The problem of effective gas extraction from Polish shale rocks is an interesting research subject for scientists. A properly selected proppant, which protects cracks from closing during the fracturing process, inestimably contributes to an increase of extraction. Grains of proppant are transported along with a fracturing medium to reach the deepest regions of the crack. The proper support of the crack provides an easy flow of gas, therefore it is important in terms of extraction efficiency. This paper shows the interactions of a proppant grain with the crack surface in shale rock. FEM analysis was conducted to observe the stress region, which is generated as a result of pressing the grain into the crack surface. A model of a sphere which was pressed into the rock model with constant velocity was applied. The received results of stress depend on material properties and a range of proppant grain pressing.
The paper proposes a comparative FEM analysis of gears solid model bodies, obtained with three different methods. The analytical method is based on the mathematical equations of the tooth flanks. It supposed to be the most accurate and precise solid modeling process. However, it reveals it’s limits by handling of surfaces that are not deduced mathematically, or in case of tooth geometries which needs to be modified in order to perform a quick test regarding the probably effects of the mentioned modifications. The solid subtraction- and the newly developed, mixed CAD method are pure CAD generating methods. As any discrete generating method, their precision is influenced by the fineness of the iteration steps. In case of the mixed CAD solution the precision is influenced by the filtering algorithm applied to the generated Points Cloud. The visual comparison of the three mentioned methods, was presented in previously published papers. The present paper validates the novel mixed CAD method comparing the FEA analysis of the generated solid models.
The paper presents the main types of power boiler steam superheater loads together with relevant standards applicable to superheater calculations. In the case of horizontal superheaters, due to their thermal expansion and assembly errors which are the effect of non-uniform support of the hanger tubes, extra loads are generated on the coil pipes. An FEM analysis performed for a selected superheater structure indicates that maximum stress values and the location where the stresses occur depend on the method of support of the superheater tubes. It is shown that maximum stresses in this structural element can be reduced by introducing appropriate tension of hanger bars supporting the superheater hanger tubes.
). Methods for global and local FEManalysis of riveted joints on the example of the PZL M28 Skytruck aircraft [in Polish], Master's Dissertation, Warsaw University of Technology. Jachimowicz J., & Wronicz W.(2008). Some problems of FEM modelling of riveted thinwalled aircraft structures [in Polish]. Przegląd Mechaniczny, 5 (2008). Wronicz, W., Kaniowski, J., Jachimowicz, J., & Szymczyk, E.(2009). Methods for FEManalysis of riveted joints of thin-walled aircraft structures within the IMPERJA project. Bridging the Gap between Theory and Operational Practice. In
10.2478/9788395771347-004 FEManalysis of the prototype BSG
4 FEMANALYSIS OF THE PROTOTYPE BSG
The prototype BSG designed in the previous chapter shall be verified using finite element
method (FEM) . A series of simulations is carried out using the FLUX2D software.
The generator geometry is drawn using Python script. The script is not depend upon the
version of the FLUX2D software, if the FLUX2D supports Python scripts. Therefore, the
generator simulations are more versatile. Results of FEM simulation, presented in this
The paper presents initial results of a new approach to FRP composite bridge construction that is presently being developed and tested in Poland. The concept combines lightweight concrete with FRP composites to create a durable highly optimised structure. The paper describes the bridge system itself and presents the research results on its development. The basic design is presented together with research results on its development: FEM analysis and a range of static test results of full-scale bridge beam experiments. The paper finishes with some test results of a full scale bridge that was constructed near Rzeszow in December 2015.
The article presents the analysis, project, and experimental examination of an original rigid riser for Coil Tubing Pipes. The principle of riser operation is based on the use of friction forces. The research included the FEM analysis of the designed riser, calculations of the required bolt tensions, and checking the effect of the clamping force on stress distribution in the pipeline. The results of computer simulation were verified on a specially designed test rig. The described riser design was implemented on the LOTOS Petrobaltic platform, thus eliminating the need for purchase and installation of expensive elastic risers.
This paper is focused on the process of designing the desired plastic component and injection mould by using the 3D CAD systems. The subsequent FEM analysis of the injection mould process was carried out in order to define shrinkage and deformation of the plastic material by CAE system. The dimensions of the mould were then modified to compensate the shrinkage effect. Machining process (milling and the laser texturing) of the mould was performed by using CAM systems. Finally, after the production of the plastic components by the injection mould technology, the inspection of the plastic component dimensions was carried out by CAQ in order to define the accuracy of the whole CAx chain. It was also demonstrated that CAx systems are an integral part of pre-production and production process.
The main goal of the research project was to develop and demonstrate the first Polish FRP composite road bridge, starting from concept design and material research, and going thru manufacturing technique selection, detailed FEM analysis and structural testing of elements. The R&D project comprises also the proof test of the completed bridge as well as structural monitoring in exploitation period. The objective of the paper is the description of the bridge and its structural solutions, i.e. FRP box girders and lightweight concrete deck slab acting compositely. Further the FEM analysis of the girder and the bridge span made on design stage has been presented. The VARTM manufacturing technique was used for girders production. Its main steps have been also presented. Finally the research on the new FRP box girder with LRC slab (hybrid girder) has been briefly showed. The full scale prototype girder with the total length of 22 m was tested to evaluate its carrying capacity, modes of failure, basic dynamic parameters as well as overall behaviour under ultimate static load. The FRP girder met the prescribed serviceability and safety criteria. The FEM model of the girder was validated against testing results and was further used for bridge design. Thanks to R&D project the first Polish FRP bridge is likely to be built late autumn 2015. The output of the research project gives a very promising future for the FRP composite bridge application. The research works showed in the paper have been partially financed by the Polish National Centre for Research and Development in the frame of the research project “ComBridge” (www.com-bridge.pl).
Reliable estimation of geotechnical parameters is often based on reconstruction of a complete loading process of subsoil on a specimen in laboratory tests. Unfortunately laboratory equipment available in many laboratories is sometimes limited to just a triaxial apparatus - the use of which generates difficulties whenever a non-axisymmetric problem is analysed.
The author suggests two simple operations that may be done to improve the quality of simulation in triaxial tests. The first one is based on the use of triaxial extension along the segments of the stress path p’-q-θ for which the Lode’s angle values are positive. The second one consists in a modification of the equivalent stress value in such a way that the current stress level in the specimen complies with results of FEM analysis.