scholarly journals Acoustic Emission and K-S Metric Entropy as Methods for Determining Mechanical Properties of Composite Materials

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 145
Author(s):  
Lesław Kyzioł ◽  
Katarzyna Panasiuk ◽  
Grzegorz Hajdukiewicz ◽  
Krzysztof Dudzik

Due to the unique properties of polymer composites, these materials are used in many industries, including shipbuilding (hulls of boats, yachts, motorboats, cutters, ship and cooling doors, pontoons and floats, torpedo tubes and missiles, protective shields, antenna masts, radar shields, and antennas, etc.). Modern measurement methods and tools allow to determine the properties of the composite material, already during its design. The article presents the use of the method of acoustic emission and Kolmogorov-Sinai (K-S) metric entropy to determine the mechanical properties of composites. The tested materials were polyester-glass laminate without additives and with a 10% content of polyester-glass waste. The changes taking place in the composite material during loading were visualized using a piezoelectric sensor used in the acoustic emission method. Thanks to the analysis of the RMS parameter (root mean square of the acoustic emission signal), it is possible to determine the range of stresses at which significant changes occur in the material in terms of its use as a construction material. In the K-S entropy method, an important measuring tool is the extensometer, namely the displacement sensor built into it. The results obtained during the static tensile test with the use of an extensometer allow them to be used to calculate the K-S metric entropy. Many materials, including composite materials, do not have a yield point. In principle, there are no methods for determining the transition of a material from elastic to plastic phase. The authors showed that, with the use of a modern testing machine and very high-quality instrumentation to record measurement data using the Kolmogorov-Sinai (K-S) metric entropy method and the acoustic emission (AE) method, it is possible to determine the material transition from elastic to plastic phase. Determining the yield strength of composite materials is extremely important information when designing a structure.

2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Zahid Iqbal Khan ◽  
Zurina Mohamad ◽  
Abdul Razak Rahmat ◽  
Unsia Habib

Lightweight and high strength composite materials are vital for unmanned aerial vehicles (UAVs) and aerospace technologies with desired characteristics. Carbon composite materials exhibit extraordinary properties for UAVs and aerospace applications. This study aimed to discover the best-prepared composition of composites material having epoxy LY-5052 and carbon fibres laminate for UAVs. Besides, to develop a low cost with high specific strength composite material for aerospace application to replace metallic alloys. In this work, the vacuum bag technique is used to prepare rectangular strips of three different ratios of carbon fibre/epoxy laminates [(40:60), (50:50) and (60:40)] to obtain the best composite in terms of properties. The thermo-mechanical and viscoelastic behaviour of composite materials were evaluated using differential scanning calorimetry (DSC), universal testing machine (UTM) and dynamic mechanical analysis (DMA). The tensile strength of epoxy LY5052 composites with 60 wt% has enhanced to 986%, and glass transition temperature (Tg) was improved from 71oC to 110oC. Overall, 60 wt% carbon fibre exhibits better thermo-mechanical properties with lightweight, which may be a future composite material for aerospace, especially UAVs technologies.


Author(s):  
B. Rajesh ◽  
M. L. S. Devakumar

The purpose of this paper is to investigate the mechanical properties of kevlar fiber and jute fiber reinforcement. Nowadays the composite materials are widely used materials. Having wide range of applications due to its light weight, high strength and low cost. These composite materials are now being explored in applications of aerospace and automotive industries. In the present work, the composite material is prepared with intermediate aramid fabric layer (Kevlar) which is high strength fiber and it is combined with jute fabric reinforced epoxy composite to increase the strength of kevlar. This composite material is tested for mechanical properties like flexural, tensile & impact strength are calculated with UTM (universal testing machine) for flexural, tensile tests and impact testing is done with impact testing machine. Through this test results the impact strength of the composite material is calculated. The energy dissipation by impact test of jute and kevlar fabric composite and strength of fibers will be analyzed by scanning electron microscopy (FESEM). Thermo gravity analysis (TGA) and differential thermal analysis (DTA) is carried out. Through these test results it can conclude that the jute can be combined with the kevlar where the impact is primary considerations like bulletproof vests, automobile bodies, tyres etc. The usage of jute in all kevlar applications will increase the strength of kevlar by reducing the usage of Kevlar and cost will be minimized.


2012 ◽  
Vol 496 ◽  
pp. 281-284
Author(s):  
Wen Wen Liu ◽  
Zhi Wang ◽  
Yun Hai Du ◽  
Xian Zhong Xu ◽  
Da Quan Liu ◽  
...  

An improved accurate speckle projection method is used for study the mechanical properties of the composite material film in the paper. A system for deformation measurement is developed with the telecentric lenses, in which such conventional lens’ disadvantages such as lens distortion and perspective error will be diminished. Experiments are performed to validate the availability and reliability of the calibration method. The system can also be used to measure the dynamic deformation and then results are also given.


2012 ◽  
pp. 189-198 ◽  
Author(s):  
Jelena Petrovic ◽  
Darko Ljubic ◽  
Marina Stamenovic ◽  
Ivana Dimic ◽  
Slavisa Putic

The significance of composite materials and their applications are mainly due to their good properties. This imposes the need for their recycling, thus extending their lifetime. Once used composite material will be disposed as a waste at the end of it service life. After recycling, this kind of waste can be used as raw materials for the production of same material, which raises their applicability. This indicates a great importance of recycling as a method of the renowal of composite materials. This study represents a contribution to the field of mechanical properties of the recycled composite materials. The tension mechanical properties (tensile strength and modulus of elasticity) of once used and disposed glass-epoxy composite material were compared before and after the recycling. The obtained results from mechanical tests confirmed that the applied recycling method was suitable for glass-epoxy composite materials. In respect to the tensile strength and modulus of elasticity it can be further assessed the possibility of use of recycled glass-epoxy composite materials.


Author(s):  
Alsaid Mazen ◽  
Ali Salamekh

In the last decades there is increasing the need to apply polymer composite materials in different industries, particularly in shipbuilding. There are developing single structures made from polymer composite materials to be used on board ships. The article focuses on technology of manufacturing slabs from polymer composite materials to carry out mechanical testing in the laboratory special standard units. Mechanical properties of polymer composite materials depend on molding technologies. There has been described a technology of sample manufacturing from polymer composite materials reinforced with glass fiber mat with fiberglass plastics. The technique of testing the specified samples for tensile strength has been considered. The sizes and shapes of the samples as well as the technological parameters of the manufacturing process have been validated, depending on the standard requirements and the technological features of the testing machine. The physical and mechanical properties of the components that make up the composite materials are considered. The sequence of stacking layers for preparation of plates from composite materials is indicated. The dimensions of the plates for cutting out finished samples are determined, depending on the method of production. The way of laying plates from composite materials has been chosen on the base of economic considerations and conditions of accessibility. The obtained results of mechanical properties can be used in solving problems of application of polymer composite materials in shipbuilding, for example, in manufacturing superstructures of some dry cargo vessels.


2021 ◽  
Vol 889 ◽  
pp. 27-31
Author(s):  
Norie A. Akeel ◽  
Vinod Kumar ◽  
Omar S. Zaroog

This research Investigates the new composite materials are fabricated of two or more materials raised. The fibers material from the sources of natural recycled materials provides certain benefits above synthetic strengthening material given that very less cost, equivalent strength, less density, and the slightest discarded difficulties. In the current experiments, silk and fiber-reinforced epoxy composite material is fabricated and the mechanical properties for the composite materials are assessed. New composite materials samples with the dissimilar fiber weight ratio were made utilizing the compression Molding processes with the pressure of 150 pa at a temperature of 80 °C. All samples were exposed to the mechanical test like a tensile test, impact loading, flexural hardness, and microscopy. The performing results are the maximum stress is 33.4MPa, elastic modulus for the new composite material is 1380 MPa, and hardness value is 20.64 Hv for the material resistance to scratch, SEM analysis of the microstructure of new composite materials with different angles of layers that are more strength use in industrial applications.


2011 ◽  
Vol 217-218 ◽  
pp. 1170-1173
Author(s):  
Wei Wei Qiao ◽  
Hui Wang ◽  
Yan Hua Zhao ◽  
Yi Xia Han

We investigate the mechanical properties of Poly Vinyl Chloride (PVC)/ acrylnitrile-butadiene-styrene copolymer (ABS) composite material with an impact testing machine,a material testing machine and other accessory devices. The result shows that the mechanical properties of PVC/ABS composite are a function of composition, the addition of ABS improved the mechanical properties of PVC/ ABS composite,the impact strength and elongation at break rise significantly with increasing ABS content in PVC/ABS composite and appears maximum value,While the tensile strength and modulus almost decrease monotonously with increasing ABS content in PVC/ABS composite.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jianxun Chen ◽  
Qingsong Wang ◽  
Jiaqi Guo ◽  
Yanbin Luo ◽  
Yao Li ◽  
...  

Firstly, I-RPT ultrasonic detector was used to test the wave velocity of karst limestone with different initial microstructure and water content. Then, RMT-150B rock testing machine and DS2-16B acoustic emission system were used to test the acoustic emission (AE) under uniaxial compression. Mechanical properties and AE characteristics were obtained during rock failure. The detailed relationship between stress-strain and AE characteristics was studied in this paper. Research results indicated the following: (1) For samples with many primary fissures and defects, wave velocity in dry state was larger than that in its natural state. From natural state to saturated state, the wave velocity tended to increase. For samples with good integrity, wave velocity increased with increasing of water content. (2) In the dry state, the samples presented tension failure. In saturated state, the samples presented tension-shear failure. For samples with cracks and good integrity, samples showed brittle failure. For samples with many corrosion pores which showed ductile damage under natural and saturated state, the spalling phenomenon was enhanced under saturated state. (3) With increasing of water content, the peak stress and AE peak reduced dramatically. In brittle failure, AE peak could be considered a sign of failure. In ductile failure, AE activity decreased gradually with the decrease of stress. (4) The mechanical properties and AE characteristics corresponding to four main fracture propagation types were also discussed.


2013 ◽  
Vol 550 ◽  
pp. 9-16
Author(s):  
Kamal Ait Tahar ◽  
R. Bahar

Currently, the composite materials make important great strides, considering their high mechanical properties. The studies relating to the conceptual, technical aspect and modeling of their mechanical behavior are more than desirable. The mechanical properties of the composite material depend on several factors as the nature of fibers, the fiber/matrix ratio, compatibility, homogeneity... In this study, we present the results of an experimental analysis of the behavior of the composite material, under a static and a dynamic loading. The composite material is composed respectively of the glass and metal fiber reinforcement. A various dimensions of the mesh are considering. The resin used is polyester Resow 55 E. The dynamic test ( Knoop test) is carried out on various specimens made up of an polyester resin RESOW 55 E reinforced with varied powder nature. It makes it possible to measure the hardness of composite materials. The analysis of the results shows clearly that the mechanical properties are strongly influenced by the dimensions of the elementary mesh of the fiber grid reinforcement. Based on experimental results, a Weibull modulus has been established for each specimen.


Author(s):  
Alsaid Mazen ◽  
Ali Salamekh

The development of modern shipbuilding requires using new structural materials, superior to traditional ones. Polymeric composite materials are among the most promising. The article studies the mechanical properties of multilayer polymer composite materials made of glass fabrics under tension and the effect of the number of layers of glass mat on the tensile strength of the material. The technology of manufacturing samples from polymer composites reinforced with fiberglass plastic is being considered. The size and shape of the samples, the technological parameters of the manufacturing process, which depend on standard requirements, and the technological features of the testing machine are substantiated. It has been stated that fiberglass is the cheapest and most common type of composite materials, which does not require special maintenance, the cost of maintenance of fiberglass structures being significantly lower than that of steel structures. The method of testing the tensile strength of the samples has been studied. For conducting experiments, samples of glass mat brand EMC-600-1250-E were used. According to the study results, the mathematical dependence of tensile strength on the number of layers was established, and the most important stages of statistical processing of test results were laid out using the Minitab 18.1 software package. A graph of the relationship between the number of layers and tensile strength is presented. For all the examined samples the ultimate strength will depend on the number of layers. The results of mechanical properties can be used in solving problems associated with the application of polymer composite materials in shipbuilding, for example, in manufacturing superstructures of dry cargo vessels.


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