Mechanical Properties Of Glass Research Articles

Effect of glass temperature before cooling and cooling rate on residual stresses in tempering

Understanding of heat transfer and development of the temperature field in a glass during tempering is very important because it affects the quality. By numerical modeling, it is possible to study the effect of glass temperature before cooling and the values of heat transfer coefficients which determine the cooling rate and material properties on transient and residual stresses during cooling. Also, the effect of thermal and mechanical properties of glass, which are obtained experimentally, can be easily observed. In the present study, the tempering process of glass sheets with different glass thicknesses has been simulated. The paper presents modeling results, which explain the effect of the initial temperature before cooling and cooling rate on the residual and transient stresses of glass sheets of different thicknesses. The paper also shows that results can be presented independent of glass thickness by using two variables: the maximum temperature difference between surface and mid-plane during the cooling and the difference between glass transition and glass initial temperature. Because the mechanical properties of glass are experimental and are not very accurately known, the effect of their variation on residual stresses is also shown.

Glass Fiber Epoxy Matrix Composites Containing Zero and Two Dimensional Carbonaceous Nanoreinforcements

An approach to enhance the dispersion state of graphene nanoplatelets (GNPs) has been proposed by the incorporation of nanodiamond (ND) particles. The ND particles act as nanoseparators between individual graphene sheets to suppress the van der Waals interactions among individual sheets as well as GNPs. Glass fiber/epoxy composites filled with equal amount of UV ozone treated GNPs and ND particles in 0.1, 0.3, and 0.5 wt% were manufactured by vacuum compression. The effect of hybrid nanofillers on the mechanical and dielectric properties of composites were evaluated by tensile and short beam shear testing and free space dielectric measurements. The results have shown an enhancement in the mechanical properties of glass fiber/epoxy composites at lower wt% of graphene with ND particles as dispersion enhancers. The inclusion of ND with GNPs did not enhance the dielectric properties of the composites due to their small surface area and lower conductivity. POLYM. COMPOS., 39:E2056–E2063, 2018. © 2017 Society of Plastics Engineers

Mechanical performance of Nano‐Al2O3‐modified composites at cryogenic and room temperatures

Mechanical properties of fiber‐reinforced plastic composites at room temperature can be enhanced by adding nanoparticles. However, the damage mechanisms of nanocomposites at low temperatures are still not understood. In this article, different contents of nano‐Al2O3 particles were added on fiber surface by solid–liquid separation method, and vacuum‐assisted resin injection was adopted to manufacture composites laminates. A comparative study on the mechanical behavior of nano‐Al2O3‐filled composite at room and low temperatures was presented. Effect of nano‐Al2O3 particle contents (0, 0.5, 1, and 2 wt%) on the mechanical properties of glass fiber‐reinforced vinyl ester resin (GF/vinyl ester) composite laminates at different temperatures was investigated. The damage mechanism of these composite laminates in various environments was studied. The results showed that to a certain extent, nanoparticles could improve the mechanical properties of composites at 25 and −60°C. With assistance of scanning electron microscope (SEM) observation, the damage mechanisms of the composite laminates in various temperature conditions were further analyzed. POLYM. COMPOS., 39:3006–3012, 2018. © 2017 Society of Plastics Engineers

Effect of surface treatment on mechanical properties of glass fiber/stainless steel wire mesh reinforced epoxy hybrid composites

This paper investigates the effect of surface treatment for glass fiber, stainless steel wire mesh on tensile, flexural, inter-laminar shear and impact properties of glass fiber/stainless steel wire mesh reinforced epoxy hybrid composites. The glass fiber fabric is surface treated either by 1 N solution of sulfuric acid or 1 N solution of sodium hydroxide. The stainless steel wire mesh is also surface treated by either electro dissolution or sand blasting. The hybrid composites are fabricated using epoxy resin reinforced with glass fiber and fine stainless steel wire mesh by hand lay-up technique at room temperature. The hybrid composite consisting of acid treated glass fiber and sand blasted stainless steel wire mesh exhibits a good combination of tensile, flexural, inter-laminar shear and impact behavior in comparison with the composites made without any surface treatment. The fine morphological modifications made on the surface of the glass fiber and stainless steel wire mesh enhances the bonding between the resin and reinforcement which inturn improved the tensile, flexural, inter- laminar shear and impact properties.

LOAD BEARING CAPACITY OF THE GLASS RAILING ELEMENT

In this paper some basic physical and mechanical properties of glass as structural material are presented. This research is about specifically manufactured glass railing element that will be a part of a pedestrian bridge construction in Zagreb, Croatia. Load bearing capacity test of the glass railing element is conducted within the Faculty of Civil Engineering in Zagreb and obtained experimental results are discussed and compared to the ones provided by the numerical model. Taking into account the behaviour of laminated glass and results of experimental and numerical testing, glass railing element can be regarded as safe.

DTA를 통한 LAS계 투명 결정화 유리의 결정화 조건 최적화

The basic characteristics of glass are highly fragile and brittle consequences the ultimate purpose of glass manufacturing is to make a transparent glass with complex shape. In order to solve this problem, mechanical properties of glass can be increased by crystallization of its amorphous glass. However, glass-ceramics has become opaque through crystallization process due to the distracted interface of glass by precipitated particles. This study has been investigated thermal processing conditions of LAS transparent glass-ceramic by using DTA (differential thermal analysis), in order to control size of precipitated particle and then fabricate transparent glass-ceramic. DTA indicated that crystallization peak area was declined with increased nucleation temperature. Subsequently, we have been established optimum temperature for crystallization depending on the nucleation temperature. The transmission and thermal expansion were measured after crystallization, and the size of precipitated particle was identified in range of 20~100 nm by FE-SEM. In addition, by setting the optimized crystallization condition, with high transmission and low thermal expansion glass was synthesized through this experiment.

Studies on Preparation and Characterization of 45S5 Bioactive Glass Doped with (TiO2 + ZrO2) as Bioactive Ceramic Material

The aim of the present investigation was to evaluate the role of TiO2+ZrO2 in the system of 45S5 bioactive glass for improving the bioactivity as well as other physical and mechanical properties of 45S5 bioactive glass. The partial substitution of 1,2,3 and 4 mol% of mixed TiO2+ZrO2 (3:2) for SiO2 in 45S5 bioactive glass system was done by melting route at 1400°Cin a globar rod furnace in air. A comparative study on structural and mechanical properties, as well as bioactivity of the glasses, was reported. The glass properties were determined by XRD, FTIR spectrometry, SEM and the bioactivity of the glass samples were evaluated by in vitro test in simulated body fluid (SBF). Density and compressive strength of glass samples were measured. Results indicate that with the partial substitution of TiO2+ZrO2 for SiO2 in 45S5 bioactive glass system, the mechanical properties of the glasses were found to increase significantly. The glass samples exhibited higher density and compressive strength as compared to their corresponding 45S5 bioactive glass. The in vitro studies of glass samples in SBF had shown that the pH of the solution increased with increasing the time period for immersion during the initial stage of the reaction. This indicated the bioactivity of the samples had increased with increasing duration. On later stages, the decrease in pH of the solution with time had shown that the bioactivity of the samples had decreased.

Fabrication and Tensile Property Analysis of Polymer Matrix Composites of Graphite and Silicon Carbide as Fillers

In a world there is ever-increasing demand for new materials, composite materials finds the topmost spot. Here in this work an attempt has been made to study the mechanical properties of Glass and Vinyl Ester composites with and without fillers. Laminates are prepared by Hand Layup technique with changing the volume percentage of Vinyl Ester and fillers in each. The laminates prepared are subjected to tensile test and systematically analyzed to study the behaviour and variation of properties with respect to their composition. The results obtained from the tests have been documented with great detail.

Propargyl resin derived from biosynthesized oligophenols for the application of high temperature composite matrix

AbstractA novel addition‐cure‐type propargyloligophenol resin for high‐temperature usage was prepared via a two‐step process: Horseradish Peroxidase (HRP) catalyzed oxidation polymerization of phenols to oligophenols, and Williamson etherification of oligophenols to propargyloligophenols. Propargyloligophenols possess an ideal processability for composite manufacture, i.e. good solubility, low melting point (< 50 °C), and thermal curability. As shown by Differential Scanning Calorimetry (DSC), propargyloligophenol resin upon heating experiences a broad thermal exothermic peak in the range of 175–300 °C peaking at around 260 °C. The cured resin is high‐temperature resistant with an initial decomposition temperature > 400 °C and an anaerobic char yield > 60 % at 700 °C. The mechanical properties of glass fabric‐reinforced propargyloligophenol laminate were superior to those of conventional phenolic resins. The results showed that propargyloligophenol resin is a prospective polymeric matrix for high temperature composites.

Effects of alkaline conditioning and temperature on the properties of glass fiber polymer composite rebar

This article investigated long term alkaline conditioning and temperature on the physical and mechanical properties of glass fiber‐reinforced polymer (GFRP) composite rebar for structural applications. The GFRP rebar was immersed in alkaline solution (pH ≈ 13) for 23 months at 23°C, and for 24 months at 60°C. The moisture absorption was found to be 0.34% at 23°C after 23 months, and 0.76% at 60°C after 24 months. At both temperatures, moisture absorption did not reach equilibrium which was attributed to two stages non‐Fickian behavior. Glass transition temperature (Tg) of the polymer matrix of rebar that conditioned at 23°C was found to be decreased because of plasticization, whereas Tg of the rebar that conditioned at 60°C was remained greater than the Tg of control rebar due to nonplasticization effect. Shear strength was retained by 83.5% at 23°C and 80.5% at 60°C, flexural strength was retained by 81% at 23°C and 69% at 60°C, and tensile strength was retained by 91.2% at 23°C and 74.3% at 60°C. It was revealed that durability of GFRP rebar in alkaline environment was controlled by the absorbed moisture; this was because the load transfer efficiency of fiber/matrix interface is vulnerable to moisture. POLYM. COMPOS., 37:3181–3190, 2016. © 2015 Society of Plastics Engineers

Flame retardant, thermal, and mechanical properties of glass fiber/nanoclay reinforced phenol-urea-formaldehyde foam

To increase the toughness, flame retardancy, and compression strength of phenolic foams, glass fiber/nanoclay composites were prepared, and their mechanical property, cellular structure, thermal stability, and flame retardancy were investigated. The results show that the pulverization rate of phenolic foam decreases significantly by adding glass fibers and nanoclay. The impact strength of the composite foam significantly increases with increasing quantities of glass fiber and nanoclay, while the compression strength of the composite foam first increases and then decreases. The microstructure of the composite foam indicates that excessive glass fiber increases the number of open cells, while an appropriate quantity of nanoclay can control the cell size. Further, excessive clay increases the thickness of cell walls and the percentage of open cells. Nanoclay increases the thermal stability of the composite foam; this decreases the maximum heat release rate, total heat release, and total smoke release of the foam, thus reducing its fire hazards. Glass fiber and nanoclay demonstrate good synergistic effects and significantly increase the compression strength, thermal stability, and flame retardancy of the foam. Moreover, the addition of nanoclay and glass fiber–nanoclay decreases the average aperture of the cells. POLYM. COMPOS., 37:2323–2332, 2016. © 2015 Society of Plastics Engineers

Influence of particle size and interfacial interactions on the physical and mechanical properties of particle-filled myofibrillar protein gels

The mechanical properties of glass and wax particle-filled myofibrillar protein gels were characterized based on filler size and surface effects. Increases in elastic moduli were explained using established models describing particle-filled networks.

Study on Machining Mechanism of Glass Using Discrete Element Method

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

Effect of the addition of nanoclays on the water absorption and mechanical properties of glass fiber/up resin composites

Mechanical performance of composite materials must remain satisfactory during their life in service. However, composite structures such as wind blades are usually exposed to humid and severe environments, and the absorbed water can degrade the fiber–matrix interface decreasing the composite overall performance. Dual scale (nano-micro) composites can be obtained by adding nanoparticles to the polyester resin and reinforcing that nanomaterial with a glass fiber mat. These materials have good potential in the production of composite parts such as wind blades because nanoparticles dispersed in the polymer matrix could lower the water absorption of the composites and improve their performance in humid environments. However, nanosized reinforcing particles have high internal surface and therefore they tend to agglomerate and are difficult to disperse homogeneously in the polymeric matrix. Moreover, the final properties of the nanocomposites are strongly influenced by clay particles’ morphology and dispersion. In this work, the effect of the addition of pristine and organomodified nanoclays on the water absorption and mechanical properties of glass fiber/unsaturated polyester resin composites was studied. Results showed that the chemical treatments were effective in improving clay dispersion, reducing water absorption, and increasing the composites’ performance in humid environments. In addition, this work presents a procedure to use water absorption tests as means of accelerated humidity absorption tests.

Effects of hydrothermal aging on glass–fiber/polyetherimide (PEI) composites

The moisture absorption behavior and the influence of moisture on thermal and mechanical properties of glass–fiber/polyetherimide (PEI) laminates have been investigated. The laminates were exposed to hydrothermal aging at two different temperatures and high moisture rates. The properties of as-received and hydrothermally aged samples were compared. The hydrothermally aged laminates contained a large amount of moisture which caused decrease in the glass transition temperature and deterioration in mechanical properties (interlaminar shear strength, flexural modulus, bearing strength, etc.). Fractographic analysis revealed interfacial debonding as the dominant failure mechanism, indicating a strong influence of water degradation on fracture toughness results. Alterations in visco-elastic properties of glass/PEI composite which was exposed to hydrothermal aging were analyzed with the dynamic mechanical thermal analysis (DMTA) method. DMTA tests give evidence of plasticization of the PEI matrix.

ガラス短繊維強化フェノール樹脂複合材の機械特性に及ぼす成形法の影響(<小特集>M&P2009機械材料・材料加工部門技術講演会)

ガラス短繊維強化フェノール樹脂複合材の機械特性に及ぼす成形法の影響(<小特集>M&P2009機械材料・材料加工部門技術講演会)

Fabrication and mechanical properties of glass fiber‐reinforced wood plastic hybrid composites

AbstractTo fully utilize the resource in the municipal solid waste (MSW) and improve the strength and toughness of wood plastic composites, glass fiber (GF)‐reinforced wood plastic hybrid composites (GWPCs) were prepared through compounding of recycled high‐density polyethylene (HDPE) from MSW, waste wood fibers, and chopped GF. Mechanical tests of GWPCs specimens with varying amounts of GF content were carried out and the impact fractured surface of GWPCs was observed through scanning electron microscope (SEM). The tensile strength of GWPCs and the efficiency coefficient values were predicted by Kelly‐Tyson method. The results indicated that the tensile strength and impact strength of GWPCs could be improved simultaneously by adding type L chopped GF (L‐GF), and would be dropped down when type S chopped GF (S‐GF) was included. The tensile strength of GWPCs was well accordant with the experimental result. The efficiency coefficient values of S‐GF and L‐GF are −0.19 and 0.63, respectively. Inspection of SEM micrographs indicated that L‐GF had achieved full adhesion with the plastic matrix through addition of maleic anhydride‐g‐polyethylene. The main fracture modes of GWPCs included pullout of GF, broken of matrix, and interfacial debonding. Because of the synergistic effects between hybrid components in GF/wood fiber/HDPE hybrid system, a special 3D network microstructure was formed, which was the main contribution to the significant improvement in the tensile strength and impact strength of L‐GF‐reinforced hybrid composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

525 ガラス短繊維強化フェノール樹脂複合材料の機械特性に及ぼす成形法の影響(環境対応型材料の特性・評価)

525 ガラス短繊維強化フェノール樹脂複合材料の機械特性に及ぼす成形法の影響(環境対応型材料の特性・評価)

A Study of Water Absorption and Mechanical Properties of Glass Fiber/Polyester Composite Pipes — Effects of Specimen Geometry and Preparation

Ring-shaped glass fiber/polyester composite specimens cut from composite pipes with various lengths and cut edge quality were immersed into deionized water, and their water absorption was noted regularly by registering their mass gain. Monotonic ring compression tests were performed to monitor the stiffness properties during the water absorption process. Effect of specimen length and cut edge sealing with the matrix material of the pipe on the water absorption process was analyzed. Water absorption curves were fitted to the experimental data with very high correlation coefficients. Specimen types with cut edge sealing were found to absorb significantly less water than the other types, and the absorbed water showed a nonlinear monotonic decreasing tendency with specimen length. Mechanical properties were found to be only slightly affected by moisture probably because of the small amount of absorbed water.

Effect of the state of the surface layers on the strength of materials for optoelectronic and sensors devices

The goal of this work is to determine the correlation of the strength of brittle amorphous nonmetallic materials with the defective surface layers and their physical properties. The defective surface layer of materials for optoelectronic and sensors devices consists of abundant structural near-surface defects, which are displaced under action of constant load and thermal fluctuations, reducing the elasticity of the surface layer. Microcreep processes in tested materials can be described by a general equation that is known as the logarithmic microcreep equation. The applicability of this equation for tested optical materials is indicative of the generality of microcreep processes in crystalline and amorphous hard materials. For each grade of polished optical glass, a minimal residual defective layer exists. The parameters of this layer are interrelated with the mechanical properties of glass, such as microhardness and optical strain coefficient, and thermophysical properties, such as thermal diffusivity, sintering temperature, and annealing temperature. The greater are the values of these properties, the less is the concentration of disrupted interatomic bonds. Based on the test results, the corresponding equation, using the parameter E⋅a 1/2 , for determining the strength of optical silicate glass