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1

Mechanical analysis of multilayer composite materials with duroplastic matrix after exposure to low temperatures

Krzak Anna, Nowak A. J.

Archives of Materials Science and Engineering

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2023

|

Vol. 122, nr 2

49--57

EN

Purpose: Cryogenic engineering is gaining more and more interest in various industry sectors, which leads to an intensive search for effective solutions. The article presents the findings of mechanical testing conducted on glass-epoxy laminates at room temperature and after long- term contact with liquid nitrogen. Design/methodology/approach: To compare the impact properties and flexural strength, the samples were tested under cryogenic and room conditions, and then the fracture locations were identified using the Leica DVM6 microscope. The study brings value to the emerging field of cryogenic engineering by providing valuable information on the mechanical properties of glass-epoxy composites under cryogenic conditions. Findings: It has been found out that immersing the glass-epoxy composites into the Dewar had minimal influence on impact and flexural strength properties. The most noticeable changes were observed in the case of the EP_4_2 composite. The material consists of a solution of brominated epoxy resin in an organic solvent. It is used to produce laminates in electrical engineering and printed circuits in electronics, where it should exhibit excellent impact properties. Research limitations/implications: One of the prospective research directions is a thorough analysis of the mechanical properties of the developed composite materials during cryogenic cycles. Originality/value: The study aims to determine the effect of different compositions of glass fabric-reinforced resin with a weight of 205 g/m2 on the mechanical properties of the developed composite materials at both room temperature and after long-term exposure to liquid nitrogen. Those investigations serve as surveillance for developing of new material solutions directed towards cryogenic applications and are essential for subsequent stages of research.

2

Ductility, load capacity and bending stiffness of scandinavian pine beams from waste timber strengthened with jute fibres

Wdowiak-Postulak Agnieszka

Drewno : prace naukowe, doniesienia, komunikaty

|

2022

|

Vol. 65, nr 210

art. no. 1644-3985.417.01

EN

The paper presents experimental studies of bending heterogeneous pine beams reinforced with jute fabrics. Pinus Sylvestris L, a Scandinavian wood species, was used in this study, originating from discard, subjected to 5-year atmospheric influences and biological degradation. The use of recoil wood is an excellent choice, forced by the increasing shortage of high-quality assortments and the need for economical management of scarce raw material. The article presents experimental results regarding the effectiveness of pre-stressed jute reinforcements in the tension zone of pine wood. The effects of using jute fabrics in beams were analysed, and the results were compared to beams without reinforcement. Additionally, the aim of the research is to investigate the influence of jute fabrics on the ductility of wooden beams. Research has been conducted on these polymer composites reinforced with natural fibres due to environmental awareness, their many advantages and, above all, the fact that they are sustainable materials. The conducted tests revealed that the jute fibres had a positive impact when applied to wooden beams and the load-bearing capacity increased by 24% and stiffness 24% compared to unreinforced beams. Moreover, the tests confirmed enhanced strength (24%) of reinforced pine beams in relation to the reference beams. In contrast, the ductility increased from 6.6% for reference beams to 75.7% for reinforced pine wood. Reinforcements with jute fibres have considerable ductility, which indicates that jute fibres are an excellent material for reinforcing the structure.

3

Effect of Cooling Rate on Mechanical Properties of New Multicomponent Fe-Based Amorphous Alloy During Annealing Process

Rezaei-Shahreza Parisa, Redaei Hossein, Moosavi Parisa, Hasani Saeed, Seifoddini Amir, Jeż Bartłomiej, Nabiałek Marcin

Archives of Metallurgy and Materials

|

2022

|

Vol. 67, iss. 1

251--254

EN

Fe-based bulk metallic glasses (BMGs) have been extensively investigated due to their ultrahigh strength and elastic moduli as well as desire magnetic properties. However, these BMGs have few applications in industrial productions because of their brittleness at room temperature. This study is focused on the effect of cooling rate on the mechanical properties (especially toughness) in the Fe41Co7Cr15Mo14Y2C15B6 BMG. For this aim, two samples with the mentioned composition were fabricated in a water-cooled copper mold with a diameter of 2 mm, and in a graphite mold with a diameter of 3 mm. The formation of crystalline phases of Fe23(B,C)6, α-Fe and Mo3Co3C based on XRD patterns was observed after the partial crystallization process. To determine the toughness of the as-cast and annealed samples, the indentation technique was used. These results revealed that the maximum hardness and toughness were depicted in the sample casted in the water-cooled copper mold and annealed up to 928°C. The reason of it can be attributed to the formation of crystalline clusters in the amorphous matrix of the samples casted in the graphite mold, so that this decrease in the cooling rate causes to changing the chemical composition of the amorphous matrix.

4

Mechanical properties evaluation of banana fibre reinforced polymer composites: a review

Gairola Surya P., Tyagi Yogesh, Gupta Nitin

Acta Innovations

|

2022

|

no. 42

59--70

EN

In today's fast-developing world, the use of composite materials is closely related to environmental pollution, renewable and biodegradable resources. A researcher is looking for environmentally friendly materials. Natural and synthetic fibres come in a wide range of shapes and sizes. Natural fibres include jute, straw wheat, rice husk banana fibre, pineapple leaf fibre, cotton, Sisal, Coir, Oats, and Bagasse. Every year, 13.5 tonnes of banana fibre are produced in India. Teabags, paper, and polymer composite reinforcement are just a few of the applications for banana fibre. This article focuses on the manufacture of banana fibre with epoxy and a variety of other natural fibres. By combining banana fibre with some current technology, waste will be reduced, and energy efficiency will be increased, all while supporting sustainability. Banana fibres are covered in this work, along with their uses, applications, and mechanical qualities, as well as how banana fibre might improve mechanical properties.

5

Effect of Modified Carbon Nanotubes Epoxy on the Mechanical Properties of Concrete Reinforced with FRP Sheets

Kazemi Hamid, Heydari Mostafa, Bamoharam Fateme Farash

Civil and Environmental Engineering Reports

|

2021

|

Vol. 31, no. 3

177--196

EN

Today, using Fiber Reinforced Polymer (FRP) sheets is one of the conventional methods in retrofitting concrete structures. Some factors affecting FRP sheets proper performance include mechanical properties, surface specifications, connector’s material and connecting approach in concrete elements. Previous studies showed that FRP epoxy resin and its basic surface have a significant impact on the ultimate bearing capacity. In line with the development of nanotechnology in recent years, this paper presents an experimental study to show the effects of adding the best percentage of nano-carbons to adhesive resin and evaluate the ultimate axial, shear and bending strengths in concrete samples. The results show that using FRP with carbon nanotube reinforced resins will significantly increase stiffness and ductility by 100%; moreover, it shows an effective increase of almost 13% in axial and flexural strengths of specimens.

6

Long-term mechanical testing of multifunctional composite fixation miniplates

Gryń Karol

Engineering of Biomaterials

|

2020

|

Vol. 23, no. 157

20--25

EN

This paper presents the analysis and comparison of the results of mechanical testing of dumbbell-shaped specimens and multifunctional fixation miniplates made via injection forming. Three types of materials were used: a) polylactic acid; b) a composite made of a polylactic acid matrix modified with tricalcium phosphate β-TCP; c) a composite made of a polylactic acid matrix modified with a mixture of bioceramic powders of tricalcium phosphate β-TCP and hydroxyapatite HAp. All the samples were stored in normal conditions, no special treatment was applied. Tests were conducted right after samples were prepared and they were repeated two and four years after preparation. The values of basic mechanical parameters and stress-strain curves were recorded and analyzed. The attention was focused on changes in time of tensile strength and stiffness of materials and implants. It was discovered that having been stored for four years in the open air, without sunlight, with no hermetic sealing, and no sterilization, all the materials (PL38, PL38/TCP, PL38/TCP/HAp) showed slight changes in mechanical characteristics when compared to the data of the initial samples tested after fabrication. These changes were not critical and did not adversely affect either tensile strength or Young’s modulus of the implants. All the analyzed miniplates maintained their mechanical properties at an acceptable level, fulfilling requirements for fixation devices for osteosynthesis. Therefore, it was proposed that the expiry date of these implants can be indirectly determined, based on long-term mechanical testing.

7

Mechanical behaviors of 3D printed lightweight concrete structure with hollow section

Wang Li, Jiang Hailong, Li Zhijian, Ma Guowei

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 1

219--235

EN

A practical revolution in construction could be realized by combining the potential of 3D concrete printing with lightweight cementitious materials to fabricate adeptly hollow structures. In this study, five concrete mixtures with different replacement rates of lightweight ceramsite sand to silica sand are prepared for extrusion-based 3D printability evaluation. To reduce the water absorption induced shrinkage and micro-cracks, the ceramsite sands were coated with polyvinyl alcohol. An optimized cementitious material was identified by harmonizing the fresh properties to the continuous printing process. Cubic and beam elements with four different types of interior hollow structures were designed and 3D printed based on the optimized lightweight mixture. The interior structures include cellular-shaped structure, truss-like structure, lattice-shaped structure with a square topology, as well as gridding shaped structure with triangle topology. The mechanical capacities of the printed samples were measured and evaluated by compressive tests for the cubic samples and four-points flexural bending tests for the beam specimens. Basing on the results, the rectangular lattice hollow structure demonstrates the best mechanical resistance to compression and the truss-shaped prism structure ensues the highest flexural properties. The stress distribution and failure process were also explored through discrete element method.

8

Fatigue failure analysis of three-layer Zr–Ti/Zr–Steel composite plates: an insight into the evolution of cracks initiated at the interfaces

Karolczuk Aleksander, Carpinteri Andrea, Robak Grzegorz, Derda Szymon, Prażmowski Mariusz

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 4

604--616

EN

Initiation and evolution of fatigue cracks at the interfaces in three-layer Zr–Ti/Zr–Steel composites is herein examined by in situ optical microscopy for the first time. Specimens cut out from three composite plates comprising Zr 700, Ti Gr. 1, and P265GH steel layers have been subjected to uniaxial fatigue cyclic loading. It is found that mechanical property mismatch between layers and defects at the interfaces can reduce the fatigue life of composite plates. An insight into the evolution of cracks initiated at the interfaces reveals that (1) most of the cracks grow into adjacent layers along two distinct planes, and (2) these cracks could lead to the fatigue failure of composites. One of these planes coincides with the adiabatic shear band orientation found in Ti Gr. 1 and Zr 700 layers. The interfaces in multilayer metallic composite could have excellent fatigue strength depending on their structural properties.

9

A comprehensive study of mechanical and acoustic properties of selective laser melting material

Barile Claudia, Casavola Caterina, Moramarco Vincenzo, Vimalathithan Paramsamy Kannan

Archives of Civil and Mechanical Engineering

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2020

|

Vol. 20, no. 1

30--40

EN

In this research work, four groups of selective laser melted specimens were built from AlSi10Mg-0403 powder. Each group represents the direction with respect to the bed in which the specimens are built (X, Y, Z and 45° orientation). The mechanical properties of the specimens are characterized in terms of yield strength, ultimate tensile strength, Young’s modulus and elongation at break. In addition to that, the acoustic emission (AE) during the testing was monitored using wide-band high-accuracy piezoelectric sensors. The AE results were related to the mechanical characteristics of the specimens in terms of the acoustic parameter-based data, the peak amplitude, cumulative energy and count rate. The mechanical results show that the specimens built along the z direction have relatively lower strength and it can be attributed to the borderline porosity formed during the SLM process. The acoustic results can identify the critical points of failure under loading. The AE technique proves to be a powerful tool in characterizing the mechanical property and can unveil the concealed information which cannot be identified directly from the mechanical results.

10

An investigation into fabrication and characterization of direct reaction synthesized Al-7079-TiC in situ metal matrix composites

Sujith S. V., Mahapatra Manas Mohan, Mulik Rahul S.

Archives of Civil and Mechanical Engineering

|

2019

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Vol. 19, no. 1

63--78

EN

The present study was attempted to highlight a novel direct reaction synthesis in which traditional casting plus rapid solidification techniques were implemented to produce Al-7079-TiC in situ composites with homogenous microstructure and improved dispersion strengthening by the reinforcing phases. Casted samples were effectively characterized by scanning electron microscopy followed by energy dispersive spectroscopy and X-ray diffraction. Ingot metallurgy showed a homogenous distribution of TiC particles inside the grain. This particle behavior acted as an excellent nucleation sites for the Al dendrites to grow unvaryingly. TiC reinforcements have semi coherent relationship with α-Al matrix. It was observed that eutectic boundary includes the second phases based on η (MgZn2) and Mg(Zn, Cu, Al)2. Almost 90% of the in situ reinforced TiC were homogenously distributed along the center of the grain. Thermal history conditions have shown an exothermic behavior during casting. Experimental results revealed the evolution of TiC particles in super-heated melt region, i.e. dissolution of titanium continued by reaction of titanium with diffused carbon in the Al matrix to form TiC particles. Further they acted as nucleation sites for the α-Al dendrites to grow homogenously. This study presents optimum process temperature for the Al-TiC in situ synthesis.

11

Druk 3D : wpływ gęstości ułożenia warstw na parametry mechaniczne

Swinarew A. S., Swinarew B., Popczyk M., Gabor J., Przybyła M.

Przetwórstwo Tworzyw

|

2018

|

T. 24, Nr 6 (186)

34--40

PL

Praca opisuje sposób przygotowania i modyfikacji filamentu wykorzystywanego w druku przestrzennym, a następnie sposób badania detali przygotowanych z wykorzystaniem technologii przyrostowej. Celem badania było wyznaczenie zależności pomiędzy zachowaniem się próbek podczas badania wytrzymałości na rozciąganie, a sposobem druku (gęstością ułożenia warstw).

EN

The work describes the method of preparation and modification of a filament used in spatial printing, and then a way to test the printed samples. The aim of the study was to determine the relationship between the behavior of the samples during the tensile strength test and the method of printing (density of the layering).

12

Stosowanie i wytwarzanie układów trójwarstwowych do budowy elementów aparatury procesowej

Pocica A., Groński T.

Przegląd Spawalnictwa

|

2018

|

R. 90, nr 4

66--68

PL

W pracy przedstawiono wyniki badań makroskopowych, mikrotwardości, określono własności mechaniczne dwóch układów trójwarstwowych składających się z cyrkonu-tytanu-stali i tytanu-stali-stali po platerowaniu wybuchowym zginania oraz odrywanie, a także analizę równoważnej grubości przetopień RGP.

EN

The work presents the results of the research of macroscopic, microhardness tests, RGP penetration thickness analysis and mechanical properties of two three-layer systems consisting of zirconium-titanium-steel and titanium-steel-steel after explosion cladding.

13

The Repair of Foundry Defects in Steel Castings Using Welding Technology

Mičian M., Koňár R., Hlavatý I., Winczek J., Gucwa M.

Archives of Foundry Engineering

|

2018

|

Vol. 18, iss. 2

177--180

EN

Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of foundry defects in steel castings also meets the requirements for the approval of welding procedures in accordance with the relevant valid legislation.

14

Geometrical and mechanical properties of polyamide PA 12 bonds in composite advanced pore morphology (APM) foam structures

Kovačič A., Novak N., Vesenjak M., Dubrovski P. D., Ren Z.

Archives of Civil and Mechanical Engineering

|

2018

|

Vol. 18, no. 4

1198--1206

EN

Adhesive bonds have very strong influence on mechanical properties of composite particulate metal foams. This study experimentally investigates for the first time the geometrical and mechanical properties of PA 12 adhesive bonds between spherical advanced pore morphology (APM) elements made of AlSi10 foam. A new experimentation setup for mechanical testing of bonds in APM structures is based on APM element puncturing. The results show that mechanical behaviour of adhesive bonds differs much from the basic mechanical behaviour of adhesive. Two different bond failure modes are identified, depending on the bond geometry. The geometrical and mechanical results are statistically interpreted for simpler representation, applicability, and modelling of bonds in APM composites in the future.

15

Własności mechaniczne pokryć operacyjnych stołów chirurgicznych

Wita K., Czakon K., Hajduga M.

Aktualne Problemy Biomechaniki

|

2018

|

z. 15

53--60

PL

W pracy przedstawiono wyniki badań własności wytrzymałościowych tapicerskich pokryć sprzętu medycznego. Przedmiotem zainteresowania badawczego były operacyjne stoły chirurgiczne, zaś celem pracy jakość użytkowa tapicerek, okalających stoły chirurgiczne. Do badań wytypowano trzy różne pokrycia obiciowe. Zakres pracy obejmował wycięcie próbek z tapicerek zdemontowanych ze stołów chirurgicznych oraz przeprowadzenie stosownych badań i analiz. Wnioski formułowano na podstawie wyników z przeprowadzonych pomiarów.

EN

The paper presents the results of research on strength properties of medical equipment covers. The subject of research interest were surgical operating tables. The aim of the work was to assess the utility value of upholstery surrounding surgical tables. Three different covers were selected for the tests. The scope of work included cutting out samples from upholstery dismantled from surgical tables and carrying out selected tests and analyzes. The conclusions were based on the results of the measurements carried out.

16

Charakterystyka struktury i właściwości stopu CuCrO.6 po zastosowaniu cyklicznego odkształcania metodą KoBo

Brzezińska A., Sobota J., Rodak K.

Przegląd Mechaniczny

|

2017

|

nr 7-8

42--45

PL

W pracy przedstawiono wyniki badań właściwości mechanicznych i fizycznych stopu CuCr0.6 po odkształcaniu metodą KoBo. Odkształcano materiał w stanie po odlaniu, po obróbce cieplnej: przesycanie (temp. 1000°C/3h) oraz przesycanie i starzenie (temp. 500°C/2h). Proces prowadzono przy parametrach (kąt obrotu matrycy 8°, częstość obrotu matrycy 5 Hz). Badania obejmowały przeprowadzenie statycznej próby rozciągania, pomiarów mikrotwardości oraz konduktywności elektrycznej. Scharakteryzowano strukturę stopu, wykorzystując mikroskopię świetlną i skaningową mikroskopię elektronową.

EN

In this paper the results of mechanical and phisical properties of CuCr0.6 alloy after applying KoBo deformation were presented. Material was deformed at the conditions: after casting, solution (1000°C/3h) and solution with ageing (500°C/2h). Process was performed at constant technological parameters as: torsion angle 8°, torsion frequency 5 Hz. The investigation include statical tensil strenght, hardness measurements and electrical conductivity. Structural investigations were performed by using light microscopy and scanning electron microscopy.

17

Experimental Study on the Riveted Joints in Glass Fibre Reinforced Plastics (GFRP)

Bielawski R., Kowalik M., Suprynowicz K., Rządkowski W., Pyrzanowski P.

Archive of Mechanical Engineering

|

2017

|

Vol. LXIV, nr 3

301--313

EN

The aim of the paper is to validate the use of measurement methods in the study of GFRP joints. A number of tests were carried out by means of a tensile machine. The studies were concerned with rivet connection of composite materials. One performed two series of tests for two different forces and two fibre orientations. Using Finite Element Method (FEM) and Digital Image Correlation (DIC), strain maps in the test samples were defined. The results obtained with both methods were analysed and compared. The destructive force was analysed and, with the use of a strain gauge, the clamping force in a plane parallel to the annihilated sample was estimated. Destruction processes were evaluated and models of destruction were made for this type of materials taking into account their connections, such as riveting.

18

Wartość użytkowa i odporność aseptyczna pokryć foteli dentystycznych

Wita K., Czakon K., Sobel A., Machnicka A., Hajduga M.

Aktualne Problemy Biomechaniki

|

2017

|

z. 12

89--95

PL

W pracy przedstawiono wyniki badań odporności aseptycznej oraz własności wytrzymałościowych pokryć sprzętu medycznego. Przedmiotem zainteresowania badawczego są fotele dentystyczne. Do badań mikrobiologicznych wytypowano tapicerkę roczną oraz piętnastoletnią. Następnie przeprowadzono posiew i inkubację wybranych gatunków bakterii. Badania mechaniczne wniosły informację o odporności tapicerek na ścieranie oraz przepuszczalności powietrza. Chemiczne natomiast, poinformowały o odporności wybarwień na działanie potu kwaśnego i alkalicznego. Wnioski formułowano na podstawie wyników z przeprowadzonych pomiarów. Stwierdzono, że klasa zachowań bakterii na tapicerkach pozostawała w funkcji czasu ich eksploatacji.

EN

The paper presents the results of resistance testing aseptic and the strength properties of the coatings of medical equipment. The subject of this research are dental chairs. For the microbiological examination a 15 year old and 1 year ago upholstery was selected. A further step is the seeding and incubation of selected species of bacteria. The mechanical tests carried out have made information about upholstery resistance to abrasion about upholstery resistance to abrasion and breath ability. Chemical whereas inform about the colour fastness to perspiration acid and alkaline sweat. The requests were formulated on the basis of the taken results. It was found out that the class behaviour a function of time of their operation.

19

Development and implementation of a testing method for the characterization of interlaminar delamination propagation in laminates under fatigue mode II loading conditions

Wilk J.

Prace Instytutu Lotnictwa

|

2016

|

Nr 4 (245)

251--261

EN

With no standardized methods being available the paper presents a procedure for experimental characterization of fatigue delamination growth under mode II loading conditions. The distinctive feature of the proposed algorithm is determination of crack length based on the specimen compliance. It eliminates the need of visual observations replacing it with compliance calibration performed at the end of the test. The testing methodology, using the end notch flexure set-up, is described step by step as well as calculations leading to obtaining the relationship between the delamination growth rate and strain energy release rate values in the form of Paris' law. The method was implemented in the Composites Testing Laboratory in the Institute of Aviation and the experimental investigations of crack resistance properties of laminates made of unidirectional prepreg MTM 46 were performed. Consistent results were obtained and the Paris law for II cracking mode was determined.

PL

W świetle braku dostępnych unormowanych metod zaprezentowano procedurę eksperymentalnego badania zmęczeniowego rozwoju delaminacji w warunkach II sposobu pękania. Wyróżniającą cechą zaproponowanego algorytmu jest wyznaczanie długości pęknięcia za pomocą podatności badanej próbki. Pozwala to na wyeliminowanie konieczności prowadzenia obserwacji, zastępując ją wykonaniem kalibracji podatności po zakończeniu testu. Opisana została krok po kroku metodologia, wykorzystująca zginanie trójpunktowe próbki z rozwarstwieniem (ENF), jak również przedstawione zostały obliczenia prowadzące do wyznaczenia zależności szybkości wzrostu delaminacji od wartości współczynnika uwalniania energii w postaci prawa Parisa. Metoda została wdrożona w Laboratorium Badań Kompozytów w Instytucie Lotnictwa. Przeprowadzono badania doświadczalne odporności na pękanie laminatu wykonanego z jednokierunkowego preimpregnatu MTM 46. Uzyskano zgodne wyniki oraz wyznaczono prawo Parisa dla II sposobu pękania.

20

Development and implementation of a testing method for the characterization of interlaminar delamination propagation in laminates under fatigue mode I loading conditions

Wilk J.

Prace Instytutu Lotnictwa

|

2016

|

Nr 4 (245)

239--250

EN

With no standardized methods for experimental characterization of fatigue delamination growth in laminates available the paper presents a testing method for mode I loading conditions. The distinctive feature of the proposed method is determination of crack length based on the specimen compliance and an additional compliance calibration procedure. This approach eliminates the need of visual observations. The testing methodology, using the double cantilever beam specimen, is described step by step as well as calculations leading to obtaining the relationship between the delamination growth rate and strain energy release rate values in the form of Paris' law The method was implemented in the Composites Testing Laboratory in the Institute of Aviation and the experimental investigations of crack resistance properties of laminates made of unidirectional prepreg MTM 46 were performed. Consistent results were obtained and the Paris law for I cracking mode was determined.

PL

W świetle braku dostępnych unormowanych metod zaprezentowano procedurę eksperymentalnego badania zmęczeniowego rozwoju delaminacji w warunkach I sposobu pękania. Wyróżniającą cechą zaproponowanego algorytmu jest wyznaczanie długości pęknięcia za pomocą podatności badanej próbki oraz dodatkowo przeprowadzanej kalibracji podatności. Zaprezentowane podejście pozwala wyeliminować konieczność obserwacji długości pęknięcia podczas testu. Opisana została krok po kroku metodologia, wykorzystująca próbkę w postaci podwójnej belki wspornikowej (Double Cantilever Beam), jak również przedstawione zostały obliczenia prowadzące do wyznaczenia zależności szybkości wzrostu delaminacji od wartości współczynnika uwalniania energii w postaci prawa Parisa. Metoda została wdrożona w Laboratorium Badań Kompozytów w Instytucie Lotnictwa. Przeprowadzono badania doświadczalne odporności na pękanie laminatu wykonanego z jednokierunkowego preimpregnatu MTM 46. Uzyskano zgodne wyniki oraz wyznaczono prawo Parisa dla I sposobu pękania.