scholarly journals Adhesion Improvement between PE and PA in Multilayer Rotational Molding

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 331
Author(s):  
Jan Sezemský ◽  
Petr Špatenka
Keyword(s):  
Multilayer Structure ◽  
Joint Strength ◽  
Peel Strength ◽  
Mechanical Tests ◽  
Bending Test ◽  
Plasma Modification ◽  
Rotational Molding ◽  
Untreated Sample ◽  
Mechanical Adhesion ◽  
Polyethylene Powder

The aim of this study is to investigate a multilayer structure made of polyethylene and polyamide by rotational molding. Due to the different polarity of these polymers, it is difficult to ensure enough adhesion between created layers. Two methods leading to improve adhesion are introduced. Plasma modification of polyethylene powder, after which new functional groups are bound to the treated surface, may enhance specific adhesion by forming hydrogen bonds with-CONH groups of polyamide. Different strategies of adding material to the mold give rise to complicated interlayer which increases joint strength by mechanism of the mechanical adhesion. Mechanical tests show a significant improvement of joint strength, where treated samples reached two-fold values of peel strength (7.657 ± 1.024 N∙mm−1) against the untreated sample (3.662 ± 0.430 N∙mm−1). During bending test, delamination occurred only in samples that were made of the untreated polyethylene. Adding polyamide during the melting stage of polyethylene powder in rotomolding resulted in the formation of entanglements which improve the peel strength almost eight times in comparison with the sample where the polyethylene was left to completely melt and create smooth interlayer surface.

scholarly journals Processing of Al2O3-AlN Ceramics and Their Structural, Mechanical, and Tribological Characterization

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6055
Author(s):  
Dheeraj Varanasi ◽  
Monika Furkó ◽  
Katalin Balázsi ◽  
Csaba Balázsi
Keyword(s):  
Mechanical Properties ◽  
Aluminum Nitride ◽  
Hot Isostatic Pressing ◽  
Xrd Analysis ◽  
Mechanical Tests ◽  
Oxidation Time ◽  
Bending Test ◽  
Coarse Powder ◽  
Powder Particles ◽  
Tribological Characterization

The aim of this study is to present a novel, lower sintering temperature preparation, processing, structural, mechanical, and tribological testing of the AlN-Al2O3 ceramics. The precursor powder of AlN was subjected to oxidation in ambient environment at 900 °C for 3, 10, and 20 h, respectively. These oxidized powders were characterized by SEM and XRD to reveal their morphology, phase, and crystal structure. The SEM results showed coarse powder particles and the presence of aluminum oxide (Al2O3) phase at the surface of aluminum nitride (AlN). The XRD analysis has shown increasing aluminum-oxy-nitride conversion of aluminum nitride as the holding time of oxidation increased. The highest percentage of conversion of AlN powder to AlN-Al2O3 was observed after 10 h. Simultaneously the powders were compacted and sintered using the hot isostatic pressing (HIP) under inert environment (N2 gas) at 1700 °C, 20 MPa for 5 h. This led to the compaction and increase in density of the final samples. Mechanical tests, such as bending test and tribology tests, were carried out on the samples. The mechanical properties of the samples were observed to improve in the oxidized samples compared to the precursor AlN. Moreover, applying longer oxidation time, the mechanical properties of the sintered samples enhanced significantly. Optimum qualitative (microstructure, oxide percentage) and quantitative (tribology, hardness, and bending tests) properties were observed in samples with 10-h oxidation time.

scholarly journals Study of dependence between microstructure and chemical composition of A32, D32, E32 grades steels at bending tests

2019 ◽  
Vol 75 (1) ◽  
pp. 57-67
Author(s):  
L. A. Ryabicheva ◽  
R. E. Velikotskii
Keyword(s):  
Tensile Strength ◽  
Science Studies ◽  
Product Yield ◽  
Negative Influence ◽  
Mechanical Tests ◽  
Bending Test ◽  
Carbon Equivalent ◽  
Metal Science ◽  
Steel Rolling ◽  
Bending Tests

Meeting the high requirements to the whole complex of mechanical characteristics is the main criteria of reliability and long service life of shipbuilding steels. To determine them it is necessary to apply modern methodologies of metal science analysis. Revelation of regularity of influence of alloying, carbon equivalent, microstructure and production technology on results of bending test of low-alloyed grades А32, D32, Е32 shipbuilding steels was the purpose of the study. Production of steel, rolling, thermal treatment, mechanical tests and metal science studies of the low-alloyed shipbuilding steels was made in Alchevsk steel-works. A quantity estimation of the D32 grade sheets microstructure was made as a result of studies, having both satisfactory and not satisfactory results of bending tests. It was determined, that stitch oxides have the most negative influence on the results of bending tests for both hot-rolled and normalized sheets. Sheets with not satisfactory results of bending tests differ from those, which passed the tests by higher value of streakiness points, particular of perlite, and in normalized condition – by higher value of Widmanstatten pattern. Sheets, which did not passed the tests, have yield strength by 5–25 MPa and tensile strength by 14–39 MPa higher, while the tensile strength was by 1.2–4.8% lower. For stable yield in bending tests within 98–100% it is necessary the tensile strength level to be not less than 30%. It is reasonably all the sheets of 10–20 mm thick out of heats with carbon equivalent higher 0.54% to subject compulsory normalization. Further increase of the sheets product yield can be achieved by decreasing of phosphor mass share and increasing of general steel purity, first of all, by decreasing of oxide inclusions

scholarly journals Investigation of Interlaminar Defects and their Influence on Interlaminar Strength

1996 ◽  
Vol 5 (4) ◽  
pp. 096369359600500
Author(s):  
J Ziao ◽  
J Tao
Keyword(s):  
Tensile Strength ◽  
Large Scale ◽  
Peel Strength ◽  
Test Method ◽  
Bending Test ◽  
Four Point Bending ◽  
Transverse Tensile ◽  
Interlaminar Shear ◽  
Transverse Tensile Strength ◽  
Set Up

In this paper, we directed our attention to the interlaminar defects and their influence on the interlaminar strengths. With the aid of a S-570 scanning electron microscope, the morphology and distribution of interlaminar defects were inspected and documented. According to their shape, size and cause of formation, the defects were classified into five types: flakiness void, irregular shaped debond, local imperfectly cured resin, debond in two multi-directional plies, and inhomogeneous fibers and the large scale debond by these fibers. The cause of defects formation was discussed by analyzing the manufacturing process of composites. The influence of defects on the interlaminar strength and its mechanism was analyzed experimentally and theoretically. The results indicate that these defects, with different effects, decrease the interlaminar strength because they form interlaminar cracks, and the interlaminar shear strength is less affected than interlaminar tensile strength, which is measured according to GB4944 test method. To comprehend defects distribution effect, a four-point-bending test method was introduced to measure the interlaminar peel strength, and a discussion was made on the correlation between the interlaminar tensile strength, interlaminar peel strength and in-plane transverse tensile strength. Finally the concept of interlaminar defect coefficient, which can be used to characterize the defects, was set up and the formula to calculate it was proposed.

scholarly journals Nonthermal plasma modification of polypropylene fibres for cementitious composites

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Tomáš Morávek ◽  
Monika Fialová ◽  
Daniel Kopkáně ◽  
Jozef Ráheľ ◽  
Pavel Sťahel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Plasma Treatment ◽  
Nonthermal Plasma ◽  
Bending Test ◽  
Plasma Modification ◽  
Surface Barrier ◽  
Polypropylene Fibres ◽  
Temperature Plasma ◽  
Concrete Matrix

AbstractThe plasma treatment of polypropylene fibres used as concrete admixtures for improving its mechanical properties is the focus of this research paper. A plasma treatment was conducted in a low-temperature plasma environment at atmospheric pressure in a DCSBD (Diffuse Coplanar Surface Barrier Discharge). The degree of hydrophilicity caused by the plasma treatment was determined by measuring the rate of penetration of water into the porous media, commonly referred to as the Washburn method. The influence of the addition of PP (polypropylene) fibres to the concrete matrix was investigated using a three point bending test which determined the flexural strength of concrete samples. Our experiments demostrate that plasma improves both the wettability of PP fibres and its adhesion to the concrete matrix. The tests of flexural strength show, that even a short plasma treatment (5 s) can have a significant impact on the mechanical properties of fibre-reinforced concrete composite.

scholarly journals INFLUENCE OF HIGH-VELOCITY IMPACT PARAMETERS ON THE STRUCTURE AND PROPERTIES OF THE VT1-0 + AMG5 JOINT

2021 ◽  
pp. 28-33
Author(s):  
M. P. Korolev ◽  
E. V. Kuzmin ◽  
S. V. Kuzmin ◽  
V. I. Lysak
Keyword(s):  
Pure Aluminum ◽  
Peel Strength ◽  
Mechanical Tests ◽  
Explosion Welding ◽  
Minimal Energy ◽  
High Velocity Impact ◽  
Structure And Properties ◽  
Joint Zone ◽  
Alloy Amg5 ◽  
Melted Metal

The paper presents the results of studying the joints of VT1-0 titanium with the aluminum-magnesium alloy AMg5, obtained by explosion welding in different modes of impact. The analysis of microstructures showed that, depending on the conditions of collision, the boundary of the joint zone can have both a wave and a waveless profile. Areas of melted metal are formed even with minimal energy input, but until a certain point they do not significantly affect the strength of the joint. At relatively low values of the energy W, titanium weakly dissolves in aluminum and is present in the melted areas in the form of crushed particles. A further increase in the modes of explosion welding leads to an increase in the degree of dissolution of titanium in melts, which is accompanied by the appearance of cracks. The results of the performed mechanical tests showed that the values of the peel strength of the layers are noticeably higher and reach an equal-strength joint in comparison with the method of welding through an intermediate layer of pure aluminum. In the investigated range of welding modes, the strength of the joint increases in the energy range W = 0,85...1,1 MJ/m, and at W = 1,1 MJ/m it reaches a maximum. With a further increase in the modes of explosion welding, the strength of the joint decreases, which is associated with a change in the structure of the melted regions with the formation of brittle intermetallics in them.

scholarly journals Crushing of Double-Walled Corrugated Board and Its Influence on the Load Capacity of Various Boxes

2021 ◽  
Author(s):  
Tomasz Gajewski ◽  
Tomasz Garbowski ◽  
Natalia Staszak ◽  
Małgorzata Kuca
Keyword(s):  
Load Capacity ◽  
Shear Stiffness ◽  
Mechanical Tests ◽  
Torsional Stiffness ◽  
Bending Test ◽  
Corrugated Board ◽  
Four Point Bending ◽  
Residual Thickness ◽  
Flexographic Printing ◽  
Four Point Bending Test

As long as the non-contact digital printing is not a common standard in the corrugated packaging industry, corrugated board crushing is a real issue that affects the load capacity of the boxes. Crushing mainly occurs during the converting of corrugated board (e.g. analog flexographic printing or laminating) and is a process that cannot be avoided. However, as show in this study, it can be controlled. In this work, extended laboratory tests were carried out on the crushing of double-walled corrugated board. The influence of fully controlled crushing (with a precision: ±10 μm) in the range from 10 to 70 % on different laboratory measurements was checked. Most of the typical mechanical tests were performed e.g. edge crush test, four-point bending test, shear stiffness test, torsional stiffness test, etc. on reference and crushed specimens. The residual thickness reduction of the crushed samples was also controlled. All empirical observations and performed measurements were the basis for building an analytical model of crushed corrugated board. The proven and verified model was then used to study the crushing effect of the selected corrugated board on the efficiency of simple packages with various dimensions.

Straight versus modular nail: Analysis of mechanical properties two knee arthrodesis methods.

2020 ◽  
Author(s):  
Jerzy Białecki ◽  
Marcin Para ◽  
Andrzej Sobolewski ◽  
Maciej Kogut ◽  
Paweł Bartosz
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
Mechanical Strength ◽  
Weight Bearing ◽  
Mechanical Tests ◽  
Bending Test ◽  
Implant Design ◽  
Knee Arthrodesis ◽  
Femoral Nail ◽  
Clinical Cases

Abstract Background Complications after arthroplasty often result in irreversible disability. In some cases for the extremity to be salvaged, the permanent knee joint arthrodesis is the last-chance procedure. Modular implant design simplifies surgical technique but modularity may potentially compromise mechanical strength of an implant. Mechanical properties of the implant are particularly important in case of knee arthrodesis without bone-on-bone contact where forces during gait and weight bearing are transmitted directly through the nail. The aim of this article was to perform comparative analysis of the mechanical properties of modular nail CHARFIX2 FN, when compared to the femoral nail, used for knee arthrodesis; and to analyze the effectiveness of treatment with use of this nail based on the observations of clinical cases. Methods Comparative analysis of: the static 4-point bending test, dynamic 4-point bending test and static torsion test. All tests were performed in accordance with requirements of ASTM F 1264. A clinical analysis of 5 cases, in which CHARFIX2 FN nails were used, was also performed. Results Based on the results of mechanical tests, the strength characteristics of CHARFIX2 FN nail have been found superior and more advantageous than corresponding features of the standard femoral nail. For CHARFIX2 FN nail, the median for flexural stiffness was almost 4 times higher and for maximum torque value was almost 2 times higher when compared to the femoral nail. Observations of the clinical cases gave satisfactory results. Conclusions The obtained mechanical tests present significant differences between CHARFIX2 FN and the femoral nail in mechanical strength and, therefore, its improved stability and safety for patients during walking. It can be used for permanent knee immobilization with satisfactory clinical results. The functional outcomes and subjective measurements of pain in patients treated with CHARFIX2 FN group are satisfying.

scholarly journals A New Approach Based on Glued Multi-Ultra High Molecular Weight Polyethylene Forms to Fabricate Bone Replacement Products

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2545
Author(s):  
Tarek Dayyoub ◽  
Aleksey Maksimkin ◽  
Fedor Senatov ◽  
Sergey Kaloshkin ◽  
Natalia Anisimova ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Phenol Formaldehyde ◽  
Peel Strength ◽  
Mechanical Tests ◽  
Cortical Layer ◽  
Compressive Yield Strength ◽  
Ene Reaction ◽  
Promising Development ◽  
Ultra High Molecular Weight

Three types of glue based on thiol-ene reaction, polyvinyl alcohol (PVA)/cellulose, and phenol formaldehyde were prepared and applied on modified ultra-high molecular weight polyethylene (UHMWPE) samples grafted by cellulose. In comparison with unmodified UHMWPE samples, T-peel tests on the modified and grafted UHMWPE films showed an increase in the peel strength values for the glues based on thiol-ene reaction, PVA/cellulose, and phenol formaldehyde by 40, 29, and 41 times, respectively. The maximum peel strength value of 0.62 Kg/cm was obtained for the glue based on phenol formaldehyde. Mechanical tests for the cylindrical multi-UHMWPE forms samples, made of porous UHMWPE as a trabecular layer and an armored layer (cortical layer) that consists of bulk and UHMWPE films, indicated an improvement in the mechanical properties of these samples for all glue types, as a result of the UHMWPE films existence and the increase in the number of their layers. The maximum compressive yield strength and compressive modulus values for the armored layer (bulk and six layers of the UHMWPE films using the glue based on thiol-ene reaction) were 44.1 MPa (an increase of 17%) and 1130 MPa (an increase of 36%), respectively, in comparison with one armored layer of bulk UHMWPE. A hemocompatibility test carried out on these glues clarified that the modified UHMWPE grafted by cellulose with glues based on PVA/cellulose and thiol-ene reaction were classified as biocompatible materials. These multi-UHMWPE forms composites can be considered a promising development for joint reconstruction.

Bending and Contact Strength of Monolithic Ceramic Materials

2011 ◽  
Vol 21 (2) ◽  
pp. 293-305 ◽  
Author(s):  
Lucia Hegedűsová ◽  
Ladislav Ceniga ◽  
Ján Dusza
Keyword(s):  
Mechanical Loading ◽  
Ceramic Materials ◽  
Mechanical Tests ◽  
Bending Test ◽  
Weibull Analysis ◽  
Single Cycle ◽  
Contact Test ◽  
Four Point Bending ◽  
Four Point Bending Test

The article deals with the determination of strength of monolithic ceramic materials by mechanical tests, in bending and contact modes, simulated by a four-point bending test and single-cycle contact test using rollers or spheres, respectively. In general, the determination of strength of ceramic materials results from statistical methods, usually represented by the Weibull analysis comprising of the determination of the characteristic strength σ0 and the Weibull modulus m. Accordingly, the characteristic strength σ0,bend and σ0,cont as well as the Weibull moduli mbend and mcont, related to the four-point bending test and the single-cycle contact test using rollers, are determined, respectively. Additionally, the comparison of numerical results of σ0,bend/ σ0,cont, mbend/ mcont confirms the validity of the Fett's theory. Along with this verification and the Weibull analysis for mechanical loading by spheres, a microstructural analysis of strength-degrading defects as fraction origins is performed for the bending and contact modes which induce different types of crack. Finally, the determination of mechanical loading causing material failure and an analysis of parameters of the cracks is also presented. The mechanical tests were applied to monolithic Si3N4 and SiC ceramic materials.

Fracture Toughness of High-Performance Concrete on Three-Point Bending Notched Beams at Elevated Temperature

2010 ◽  
Vol 89-91 ◽  
pp. 159-164 ◽  
Author(s):  
Samira Djaknoun ◽  
Evariste Ouedraogo ◽  
Ali Ahmed Benyahia
Keyword(s):  
Fracture Toughness ◽  
Nuclear Power ◽  
High Performance ◽  
Applied Load ◽  
Thermal Loading ◽  
High Performance Concrete ◽  
Thermal Conditions ◽  
Mechanical Tests ◽  
Bending Test ◽  
Three Point Bending

High-performance concrete (HPC) are advanced materials used in advances applications such as tunnels or nuclear power plant in which they can be accidentally submitted to severe stress or thermal conditions. The present study deals with the material response to thermal loading conditions. The main objective of this research is the characterization of the fracture toughness under Mode I at high temperature of high performance mortars by using notched specimens in three-point bending test in accordance with the RILEM recommendations. The mechanical loading is applied to the specimens while heated at various temperatures ranging from 25 to 900°C in isothermal conditions. The maximum applied load is found to be maximum at 300°C temperature and then to decrease sharply at higher temperatures. Analysis of SEM micrographs undertaken on the heated specimens after mechanical tests helps in the understanding of the material macroscopic behaviour. The evaluation of the material toughness during the hot testing is undertaken through analytical approach based on Fracture Mechanics. Lastly, the stress intensity factor as well as the energy of fracture evolves similarly versus temperature as the maximum applied load.

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