Wyniki wyszukiwania - Biblioteka Nauki

1

Analiza porównawcza wytrzymałości na ścinanie klejowych połączeń zakładkowych poliamidu po "szokach termicznych"

100%

Kłonica M.

Modelowanie Inżynierskie

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2021

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tom T. 42, nr 73

5--10

PL

W pracy przedstawiono wyniki badań porównawczych statycznej wytrzymałości na ścinanie zakładkowych połączeń klejowych wykonanych z poliamidu 6 po obróbce mechanicznej narzędziem nasypowym. Badania miały charakter porównawczy i dotyczyły połączeń klejowych poddanych zmiennym obciążeniom cieplnym oraz połączeń przed starzeniem w komorze „szoków termicznych”. Wykorzystano kleje na bazie żywic epoksydowych (Hysol 9466 oraz Hysol 9484). Analizowano wyniki badań wytrzymałości statycznej na ścinanie, uzyskanej dla różnych sposobów sezonowania próbek klejonych. Uzyskane wyniki z przeprowadzonych badań opracowano statystycznie z zachowaniem właściwych standardów naukowych. Zakres badań obejmował stosunkowo krótki cykl zmęczeniowy, wynosił on 500 oraz 1000 cykli przy zakresie zmienności –40oC ÷+60oC. Celem głównym badań było sprawdzenie podatności połączeń na zmiany wytrzymałości pod wpływem zmęczenia cieplnego.

EN

The paper presents a comparative analysis of static shear strength of single-lap adhesive joints of polyamide 6, after mechanical treatment with a coated abrasive tool. The research was of comparative nature and focused on adhesive joints subjected to variable thermal stress and adhesive joints not subjected to such shock. Adhesives based on epoxy resins were used (Hysol 9466 and Hysol 9484). The results of static shear strength tests of single-lap adhesive joints for different variations of material preparing were analysed. The obtained results were analysed statistically and in compliance with relevant scientific standards. The scope of tests covered a relatively short fatigue cycle, i.e. 500 and 1000 cycles in the range of temperatures between –40oC ÷+60oC. The main aim of the research was to determine the relation between joint strength and thermal fatigue.

2

Application of the Ozonation Process for Shaping the Energy Properties of the Surface Layer of Polymer Construction Materials

100%

Kłonica M.

Journal of Ecological Engineering

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2022

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tom Vol. 23, nr 2

212--219

EN

The properties of the surface layer of construction materials are very important for making adhesive bonds. The article presents the test results for surface free energy in PA6 polyamide subjected to surface layer modification using the ozonation process. To develop the surface geometrically, the samples were subjected to mechanical processing. The comparison of results demonstrated that ozonation is an efficient and eco-friendly method of modifying the surface layer. The article also presents the comparison results for measurements of selected surface roughness parameters.

3

Strength of Joints with “Hi-Lok” Fasteners in Aircraft Safety Considerations

63%

Kłonica M. , Bielawski R.

Advances in Science and Technology. Research Journal

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2019

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tom Vol. 13, no 4

87--93

EN

This paper reports on the results of strength tests of single-lap joints used in the aerospace industry with “Hi-Lok” fastener. The samples subjected to testing were made of EN-AW 2024 aluminium alloy and carbon composite. A part of the samples was additionally sealed with the use of Naftoseal MC-780 Class C sealant. The application of the MC-780 Class C sealant boosts the strength of a single lap joint of EN-AW 2024 T3 Al alloy and carbon composite. The strength test results were complemented with the analysis of selected 2D and 3D surface roughness parameters, and isometric images of the analysed surfaces. Additional information on the specimen surface quality was provided with photographic images taken with Keyence VHX-5000 microscope at x300 magnification. In the conclusion section of this paper, the study is summarised and its key findings are listed.

4

Influence of the Curing Process on the Fatigue Strength and Residual Strength of a Fiber Composite Estimation Using the Theory of Markov Chains

63%

Chatys R. , Kłonica M.

Advances in Science and Technology. Research Journal

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2023

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tom Vol. 17, no 2

53--62

EN

The paper deals with the influence of quality failure of matrix post-curing on the strength of such complex and difficult "new generation" materials as fiber composites, especially those with polymer matrix. The performed statistical analysis of the components determined the complexity of the layered composite structure. And the developed model of the weakest micro-volume presented in this paper has helped to describe not only the pre-dictable strength of the laminate, but also the nature of failure, taking into account the fiber stresses and/or the distribution of end strains in the structure of the composite under consideration. The strength of fibre composi-te structures based on Markov chain theory takes into account technological aspects during the curing process. The presented model was verified on the basis of literature examples and experimental data obtained during the testing process. Numerical results show good agreement with literature examples and measured data. The pre-sented model may represent a novel method that provides further insight into the curing process of epoxy re-sins.

5

The application of composite materials in the aerospace industry

51%

Skoczylas J. , Samborski S. , Kłonica M.

Journal of Technology and Exploitation in Mechanical Engineering

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2019

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tom Vol. 5, nr 1

1--6

EN

The paper investigates the growing popularity of composite materials concentrating on explanation of their advantages, especially taking into consideration composite materials used in the aerospace industry such as polymer matrix composites, metal matrix composites, ceramic matrix composites and smart composite materials. Various types of matrices and fibers are described with special emphasis on nanotechnology and opportunities to improve the properties of composites. The paper also presents selected examples of applications in the aerospace industry.

6

Influence of the Biocidal Agent Layer on Selected Properties of the Blown Polyethylene Film

51%

Jachowicz T. , Kłonica M. , Majewski Ł.

Advances in Science and Technology. Research Journal

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2020

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tom Vol. 14, no 4

315--325

EN

This paper discusses the problems connected with applying a biocidal substance onto the surface of a blown extruded polyethylene film in order to improve the functional properties of the film while maintaining its processing properties unchanged. The objective of the study was to determine the relationship between biocide application method and selected properties of the tube film. Two methods of biocide application onto the film surface were developed: one relied on spraying the biocide onto the hot melt surface directly during the extrusion process, while in the other the biocide was sprayed horizontally onto the blown film after the extrusion process. Biocide distribution uniformity, friction coefficients and surface free energy of the modified film were examined, and the quality and mechanical strength of heat- sealed joints were estimated. In addition, the geometric properties of the blown film were determined.

7

Experimental Study on Static and Dynamic Fracture Toughness of Cured Epoxy Resins

51%

Skoczylas J. , Samborski S. , Kłonica M.

Advances in Science and Technology. Research Journal

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2019

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tom Vol. 13, no 1

122--127

EN

The paper investigates experimental results of static and dynamic fracture toughness. The three-point bending test and the Charpy pendulum test were performed for two kinds of polymers: Epidian 5 epoxy resin cured with Z1 curing agent and Epidian 53 epoxy resin cured with Z1 curing agent. The comparison between the values of a maximum static and a maximum dynamic force are discussed as well as the values of static and dynamic fracture toughness, with special emphasis on microscopic views of crack propagation.

8

Comparative Tests of Shear Strength of Adhesive Lap Joints after Thermal Shocks

51%

Kłonica M. , Bielawski R. , Żokowski M.

Advances in Science and Technology. Research Journal

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2021

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tom Vol. 15, no 4

364--375

EN

This work presents the results of comparative tests for the determination of Young’s modulus and the static shear strength of adhesive lap joints, based on grade 316L steel. The tests also concerned the determination of the glass transition temperature of a certain adhesive composition: Epidian 57 epoxy resin with a 10% Z1 hardener content. The paper shows the test results for the surface free energy and selected surface roughness parameters, including photographs of the test specimens after destructive testing. The tests were comparative and performed on adhesive joints, with and without exposure to thermal cycling. The scope of the testing included a relatively short thermal cycling run of 500 cycles with a temperature variation of -40°C to +60°C. An analysis was carried out of the results from testing the static shear resistance of specimens manufactured using various methods of adhesive joint seasoning. The experimental test results were statistically processed in compliance with good research practice.

9

Fracture Surface Topography Parameters for S235JR Steel Adhesive Joints After Fatigue Shear Testing

45%

Kubit A. , Macek W. , Zielecki W. , Szwara P. , Kłonica M.

Advances in Science and Technology. Research Journal

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2023

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tom Vol. 17, no 5

130--139

EN

This paper presents the experimental results of a study investigating the effect of holes and notches made on the overlap ends on the strength of adhesive joints. Single-lap joints made of S235JR steel sheets bonded with Araldite 2024-2 epoxy adhesive were tested. For comparative reasons, static shear strength tests and high-cycle fatigue strength tests were performed. Adhesive-filled joints having three holes, each with a diameter of 3 mm, and notches, each 3 mm wide and 4 mm long, were tested and compared with reference joints, i.e. without modification. The assumption was to determine whether the structural modifications would reduce the peak peel and shear stresses that are typical of this type of joints. Results of the static strength tests showed no significant effect of the applied modifications on the strength of the joints. However, in terms of fatigue strength, the results demonstrated a significant improvement in fatigue life, the value of which increased in the low-cycle fatigue region by 328.6% for the joint with notches and by 640.8% for the joint with holes. A smaller yet still positive effect of the applied modifications was shown for high-cycle fatigue. For a variable load with the maximum value of 9 MPa, the fatigue life increased by 215.9% for the variant with notches and by 183.3% for the variant with holes. Surface topography of fatigue fractures was examined by determining roughness parameters on the overlap ends in the samples. Significant differences were shown, with the selected roughness parameters being significantly lower for the reference variant than for the variants with notches and holes. It was shown that the applied structural modifications led to increasing the fatigue strength to 8.5 MPa for the limit number of cycles equal to 2×106, when compared to the reference variant for which the fatigue strength was 8 MPa.

10

Selected Methods of Modifying the Surface Layer of a Carbon Composite

45%

Kłonica M. , Kubit A. , Perłowski R. , Bielawski R. , Woś S.

Advances in Science and Technology. Research Journal

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2024

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tom Vol. 18, no 1

270--277

EN

This article presents the results of a comparative study on the modification of the surface layer of carbon composites. Fibre-reinforced polymer (FRP) composite materials are heterogeneous and anisotropic materials, characterised by high strength, low density, corrosion resistance along with ease of processing and moulding, and are increasingly replacing metal alloys. They are widely used in aviation, automotive and transport applications. One example of a modern composite is carbon fibre-reinforced polymer (CFRP). This study presents the influence of selected modifications of the surface layer of a CFRP composite on the values of free surface energy (SFE) and surface topography. The resulting SFE values were analysed together with the contribution of the polar SFE and dispersive SFE components. The article also presents the test results related to selected 3D surface roughness parameters and includes photographs of the test specimens after surface layer modification. The results were statistically processed in compliance with good research practice.

11

Enhancing Fatigue Performance of Additively Manufactured Ti6Al4V – The Role of Surface Characteristics and Post-Processing Techniques

38%

Kurek A. , Żrodowski Ł. , Choma T. , Abramczyk I. , Kłonica M. , Wachowski M.

Advances in Science and Technology. Research Journal

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2024

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tom Vol. 18, no 6

280--290

EN

Geometrically complex objects are more and more often produced with the help of the so-called additive manufacturing commonly referred to as 3D printing. This technology proves itself to be effective in the field of medical industry due to processing potential of titanium alloys. Nonetheless 3D printing also has its drawbacks, the most severe being high roughness of printed elements’ area as well as the need to remove support structures created following the printing. Mechanical processing is commonly used for said parameters being enhanced. The completion of that process, however, takes a lot of time and prevents hard-to-reach elements from being reached. The task of this article is to provide a new method of firming the print’s surface and removing load-bearing structures. To achieve this, selective laser melting (SLM) technology will be used along with bathing prints in HF/HNO3 solution, all of which are supported by ultrasound.