Identification of Glass Alloy Elastic Constants Using Rod Samples

2016 ◽  
Vol 827 ◽  
pp. 352-355
Author(s):  
Karel Vítek

The methodology, used for determining the structure material elastic constants, is based on mechanical tests, being mostly tensile ones, applied on partially loaded specimens. There be can glass materials used as different alloy elements, therefore the glass elastic constants can vary considerably. However, using classic glass tensile specimens for tensile tests can be problematic, due to their production and implementation of tensile tests. Experimental methods for identifying the glass Young's modulus of elasticity and Poisson's ratio are based on a comparison of the displacement measurements applied on the glass beam, or curved rod, samples, combined with their displacements calculation.

Author(s):  
Jose Daniel D. Melo ◽  
Jeffrey T. Fong

In composite structural design, a fundamental requirement is to furnish the designer with a set of elastic constants. For example, to design for a given temperature a laminate consisting of transversely isotropic fiber-reinforced laminae, we need five independent elastic constants of each lamina of interest, namely, E1, E2, ν12, G12, and ν23. At present, there exist seven tests, two of mechanical-lamina, two of thermal-expansion-lamina, and three of thermal-expansion-laminate types, to accomplish this task. It is known in the literature that the mechanical tests are capable of measuring E1, E2, and ν12, whereas the two thermal-expansion-lamina tests will measure α1 and α2, and the three thermal-expansion-laminate tests yield an over-determined system of three simultaneous equations of the remaining two unknown elastic constants, G12 and ν23. In this paper, we propose a new approach to determining those five elastic constants with uncertainty bounds using the extra information obtainable from an over-determined system. The approach takes advantage of the classical theory of error propagation for which variance formulas were derived to estimate standard deviations of some of our five elastic constants. To illustrate this approach, we apply it to a set of experimental data on PEEK/IM7 unidirectional lamina. The experiment consists of the following tests: Two tensile tests with four samples of unidirectional specimens to measure E1, E2 and ν12; two thermal-expansion-lamina tests for coefficients (α1 and α2) each using four [(0)32]T unidirectional specimens; and three thermal-expansion-laminate tests on four samples of [(+30/−30)8]s laminates. The results of our new approach are compared with those of a similar but more ad hoc approach that has appeared in the literature. The potential of applying this new methodology to the creation of a composite material elastic property database with uncertainty estimation and to the reliability analysis of composite structure is discussed.


Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.


2014 ◽  
Vol 1025-1026 ◽  
pp. 543-546
Author(s):  
Juliana Cortez Barbosa ◽  
Anderson Luiz da Silva Michelon ◽  
Elen Aparecida Martines Morales ◽  
Cristiane Inácio de Campos ◽  
André Luis Christoforo ◽  
...  

The aim of this research was to produce three-layer Medium Density Particleboard (MDP), with the addition of impregnated paper, in the inner layer, in proportions of 1; 5 and 20%. In this study, MDP was composed with particles of small size in outer layers, and larger particles in internal layer. After panel manufacturing, physical and mechanical tests based on Brazilian Code ABNT NBR 14.810 were carried out to determine moisture content; density; thickness swelling; water absorption; modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending and internal adhesion. Test results were compared to commercial panels, produced with 100% Eucalyptus, considering the requirements specified by Brazilian Code. Properties presented values close to normative specifications, indicating positively the possibility of production of MDP using addition of waste paper impregnated.


2015 ◽  
Vol 732 ◽  
pp. 161-164 ◽  
Author(s):  
Jan Vesely ◽  
Lukas Horny ◽  
Hynek Chlup ◽  
Milos Beran ◽  
Milan Krajicek ◽  
...  

The effects of the polyvinyl alcohol (PVA) concentration on mechanical properties of hydrogels based on blends of native or denatured collagen / PVA were examined. Blends of PVA with collagen were obtained by mixing the solutions in different ratios, using glycerol as a plasticizer. The solutions were cast on polystyrene plates and the solvent was allowed to evaporate at room temperature. Uniaxial tensile tests were performed in order to obtain the initial modulus of elasticity (up to deformation 0.1), the ultimate tensile stress and the deformation at failure of the material in the water-saturated hydrogel form. It was found that the material was elastic and the addition of PVA helped to enhance both the ultimate tensile stress and modulus of elasticity of the films. Samples prepared from denaturated collagen showed the higher ultimate tensile stress and the deformation at failure in comparison with those prepared from native collagen. The results suggest that we could expect successful application of the collagen/PVA biomaterial for tissue engineering.


2020 ◽  
Vol 70 (3) ◽  
pp. 370-377
Author(s):  
Cristian Grecca Turkot ◽  
Roy Daniel Seale ◽  
Edward D. Entsminger ◽  
Frederico José Nistal França ◽  
Rubin Shmulsky

Abstract The objective of this article is to evaluate the relationship between the dynamic modulus of elasticity (MOEd), which was obtained with acoustic-based nondestructive testing (NDT) methods, and static bending properties of two domestic hardwood oak species. The mechanical properties were conducted using static modulus of elasticity (MOE) and modulus of rupture (MOR) in radial and tangential directions. Mechanical tests were performed according to ASTM D143 on small clear, defect-free specimens from the two tree species: red oak (Quercus rubra) and white oak (Quercus alba). The MOEd was determined by two NDT methods and three longitudinal vibration methods based on the fast Fourier transform. The destructive strength values obtained in this study were within the expected range for these species. The MOE was best predicted by NDT methods for both species but also had a strong capability to predict MOR.


2021 ◽  
Vol 887 ◽  
pp. 116-122
Author(s):  
A.A. Bryansky ◽  
O.V. Bashkov ◽  
Daria P. Malysheva ◽  
Denis B. Solovev

The paper presents the results of the study of registered acoustic emission (AE) parameters during static deformation and damaging of polymer composite materials (PCM). Mechanical tests were done by a static tension and a static three-point bend, accompanied by an acoustic emission method. The assessment of the loading rate effect on defects formation processes was done by additional static tension test at rate equal half of recommended by the standard and static three-point bend test at rate ten times lower than that calculated by the standard. Clustering by frequency components of the recorded AE signals with a self-organizing Kohonen map was performed. The characteristics of the types of PCM structure damage by the centroids of the obtained clusters are given. Based on the clusters accumulation during mechanical tests, the stages of damage formation for static tension and static three-point bend, the loading rate effect on the process of damage formation are described.


2006 ◽  
Vol 519-521 ◽  
pp. 985-990 ◽  
Author(s):  
Ji Dong Kang ◽  
David S. Wilkinson ◽  
J. David Embury ◽  
Khalid Hussain

A number of mechanical tests and metallographic techniques have been used to investigate the mechanism of ductile fracture of AA5754 sheet. The sequence of events in the development of shear localization is clarified using in situ strain mapping on both the sample surface and through thickness direction during tensile tests. It is observed that the failure mode changes from cup-cone type to shearing with increasing Fe content in both continuous cast (CC) and direct-chill cast (DC) AA5754 sheets. However, this transition happens in CC with much lower Fe content than DC. As very little damage is found near the fracture surface, this suggests that damage may be a consequence of the shear process rather than a trigger that determines material ductility. For both CC and DC with same Fe content of 0.21%, fracture strain of CC is much lower than DC. It is postulated that this is due to the differences of particle distribution in these two materials, especially the increased fraction of stringer type structures which exist in CC material.


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.


2018 ◽  
Vol 55 (4) ◽  
pp. 488-493
Author(s):  
Loredana Santo ◽  
Fabrizio Quadrini ◽  
Denise Bellisario ◽  
Antonella Polimeni ◽  
Anna Santarsiero

The aim of this study is proposing a combination of measurements to assess the functional variability of collagen membranes used in Guided Bone Regeneration (GBR) and Guided Tissue Regeneration (GTR) techniques. As far as clinical applications are concerned, a proper qualification is critical when deciding, among commercially available collagen membranes, upon the most appropriate one for each specific clinical case. Two commercially available collagen membranes, namely Collprotect� and Jason�, were considered for the experimentation. After thickness and density measurements, the quasi-static behavior was studied for both membranes by means of conventional mechanical tests, i.e. tear and tensile tests, whereas their time-dependent behavior was evaluated by means of stress relaxation tests and dynamic mechanical analysis. Collagen membranes showed an elevated among samples variability. The variability within the same kind of membrane is of the same order of magnitude of the between membrane kinds variability. All the membranes showed strong time dependence both in stress relaxation and in dynamic mechanical tests. This fact should be taken under consideration for the membrane final application.


2018 ◽  
Vol 52 (24) ◽  
pp. 3351-3363 ◽  
Author(s):  
Alexander S Smirnov ◽  
Vladimir P Shveikin ◽  
Evgeniya O Smirnova ◽  
George A Belozerov ◽  
Anatoly V Konovalov ◽  
...  

This work deals with studying the effect of reinforcing SiC particles on the mechanical and plastic properties of a metal matrix composite with a matrix of aluminum alloy AlMg6 (the 1560 aluminum alloy according to the Russian State Standard GOST 4784−97). We assess this effect using the results of mechanical tests at the microscale and macroscale levels. The paper analyzes the fracture mechanism at the microlevel under tensile and compressive stress conditions, as well as the type of contact between the composite constituents. The experimental results obtained for the metal matrix composite are compared with analogous experimental data for the AlMg6 alloy and a compacted material made from the AlMg6 alloy (a compacted powder without addition of SiC reinforcing particles). The studied compacted materials were not previously subjected to extrusion. The tests show a decisive influence of the reinforcing particles on the plastic and mechanical properties of the AlMg6/10% SiC metal matrix composite under compression and tension. For example, the addition of silicon carbide increased the initial yield stress of the compacted material by 26% under tensile tests, and the percentage elongation after fracture was increased up to 1.1%, while it amounted to 0.02% for the compacted material without addition of silicon carbide. Under compression, on the contrary, the addition of silicon carbide degraded plastic properties. As a result, the percentage compression before cracking was 28.4% and 57.9% for the compacted materials with and without addition of silicon carbide, respectively.


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