Wyniki wyszukiwania - Biblioteka Nauki

1

Badania niszczące w procesach badań materiałowych

100%

Szymański S. , Siuta J.

Dozór Techniczny

|

2006

|

tom z. 1

3--6

2

Connection capacity of the transition zone in steel-concrete hybrid beam

84%

Kozioł P. , Kożuch M. , Lorenc C. , Rowiński S.

|

2017

|

tom No. 25(2)

137--146

EN

The problem of transition zone of structural steel element connected to concrete is discussed in the following paper. This zone may be located for instance in specific bridge composite girder. In such case the composite beam passes smoothly into concrete beam. Because of several dowels usage in the transition zone, the problem of uneven force distribution were discussed through analogy to bolted and welded connections. The authors present innovative solution of transition zone and discuss the results, with emphasis put on the transition zone structural response in term of bending capacity, failure model and force distribution on the connection length. The article wider the already executed experimental test and presents its newest results.

PL

W artykule przedstawiono zagadnienie kształtowania połączenia elementu stalowego z elementem betonowym w strefie przejściowej belki hybrydowej. Strefa ta może być wykorzystana m.in. w nowatorskich rozwiązaniach zespolonych dźwigarów mostowych, umożliwiając ich swobodne kształtowanie podłużne poprzez płynną zmianę pomiędzy przekrojem zespolonym a betonowym. Przedstawiono różne rozwiązania konstrukcyjne strefy przejściowej oraz poruszono problem nierównomiernego rozdziału sił w połączeniach długich, jako jednego z głównych czynników wpływających na kształtowanie połączenia elementu ze stali konstrukcyjnej z konstrukcją betonową. Prototypowe rozwiązanie strefy przejściowej opisano na podstawie przeprowadzonego badania niszczącego omawiając najnowsze wyniki tego badania oraz analizując model zniszczenia i redystrybucję sił na długości strefy.

3

Analiza wytrzymałościowa oraz badania niszczące wirujących dysków

84%

Chlebus E. , Górski P. , Krot K. , Hufenbach W. , Czulak A.

|

tom R. 83, nr 1

69-69

PL

Przedstawiono wybrane analizy numeryczne dysków wirujących z dużymi prędkościami. Obliczenia wykonano za pomocą metody elementów skończonych. Celem analiz było poznanie mechanizmu zniszczenia dysków oraz wyznaczenie prędkości przy której dyski ulegną zniszczeniu. Szczególnie istotne z punktu widzenia badawczego było porównanie otrzymanych wyników dla dysków z kanałami prostymi oraz zakrzywionymi. Po wykonaniu analiz numerycznych wykonane zostały badania niszczące dysków, na specjalnej maszynie wytrzymałościowej, umożliwiającej zniszczenie badanych części poprzez obracanie ich z wysokimi prędkościami.

EN

Presents selected numerical analysis of high speed rotating discs. Computations has been made using finite elements method. The goal of the analysis was to understand the disc-destruction mechanism and to determine the destructive speed. Especially important was to compare results obtained for two different kinds of discs: discs with straight internal holes and discs with bent internal holes. Destructive tests has been made on a special machine by rotating discs at a high speed.

4

Ustalenie parametrów wytrzymałościowych popioło-żużla i piasku pylastego z wykorzystaniem niszczących badań nasypów modelowych

84%

Baran P. , Cholewa M.

|

2015

|

tom Tom 17, cz. 2

1463--1483

EN

Soil used as a material to form earth structures has been divided according to EN ISO 14688 on natural and anthropogenic soil. In the process of electricity and heat production, during combustion of carbonaceous material the various types of waste has been arising, such as: fly ashes, slags, ash-slags, etc. These wastes have a very good compaction properties, which is use in the construction of flood banks, dykes and embankments. The ashes are often used to improve and stabilize cohesive soils (which are characterized by a high degree of plasticity) and organic soils. The addition of fly ash improves the shear strength of the soil and reduce the deformability. It is important that before using anthropogenic soil for construction purposes, examine its suitability for use within a given type of a structure and the most effective method of verification are laboratory and field tests. Knowledge of geotechnical properties of soils is essential for the economic and safe design of earth structures. Stability calculations of a ground, slopes, and earth pressure on retaining structures, it would not be possible without the knowledge of soil shear strength and the values of the parameters defining this strength. Destructive tests of model embankments, made of two types of soil: natural (silty sand) and anthropogenic (ash-slag) have been performing for the purpose of this article. The aim of this study was to reach the real values of strength parameters - parameters that determine the safety of earth structures, and to confront them with strength parameters obtained from a standard tests. Problems with determination of real values of the angle of internal friction and cohesion in soil inspire to seek alternative methods involving the trial loading of embankment in real dimensions, simulating a usability load. That method requires in situ studies on a large scale of the embankment and to solve the inverse boundary problem. In this issue the known data are operational or limit loads, and the corresponding displacement, and the unknowns are the values of soil parameters. The authors of this article presented a similar to the described above method for determining the values of selected soil strength parameters, based not on the large scale but on laboratory test models in semi-technical scale. Parameters which we were looking for were: the angle of internal friction (F) and cohesion (c). After forming the embankments test model with slopes 45° and 60°, and performing overload tests, the limit load applied in top of the embankment model and slip surface have been obtaining. These data allowed to pass to the calculation phase using a back-analysis method by adopting one of the slopes stability methods estimation. It was assumed that the tested models of embankments were in limit state just before the destruction. So, the stability coefficient F of the slope had value equals 1,0. To perform a stability analysis one of the limit equilibrium method (Morgenstern-Price method) was used. This method rigorously approaches to meet all of the equilibrium conditions governing the soil. A detailed description of the method can be found in another publication of the authors [1]. The determination of the limit strength parameters has been describing in this article. The obtained landslide surfaces limited by a scarp and slip line have been dividing into 25 to 30 slices and the stability coefficients of model slopes was determining as follows: − range values of the angle of internal friction and cohesion of silty sand has assumed: F = 10–40˚ (slope 45°), F = 20–50° (slope 60°), c = 5–30 kPa, − range values of the angle of internal friction and cohesion of ash-slag has assumed: F = 10–50 (slope 45°), F = 20–60 ° (slope 60°), c = 0–40 kPa,− for all combinations of the F and c from aforementioned range values, the stability coefficient have been obtaining (table 3–6). On the basis of specific values of F, the pairs of F and c for which F = 1 (limit values of strength parameters) the limit curves have been plotting for all test models (Fig. 11 and 12). It was noted that smaller embankment failure load implicate the larger values of the limited angle of internal friction corresponding to lower limited cohesion. The range values of the angle of internal friction in this case is larger than in the soil that could take a larger load (limit curve is sharply inclined). There is also shown that the soil that could take a larger load is characterized by a smaller range of values of the angle of internal friction (limit curve is gently inclined). From the limit equilibrium methods point of view, using the strength criterion described by equation (2), the conditions of stability corresponded to limit state (F = 1) is obtained for any configuration of limit strength parameters, provided that the configuration of the angle of internal friction and cohesion is laying on the limit curve.

5

Thick-Walled Materials Weldability Assessment Based on Test SEP 1390

84%

Krawczyk R. , Kozłowski J.

Biuletyn Instytutu Spawalnictwa w Gliwicach

|

2016

|

tom Vol. 60, No. 3

42--48

EN

The article presents issues related to weldability assessment concerning thick-walled materials used in the making of steel welded structures. The article describes weldability assessment tests in accordance with the guidelines of test SEP 1390, recommended for thick-walled structural materials exposed to dynamic loads. The objective of the tests involved the assessment of the usefulness of test SEP 1390 when evaluating the weldability of thick-walled structural materials used for welded structures.

PL

W artykule przedstawiono zagadnienia związane z oceną spawalności grubościennych materiałów stosowanych do wytwarzania spawanych konstrukcjach stalowych. Przedstawiono próbę oceny spawalności według wytycznych SEP 1390 zalecaną do stosowania dla grubościennych materiałów konstrukcyjnych pracujących pod obciążeniem dynamicznym. Celem podjętego tematu była ocena przydatności próby SEP 1390 do oceny spawalności grubościennych materiałów konstrukcyjnych przeznaczonych na konstrukcje spawane.

6

Analysing the effect of changes in overlay weld geometry on test SEP 1390

84%

Krawczyk R. , Kozłowski J.

|

tom Vol. 60, No. 4

65--71

PL

Przedstawiono zagadnienia związane z oceną spawalności grubościennych materiałów stosowanych do wytwarzania spawanych konstrukcji stalowych. Przedstawiono analizę wyników badań przeprowadzonych w oparciu o próbę technologiczną spawalności grubościennych materiałów konstrukcyjnych wg wytycznych SEP 1390. W badaniach uwzględniono wpływ zmiany geometrii napoiny na przebieg próby technologicznej, a w rezultacie także na wynik końcowy oceny spawalności.

EN

The article presents issues related to the assessment of the weldability of thick-walled materials used when making welded steel structures. The article also discusses the analysis of test results based on the technological test concerning the weldability of thick-walled structural materials according to the guidelines of SEP 1390. The tests took into consideration the effect of the change in overlay weld geometry on the technological test, and, as a result, the final result of weldability assessment.

7

Optimizing Sand Moulding Process through Regression Models and Destructive Testing

67%

Abdulamer D.

|

2023

|

tom Vol. 23, iss. 4

163--168

EN

The main objective of the present study is enhanced of the sand moulding process through addressing the sand mould defects and failures, ultimately lead to improve production of the sand castings with well-defined of pattern profiles. The research aimed to reduce the cost and energy expenditure associated with the compaction time of the sand moulding process. Practical destructive tests were conducted to assess properties of the green sand moulds. Linear regression and multi-regression methods were employed to identify the key factors influencing the sand moulding process. The proposed experimental destructive tests and predicted regression methods facilitated measurement of the green sand properties and enabled evaluation of the effective moulding parameters, thereby enhancing the sand moulding process. Factorial design of experiments approach was employed to evaluate effect of parameters of water content and mixing time of the green sand compaction process on the mechanical properties of green sand mould namely the tensile strength, and compressive strength.