The effects of nanoclay on mechanical properties of high density polyethylene and polypropylene materials

Polymeric materials find usage in most places in daily life. Expected features vary depending on the use of these materials. Composite material can be formed by combining one or more different materials. Physical and chemical properties of a new produced composite material can be improved with the addition of additives and fillers to polymer materials. The addition of additives and fillers improve one or more properties at the same time, despite that, it may lead to deteriorate another property. Therefore, it is necessary to investigate the mechanical and thermal properties of these produced composite structures. This study was carried out by nanoclay addition to high density polyethylene (HDPE) and polypropylene (PP) materials. Nanoclay additions were made to the polymer matrix at mass ratios of 5% and 10%. Tensile test, tear test and the Izod impact tests were performed. It has been observed that the tensile strengths of HDPE composites decreased whereas PP composites increased with respect to the pure products. Also, the tear strengths of composites decreased compared to pure products. In the Izod impact tests, all notched specimens were broken. The values of impact strength of the PP composites were not changed in the notched Izod impact tests, whereas the HDPE composites showed a decrease. © 2018 Polish Academy of Sciences Institute of Physics. All rights reserved

Thermal Elastic-Plastic Stress Analysis of Symmetric Aluminum Metal-Matrix Composite Laminated Plates and Residual Stresses under Thermal Loads Varying Linearly

This paper deals with elastic-plastic stress analysis of symmetric cross-ply [0°/90°]2 and angle-ply [300/-30°] 2, [45°/-45°]2, [60°/-60°]2 aluminum metal-matrix laminated plates under thermal loads varying linearly along the thickness. The temperature is T0 at the upper and lower surfaces, respectively. The solution is performed for satisfying thermal elastic-plastic stress-strain relations and boundary conditions for small plastic deformations. Tsai-Hill Criterion is used as a yield criterion. Residual stresses distributions along the thickness of the plates are obtained. All the residual stress components are in static balance with respect to middle plane of the laminates since they are symmetric in opposite signs. The magnitude of the residual stress components is the highest at the upper and lower surfaces

Thermal elastic-plastic stress analysis of steel woven reinforced aluminum metal-matrix composite laminated plates

In this study, an elastic-plastic stress analysis is carried out on symmetric cross-ply [0°|90°]2 and angle-ply [30°|-30°]2, [45°|-45°]2, [60°|-60°]2 steel woven reinforced aluminum metal-matrix laminated plates under thermal loads varying linearly along the thickness. Laminated composite plates are simply supported and subjected to linear temperature change through the thickness as T0 at the upper and lower surfaces and T at the middle plane, respectively. An analytical solution is performed for satisfying thermal elastic-plastic stress-strain relations and boundary conditions for small plastic deformations. The composite materials are assumed to be linearly hardening. The Tsai-Hill criterion is used as a yield criterion. Plastic and residual stress distributions along the thickness of the plates are obtained. Plastic and residual stress components, (?x)p, (?y)p and (?x)r, (?y)r, have some magnitude but (?xy)p and (?xy) r are zero for all stacking sequences. All the residual stress components are in static balance with respect to the middle plane of the laminates since they are symmetric in opposite signs. The magnitude of the residual stress components is the highest at the upper and lower surfaces

THE EFFECTS OF ASPECT RATIO AND INITIAL IMPERFECTION SHAPE ON THE UNIAXIAL PLATE STRENGTH

This study is concerned with the imperfection and aspect-ratio sensitivity of the uniaxial strength of rectangular steel plates. To investigate the imperfection and aspect ratio sensitivity of the uniaxial strength of rectangular plates, over 90 different plate problems have been modelled and solved by using the user-element in ANSYS 5.0 which is a commercial finite element package. The user-element which is offered by ANSYS 5.0 as an extension of the element library, is used to implement subroutines written for analysing large deflection elastic-perfectlyplastic material behaviour of plates by using finite element method. The results obtained for each plate problem have been presented in figures. The maximum average strength of plates have been obtained for the different aspect ratios, the initial geometric imperfection modes and the complex initial geometric imperfections, achieved by combination of these modes. The levels of initial geometric imperfections are assumed as found in the literature. The effects of complex initial geometric imperfections and aspect ratios on plate strength for various modes have been determined. The combination of initial imperfection modes creates new geometrical imperfections and magnitudes, generally higher than previous values. These factors are shown to effect the plate by reducing its strength. The results obtained can help to design the rectangular plates and plated structures under uniaxial compression

Elastic-plastic and residual stress analysis of a thermoplastic composite hollow disc under internal pressures

This article deals with the elastic-plastic stress analysis of a thin thermoplastic composite disc under internal pressures. An analytical solution is performed for satisfying elastic-plastic stress-strain relations and boundary conditions for small plastic deformations. Because of the material properties, the composite disc is assumed to be elastic-perfectly plastic, and the Tsai-Hill Criterion is used as a yield criterion. Elastic-plastic and residual stress distributions are obtained from the inner radius to the outer radius, and they are presented in tables and figures. All radial stresses ?r are compressive, and they are highest at the point where the plastic deformation begins. All tangential stresses ?? are tensile, and they are highest at the inner radius. The magnitude of tangential residual stresses is higher than that of the radial residual stresses, and it changes nonlinearly from the inner radius to the outer radius. © 2005 Sage Publications

Temperature Effects on Hybrid Composite Plates Under Impact Loads

In this work, impact responses of carbon-glass fiber/epoxy (hybrid) composites were investigated under various temperatures and increasing impact energies. The increasing impact energies were applied to the specimens at various temperatures as -20, 0, 20 and 40 oC until perforation took place of specimens. Those specimens are composed by two types of fiber orientation with eight laminates hybrid composites. An Energy profiling diagram, used for showing the relationship between impact and absorbed energy, has been used to obtain penetration and perforation thresholds of hybrid composites. Beside those, temperature effects on impact characteristics such as maximum contact force (Fmax), total deflection (d) and maximum contact duration (t) were also presented in figures. Finally, glass and carbon fibers exhibited more brittle characteristics at -20 oC according to other temperatures. So, perforation threshold of each hybrid composites at -20 oC was found higher than other temperatures. Keywords : Hybrid composit

Darbe Yükü Altındaki Hibrit Kompozit Plakalara Sıcaklığın Etkisi

Bu çalışmada, karbon-cam elyaf/epoksi (hibrit) kompozitlerin sıcaklık ve artan darbe enerjisi altındaki darbe davranışları incelenmiştir. Bununla ilgili olarak iki tip tabaka dizilim açısına sahip, 8 tabakalı hibrit kompozit numunelere -20, 0, 20 ve 40 oC sıcaklıklarında, numunelerde delinme meydana gelene kadar darbe enerjisi uygulanmıştır. Hibrit kompozitlerin saplanma ve delinme sınır değerlerinin belirlenmesinde, darbe enerjisi ve absorbe edilen enerji arasındaki ilişkiyi göstermede kullanılan enerji profili diyagramı kullanılmıştır. Bunun yanı sıra, maksimum temas kuvveti (Fmax), toplam çökme (d) ve maksimum temas süresi (t) gibi önemli darbe karakteristiklerinin sıcaklık geçişlerindeki değişimleri de sunulmuştur. Sonuç olarak, cam ve karbon fiberlerin -20 oC'de, diğer sıcaklıklara göre daha çok gevrekleştiği görülmüştür. Buna göre her iki tip hibrit kompozit için -20 oC'de meydana gelen delinme sınırı diğer sıcaklıklara göre en yüksek değerde bulunmuştur

Impact response of composite plates manufactured with stitch-bonded non-crimp glass fiber fabrics

This experimental study deals with the impact response of composite plates manufactured with stitchbonded non-crimp glass fiber fabrics. Three kinds of fabrics - biaxial, triaxial, and quadraxial - are used as reinforcing material. Polyester resin is used as a matrix material in the composition of composite plates. An instrumented drop weight impact testing machine, Instron- Dynatup 9250 HV, is used for impact testing. Impact tests are performed under various impact energies, ranging from damage initiation to final perforation. An energy profiling method, showing the relation between impact energy and absorbed energy, was used together with load-deflection curves to determine the penetration and perforation thresholds of those composites. The failure processes of damaged specimens for different impact energies were evaluated by comparing load-deflection curves and images of damaged samples taken from the impacted and non-impacted sides. All types of composites have obvious penetration and perforation thresholds. The perforation threshold of triaxial/polyester composite is approximately 27% and 22% higher than that of the quadraxial and biaxial/polyester composites, respectively

Experimental investigation of buckling loads of glass/epoxy composites modified with nanoparticles

In this study, the effects of the carbon nanotubes and nanoclay particles on strength and load carrying capabilities of modified E-glass/epoxy composite plates are determined experimentally. The composite plates are modified with 0% (neat), 0.5% particle weight fractions based on the weight of composites, such as multi-walled carbon nanotubes and nanoclay. Aside from the effects of the nanoparticles, also the effects of fiber orientations such as (0?, 30?, 45?, 90?) on strength and load carrying capabilities of composite plates are determined experimentally. The addition of 0.5 wt% multi wall carbon nanotubes and nanoclay particles to composites increases the critical buckling load by almost 30% and 12%, respectively. © 2019 Polish Academy of Sciences. All rights reserved