Effect of Particle Size on Fracture Toughness of Spherical-Silica Particle Filled Epoxy Composites

2005 ◽  
Vol 297-300 ◽  
pp. 207-212 ◽  
Author(s):  
Soon Chul Kwon ◽  
Tadaharu Adachi ◽  
Wakako Araki ◽  
Akihiko Yamaji
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Epoxy Resin ◽  
Small Particle ◽  
Volume Fraction ◽  
Silica Particles ◽  
Bending Test ◽  
High Fracture Toughness ◽  
Particle Content ◽  
Spherical Silica

We investigated the particle size effects on the fracture toughness of epoxy resin composites reinforced with spherical-silica particles. The silica particles had different mean particle diameters of between 1.56 and 0.24µm and were filled with bisphenol A-type epoxy resin under different mixture ratios of small and large particles and a constant volume fraction for all particles of 0.30. As the content with the added smaller particle increased, the viscosity of each composite before curing remarkably increased. We conducted the single edge notched bending test (SENB) to measure the mode I fracture toughness of each composite. The fracture surface with the small particle content exhibited more rough areas than the surface with larger particles. The fracture toughness increased below the small particle content of 0.8 and saturated above it. Therefore, near the small particle content of 0.8, the composite had a relatively low viscosity and a high fracture toughness.

Effect of particle size on the fracture toughness of epoxy resin filled with spherical silica

Polymer ◽  
1992 ◽  
Vol 33 (16) ◽  
pp. 3415-3426 ◽  
Author(s):  
Yoshinobu Nakamura ◽  
Miho Yamaguchi ◽  
Masayoshi Okubo ◽  
Tsunetaka Matsumoto
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Epoxy Resin ◽  
Spherical Silica ◽  
Effect Of Particle Size

Effect of particle size on fracture toughness of epoxy resin filled with angular-shaped silica

Polymer ◽  
1991 ◽  
Vol 32 (12) ◽  
pp. 2221-2229 ◽  
Author(s):  
Yoshinobu Nakamura ◽  
Miho Yamaguchi ◽  
Akiko Kitayama ◽  
Masayoshi Okubo ◽  
Tsunetaka Matsumoto
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Epoxy Resin ◽  
Effect Of Particle Size

Effects of Fly Ash Particle Sizes on the Compressive Strength and Fracture Toughness of High Performance Concrete

2011 ◽  
Vol 284-286 ◽  
pp. 984-988
Author(s):  
An Shun Cheng ◽  
Yue Lin Huang ◽  
Chung Ho Huang ◽  
Tsong Yen
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Bending Test ◽  
Strength Development ◽  
Particle Sizes

The study aims to research the effect of the particle size of fly ash on the compressive strength and fracture toughness of high performance concrete (HPC). In all HPC mixtures, the water-to-binder ratio selected is 0.35; the cement replacement ratios includes 0%, 10% and 20%; the particle sizes of fly ash have three types of passing through sieves No. 175, No. 250 and No. 325. Three-point-bending test was adopted to measure the load-deflection relations and the maximum loads to determine the fracture energy (GF) and the critical stress intensity factor (KSIC). Test results show that adding fly ash in HPC apparently enhances the late age strengths of HPC either for replacement ratio of 10% or 20%, in which the concrete with 10% fly ash shows the higher effect. In addition, the smaller the particle size is the better the late age concrete strength will be. The HPC with the finer fly ash can have higher strength development and the values of GF and KSIC due to the facts of better filling effect and pozzolanic reaction. At late age, the GF and KSIC values of concrete with 10% fly ash are all higher than those with 20% fly ash.

scholarly journals Asymmetric flux models for particle-size segregation in granular avalanches

2014 ◽  
Vol 757 ◽  
pp. 297-329 ◽  
Author(s):  
P. Gajjar ◽  
J. M. N. T. Gray
Keyword(s):  
Particle Size ◽  
Small Particle ◽  
Volume Fraction ◽  
Free Surface Flows ◽  
Two Dimensions ◽  
Combined Processes ◽  
Maximum Point ◽  
Size Segregation ◽  
Flux Function ◽  
Large Particles

AbstractParticle-size segregation commonly occurs in both wet and dry granular free-surface flows through the combined processes of kinetic sieving and squeeze expulsion. As the granular material is sheared downslope, the particle matrix dilates slightly and small grains tend to percolate down through the gaps, because they are more likely than the large grains to fit into the available space. Larger particles are then levered upwards in order to maintain an almost uniform solids volume fraction through the depth. Recent experimental observations suggest that a single small particle can percolate downwards through a matrix of large particles faster than a large particle can be levered upwards through a matrix of fines. In this paper, this effect is modelled by using a flux function that is asymmetric about its maximum point, differing from the symmetric quadratic form used in recent models of particle-size segregation. For illustration, a cubic flux function is examined in this paper, which can be either a convex or a non-convex function of the small-particle concentration. The method of characteristics is used to derive exact steady-state solutions for non-diffuse segregation in two dimensions, with an inflow concentration that is (i) homogeneous and (ii) normally graded, with small particles above the large. As well as generating shocks and expansion fans, the new asymmetric flux function generates semi-shocks, which have characteristics intersecting with the shock just from one side. In the absence of diffusive remixing, these can significantly enhance the distance over which complete segregation occurs.

Effect of particle size on impact properties of epoxy resin filled with angular shaped silica particles

Polymer ◽  
1991 ◽  
Vol 32 (16) ◽  
pp. 2976-2979 ◽  
Author(s):  
Yoshinobu Nakamura ◽  
Miho Yamaguchi ◽  
Masayoshi Okubo ◽  
Tsunetaka Matsumoto
Keyword(s):  
Particle Size ◽  
Epoxy Resin ◽  
Silica Particles ◽  
Impact Properties ◽  
Effect Of Particle Size

Effect of composition on the tensile properties and fracture toughness of A7N01S-T5 aluminum alloys welded joints

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744041
Author(s):  
Yali Liu ◽  
Guoqing Gou ◽  
Jia Chen ◽  
Hui Chen ◽  
Wanjng Wang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Welded Joints ◽  
Volume Fraction ◽  
Welding Process ◽  
Single Pulse ◽  
High Fracture Toughness ◽  
Chemical Compositions ◽  
High Fracture ◽  
Fine Grain ◽  
Backscattered Electron

In this paper, welded joints of four types of A7N01S-T5 aluminum alloy with different chemical compositions were investigated. The welding process was under 70% environmental humidity conditions at 10[Formula: see text]C with single-pulse GMAW welding technology. The strength and fracture toughness of the four types of samples were tested, and the microstructures were investigated by micro-X-ray fluorescence (SR-LXRF) technology and backscattered electron diffraction (EBSD) technology. The results showed that the #2 alloy that is composed of Zn: 4.59 wt.%, Mg: 1.56 wt.% Mn: 0.22 wt.%, Cr: 0.14 wt.%, Zr: 0.01 wt.% and Ti: 0.027 wt.% had the best combination of tensile strength and elongation, with the values of 302.35 MPa and 3.74%, respectively. The better result for the combination of the strength and elongation was mainly determined by the volume fraction and size. The fine grain size and compositions played important roles to obtain high fracture toughness.

Mechanical Properties of GFRP Laminates Manufactured by Process Combined with Wet Lay-Up and Vacuum Curing

2006 ◽  
Vol 306-308 ◽  
pp. 845-850 ◽  
Author(s):  
Joong-Suk Kook ◽  
Tadaharu Adachi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Manufacturing Process ◽  
Volume Fraction ◽  
Optical Microscope ◽  
Bending Test ◽  
Complicated Structure ◽  
Structural Shape ◽  
Volume Fractions

In this study, a manufacturing process for glass fiber reinforced plastics (GFRP) laminates was developed to improve volume fraction of fibers and mechanical properties. The manufacturing process is combination with wet lay-up and vacuum curing under atmosphere pressure for production of large and complicated structure as a leisure boat and so on. Several kinds of GFRP laminates were produced to consider optimum conditions of the process from viewpoint of volume fraction of fibers and mechanical properties. Volume fractions of fibers in GFRP laminates were measured and cross sections were observed by an optical microscope. The volume fraction in the GFRP laminate made by the suggested method was improved to 41 %, although the one made by conventional wet lay-up method was 17.7 %. Because a lot of large voids included in the laminates were drastically decreased due to the methods. For each laminate, three-point bending test was performed to measure elastic modulus and fracture toughness. Elastic modulus was improved from 5.39 GPa to 8.91 GPa with high volume fractions of fibers. Fracture toughness was improved from 8.19 MPa m1/2 to 16.6 MPa m1/2. Therefore, it was obtained that the method combined with wet lay-up and vacuum curing is easy process for manufacturing large and complicated structure to improve excellent mechanical properties and accuracy of structural shape.

Study of Aggregate Size Effect on Fracture Toughness of Petreous Macrocomposites (Concrete)

2010 ◽  
Vol 636-637 ◽  
pp. 1342-1348 ◽  
Author(s):  
Ana S. Marques ◽  
Pedro M. Amaral ◽  
Luís Guerra Rosa ◽  
Jorge Cruz Fernandes
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Aggregate Size ◽  
Ceramic Materials ◽  
Bending Test ◽  
Aggregate Particle ◽  
Linear Elastic ◽  
Rock Aggregate ◽  
Elastic Fracture ◽  
Fractographic Examination

The present study investigates the effect of rock aggregate size on the fracture toughness of a petreous macrocomposite material (concrete). The effect of aggregate size on the fracture properties of concrete was studied by analysing the fracture toughness KIC results obtained using single edge notched beam (SENB) specimens submitted to 4-point bending test. The results were obtained according to the methodology proposed by Srawley and Gross for monolithic ceramic materials. Additionally, the effect of aggregate size has been analysed by performing fractographic examination of unnotched beam specimens also submitted to 4-point bending test. KIc values obtained via linear elastic fracture mechanics (LEFM) theory applied to the fractographic data were comparable to those obtained by SENB method. The obtained results show that the fracture toughness of concrete depends on the aggregate particle size, although KIC is not linearly related with the particle size. Fracture behaviour depends on the interaction between the used mortar (a mixture of portland cement with sand and water) and the different rock (aggregate) particle sizes. This kind of studies allows further extending the knowledge on the failure mechanisms of concrete, which permits to improve the characteristics of these macrocomposite materials by understanding the effects related to the modification of their structure.

Controlling Factors of the Particle Size of Spherical Silica Synthesized by Wet and Dry Processes

2021 ◽  
Vol 6 (7) ◽  
pp. 118-121
Author(s):  
Keiji Saiki ◽  
Toshihiro Ishikawa
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Silica Particles ◽  
Controlling Factors ◽  
Dry Process ◽  
Wet Process ◽  
Spherical Silica ◽  
Wide Range ◽  
Spherical Silica Particles ◽  
Trimethoxy Silane

We clarified the controlling factors of the particle size of the amorphous silica synthesized by wet and dry processes. In the wet process using methyl-trimethoxy-silane as a starting monomer, the obtained particle size can be easily controlled by changing the reaction time appropriately. However, to obtain larger particles, a relatively long time is needed. After the condensation reaction was conducted for 50h, the silica particles (D50: 3μm) were synthesized by calcination at 550oC in air. To synthesize larger silica particles, we used silica-seed particles (8μm) to obtain very large spherical silica particles (D50: 20μm). Thus, although the wet process needs a relatively long reaction time, it is very useful for synthesizing spherical silica particles with a wide range of particle size. In the dry process, we used methyl-trimethoxy-silane (MTMS), tetra-ethoxy-silane (TEOS), and octamethyl-cyclotetrasiloxane (OMCTSO) as the starting materials. In this process, the size of the silica particles was dominated by the molecular structure of the monomer, in particular, the number of silicon atoms contained in the monomer and the bulkiness of the substituent group. The largest silica particles were synthesized from OMCTSO, which contains the largest number of silicon atoms.

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