating any particular relationships, and its implementation makes it possible to find any solution to the field around the node. The solution, presented in an illustrative graphical form, can then be easily edited. In effect, it becomes possible to test, almost instantaneously, admissibility of the structures, and verify the existence of solutions on the physical plane. The paper also presents short description of properties of the fields around nodes that facilitates interpretation of the results. It is particularly useful in the cases when one obtains surprising results, for example when structural degenerations (collapses) appear. It is worth mentioning that, with boundary conditions formulated for fields around both the bove-mentioned types of corners, one obtains not only fields identical with the prototype, but also a whole variety of other fields that until now have been treated as different ones. Actually, these are the fields being solutions to the same boundary problem.

8

Algorithms of the method of statically admissible discontinuous stress fields (SADSF) . P. 4 Inegration of fields around nodes into planar complex fields

Bodaszewski W.

Engineering Transactions

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2005

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Vol. 53, iss. 2

119-131

EN

In this part of the paper, the author presents a general concepts of algorithms of two program modules that integrate component fields around nodes into planar complex fields. The first module, the auxiliary one called module C, is used to construct the objects of incidence of the regions and the lines that are generated automatically, based on a freehand sketch of the field structure - which can be drawn, for example, on the monitor screen by means of a mouse. The proper integration, however, is performed by the second module, called module B, which utilises both the incidences brought in by module C, and the solutions of component systems of stress discontinuity lines around nodes - the latter obtained using the module called A. The individual partial problems are still demonstrated here, and the example of the already known solution of the field type f90 is used for this purpose. Attention is also focussed on the effects of partial autonomy that are revealed in the integration problems. These effects consist in decoupling of two systems of conditions: the one defined on geometrical parameters, and that based on stress parameters. The conditions are utilised, for example, in the algorithms of the application version software for finding particularly complicated fields that could contain as much as several dozens of homogeneous regions. An example of such a solution is shown along with its application to forming complex elements of a structure. The example confirms once again great potential of the SADSF method.

9

Ujęcie aplikacyjne metody SADSF. Konstruowanie pól o wielkim stopniu złożoności

Bodaszewski W.

Mechanics and Mechanical Engineering

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2002

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Vol. 6, nr 3

23-30

PL

Przedstawiono aktualne możliwości kształtowania bardzo złożonych elementów konstrukcyjnych metodą statycznie dopuszczalnych, nieciągłych pól naprężeń /ang. SADSF/ - przy pomocy najnowszej wersji oprogramowania jej ujęcia aplikacyjnego Jak w każdym przypadku tego ujęcia, pola takie są konstruowane poprzez dobór oraz łączenie rozwiązań znanych, w tej pracy są to już jednak pola o właściwie dowolnym stopniu złożoności, praktycznie bez ograniczeń na liczbę obszarów jednorodnych. Całość jest prezentowana przy pomocy poglądowych rysunków i na przykładzie kształtowania powłoki oryginalnej konstrukcji 'ramy' nośnej samochodu - z krzyżowo rozmieszczonymi poprzecznicami - dzięki czemu nawet te elementy są zginane, a nie skręcane, jak ma to miejsce w 'ramach' tradycyjnych, obciążonych z zewnątrz momentem skręcającym.

EN

Possibilities of current shape design of very complex structural elements are presented by the method of statically admissible discontinuous stress fields /SADSF/ with use of the most recent version of the tool software in its application approach. As in every case of this approach, such fields are constructed by selection and assembling of known /ready-made/ solutions. In the present work these fields have an arbitrary degree of complexity, practically without limitations of the number of homogeneous regions. The whole work is presented in visual form by the example of the shape design of the shell of the truck frame with cross members - thanks to which even these elements are bended and not torsioned, as is the case in traditional frames loaded a torque moment.