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

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

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

The effects of intumescent flame retardant and nanoclay on mechanical and thermal expansion properties of high density polyethylene composites

8th International Advances in Applied Physics and Materials Science Congress and Exhibition (APMAS) -- APR 24-30, 2018 -- Fethiye, TURKEYWOS:000481717100043In this work, ammonium polyphosphate and melamine were added as a flame retardant to the nanoclay reinforced high-density polyethylene composites. Ammonium polyphosphate and melamine were added at weight ratios of 0 wt% and 20 wt% to the polymer matrix and their proportions are changed. The addition of nanoclay was carried out at weight ratios of 2 wt% to the polymer matrix. Blending operations were performed by premixing with a mechanical stirrer and melt extrusion technique with twin screw extrusion, respectively. The samples were produced by injection molding. Tensile tests, three-point bend tests, tear tests, the Izod impact tests, and thermomechanical analysis were carried out to investigate the mechanical and thermal expansion properties. Mechanical and thermomechanical test results showed that addition of intumescent flame retardant systems and nanoclay decrease the tensile strength and coefficient of linear thermal expansion values while increasing flexural strengths slightly. However, it has been observed that the addition of additives increases the flexural modulus and density of the polymer composites.[2014FBE031]; [2018KKP014]Authors would like to thank Prof. Dr. Nazim Usta (Pamukkale University) and Dr. Ayhan Ezdesir (Petkim) for valuable contributions. This study was funded by 2014FBE031 and 2018KKP014 numbered Pamukkale University scientific research projects

Stress analysis of functionally graded rotating discs: Analytical and numerical solutions

This study deals with stress analysis of annular rotating discs made of functionally graded materials (FGMs). Elasticity modulus and density of the discs are assumed to vary radially according to a power law function, but the material is of constant Poisson's ratio. A gradient parameter n is chosen between 0 and 1.0. When n = 0, the disc becomes a homogeneous isotropic material. Tangential and radial stress distributions and displacements on the disc are investigated for various gradient parameters n by means of the diverse elasticity modulus and density by using analytical and numerical solutions. Finally, a homogenous tangential stress distribution and the lowest radial stresses along the radius of a rotating disc are approximately obtained for the gradient parameter n = 1.0 compared with the homogeneous, isotropic case n = 0. This means that a disc made of FGMs has the capability of higher angular rotations compared with the homogeneous isotropic disc. © 2011 The Chinese Society of Theoretical and Applied Mechanics and Springer-Verlag Berlin Heidelberg

Investigation of experimental research on the low velocity impact damage behavior of NCF composite plates - Complas XII

In this study an experimental investigation is performed on the impact response of non-crimp fabric composite plates at room temperature. Chopped strand mat combi is used as reinforcing material and two kinds of matrix; epoxy and polyester, are also used as resin material in the composite plates. All specimens used in experiments are manufactured by vacuum assisted resin infusion method at Atard Defence and Aerospace Advanced Technology Application Research and Development Inc. 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 initiation of damage to final perforation. Damage processes of the samples are analyzed from cross-examining load-deflection curves, energy profiling method and damaged specimens

Impact behavior of hybrid composite plates

This experimental study deals with the impact response of hybrid composite laminates. Two different hybrid composite laminates, aramid/glass and aramid/carbon, and two different stacking sequences, such as [0/0/90/90] A+ [90/90/0/0]G for AG1 and [0/90/±45]A+ [±45/90/0]G for AG2 and so on (see Table I), were chosen for impact testing. The impact energywas gradually increased until complete perforation took place, and an energy profiling method (EPM)was used to identify the perforation thresholds of composites. The damaged samples were visually inspected. The images of the several samples subjected to various impact energies were registered and used for comparison and identifying damagemechanisms. The perforation thresholds for [0/90/±45]s aramid/glass and aramid/carbon laminates were found to be approximately 5% higher than those for their counterparts with the [0/0/90/90]s stacking sequence. © 2010 Wiley Periodicals, Inc