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Selected modeling problems of monopile foundations used in the energy industry

Labocha Sławomir, Paluszyński Jarosław

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2021

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Vol. 10 Nr 2

77--87

EN

The paper presents selected practical aspects of the construction of monopile foundations used in the onshore power sector and analysis the effect of these solutions on the design of such structures. The basis for the evaluation of load capacity of such foundations was briefly discussed and the key factors that determine the ability to transfer loads from the structure to the ground were indicated. The main problem presented in the paper was to assess the impact of the reinforced concrete stay-in-place formwork piles built using the well technology. The considerations were supplemented with a computational example illustrating the thesis presented in the paper. A positive effect of prefabricated formwork rings on the load capacity of the foundation was demonstrated.

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Determination of Bolt Forces and Normal Contact Pressure Between Elements in the System With Many Bolts for its Assembly Conditions

Grzejda Rafał

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 1

116--121

EN

The paper put forward a thesis that modelling dissymmetric non-linear multi-bolted connections as a system is possible. Modelling of the systems composed of four subsystems on the assembly state was presented. These subsystems included: a couple of joined elements (a flange and a support), a contact layer between them, and bolts. The physical model of the system was described considering the tightening of bolts according to a specific sequence. In this model: the flange and the support were built using spatial finite elements, the contact layer was formed as the non-linear Winkler model, and the bolts were replaced with simplified models made of flexible beams. The calculation model which can be applied to determine the changes in bolt forces, as well as in the normal contact pressure between the joined elements during the tightening of the system and at its end, was presented. The results of sample calculations for the selected multi-bolted system were shown.

3

On the reconstruction method of ceramic foam structures and the methodology of Young modulus determination

Nowak M., Nowak Z., Pęcherski R. B., Potoczek M., Śliwa R. E.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 4

1219--1222

EN

In the present paper a finite element model was used to investigate the mechanical properties such as Young’s modulus of open-cell ceramic foam. Finite element discretization was derived from real foam specimen by computer tomography images. The generated 3D geometry of the ceramic foam was used to simulate deformation process under compression. The own numerical procedure was developed to control finite element mesh density by changing the element size. Several numerical simulations of compression test have been carried out using commercial finite element code ABAQUS. The size of the ceramic specimen and the density of finite element mesh were examined. The influence of type and size of finite element on the value of Young’s modulus was studied, as well. The obtained numerical results have been compared with the results of experimental investigations carried out by Ortega [11]. It is shown that numerical results are in close agreement with experiment. It appears also that the dependency of Young’s modulus of ceramic foam on density of finite element mesh cannot be ignored.

PL

W pracy przedstawiono metodę określania własności mechanicznych np. modułu Younga porowatych pianek ceramicznych o otwartych komórkach. Wykorzystując obrazy z tomografii komputerowej rzeczywistej struktury pianki otrzymano siatkę elementów skończonych. Przestrzenny obraz geometrii pianki wykorzystano do symulacji numerycznej procesu deformacji w próbie ściskania. Opracowano własną procedurę numeryczną do generowania elementów skończonych o różnej wielkości i kontroli gęstości siatki elementów. Przeprowadzono szereg symulacji numerycznych procesu ściskania pianek z wykorzystaniem programu elementów skończonych ABAQUS. Ustalono wpływ rodzaju i wielkości elementów skończonych jak również wielkości samej próbki na wartość modułu Younga wyliczonego dla próby jednoosiowego ściskania. Otrzymane numerycznie wartości modułów Younga porównano z wartościami z doświadczeń opublikowanych w pracy Ortegi [11]. Otrzymane rezultaty z symulacji numerycznych są w dobrej zgodności z doświadczeniem. Ustalono, ze wartości modułu Younga dla porowatych pianek ceramicznych zależy od gęstości siatki elementów skończonych i nie może być pomijana.