Characterisation of Titanium Powder Flow, Shear and Bulk Properties Using the FT4 Powder Rheometer

2014 ◽  
Vol 1019 ◽  
pp. 218-224 ◽  
Author(s):  
Silethelwe Chikosha ◽  
Linda M. Mahlatji ◽  
Hilda K. Chikwanda
Keyword(s):  
Particle Size ◽  
Internal Friction ◽  
Fine Powder ◽  
Friction Angle ◽  
Wall Friction ◽  
Flow Shear ◽  
Coarse Powder ◽  
Bulk Properties ◽  
Angle Of Internal Friction ◽  
Powder Rheometer

In order to reliably design and operate different powder processes, an understanding of the dynamic flow, shear and bulk properties of powders is required. Generally, powders are evaluated by several techniques that determine their flow, shear and bulk properties. The techniques can include compression tests, shear tests, angle of repose, flow of powder in a funnel, tapped density and many others. In order to minimize the number of instruments required to characterise the powder and eliminate operator error, automated powder rheometers that can do most of the required tests have been developed. The FT4 powder rheometer is one of these and has found widespread use in the pharmaceutical industry. In this study, the FT4 powder rheometer was used to characterise two metallic titanium powders with different particle sizes, namely CSIR Ti-45μm (Fine Powder) and CSIR Ti +45-180μm (Coarse Powder). Their particle size, particle size distribution, bulk densities, compressibility, cohesion, flowability index, effective angle of internal friction and wall friction angle were determined. Preliminary results of the study indicated that fine powder had a lower bulk density, was more compressible and more cohesive than the coarse powder. The fine powder had a lower flowability index compared to the coarse powder for both the Jenike and Peschl classification. The varying degrees of cohesion of these powders were confirmed by the cohesion values that were higher for the fine powder. The fine powder had a lower angle of internal friction but higher wall friction angle compared to the coarse powder.

scholarly journals Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Stiffness Ratio ◽  
Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

scholarly journals A Comparative Analysis of the Flow Properties between Two Alumina-Based Dry Powders

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Milene Minniti de Campos ◽  
Maria do Carmo Ferreira
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Ceramic Powder ◽  
Morphological Characteristics ◽  
Angle Of Repose ◽  
Wall Friction ◽  
Flow Index ◽  
Alumina Powder ◽  
Flow Properties ◽  
Angle Of Internal Friction

We measured and compared the flow properties of two alumina-based powders. The alumina powder (AP) is irregularly shaped and has a smooth surface and moisture content of 0.16% (d.b.), and the ceramic powder (CP), obtained after atomization in a spray dryer, is spherical and has a rough surface and moisture content of 1.07%. We measured the Hausner ratio (HR), the static angle of repose (AoR), the flow index (FI), the angle of internal friction, and the wall's friction angle. The properties measured using aerated techniques (AoR and HR) demonstrated that AP presents true cohesiveness (and therefore a difficult flow), while CP presents some cohesiveness and its flow might be classified as half way between difficult and easy flow. Their FI values, which were obtained using a nonaerated technique, enable us to classify the alumina as cohesive and the ceramic powder as an easy-flow powder. The large mean diameter and morphological characteristics of CP reduce interparticle forces and improve flowability, in spite of the higher moisture content of their granules. The angles of internal friction and of wall friction were not significantly different when comparing the two powders.

Formulation of Seismic Passive Resistance of Retaining Wall Backfilled with c-F Soil

2012 ◽  
Vol 3 (2) ◽  
pp. 15-24 ◽  
Author(s):  
Sima Ghosh
Keyword(s):  
Retaining Wall ◽  
Pressure Coefficient ◽  
Earth Pressure ◽  
Friction Angle ◽  
Wall Friction ◽  
Unit Weight ◽  
Passive Resistance ◽  
Angle Of Internal Friction ◽  
Variation Of Parameters ◽  
Wide Range

Knowledge of passive resistance is extremely important and it is the basic data required for the design of geotechnical structures like the retaining wall moving towards the backfill, the foundations, the anchors etc. An attempt is made to develop a formulation for the evolution of seismic passive resistance of a retaining wall supporting c-F backfill using pseudo-static method. Considering a planar rupture surface, the formulation is developed in such a way so that a single critical wedge surface is generated. The variation of seismic passive earth pressure coefficient are studied for wide range of variation of parameters like angle of internal friction, angle of wall friction, cohesion, adhesion, surcharge, unit weight of the backfill material, height and seismic coefficients.

Study on the Granular Shear Strength Parameters of Dumping Site

2012 ◽  
Vol 256-259 ◽  
pp. 358-361
Author(s):  
Xiang Yun Kong ◽  
Guang Jin Wang ◽  
Xiao Chao Zhou
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Dumping Site ◽  
Size Grading

Apparent particle size grading is the important characteristic of super-high bench dumping site, and the critical factors with the impact of its stability and disaster prevention are the fragmentation distribution and shear strength parameters of granular. With the copper mine dumping site which had the feature of apparent particle size grading, the thesis carried out the study of on-site particle size investigation and indoor laboratory. The particle-size distribution law with the changing of dumping-site height was analyzed and quantitative relationship between the fragmentation distribution and shear strength parameters of granular was discussed. The research results indicated that coarse-grain contents and maximum grain size were increased significantly according to the decreasing of dumping-site height, which showed that the dumping-site had the feature of apparent particle size grading. The coarse particle content in the grain size composition and internal friction angle φ of shear strength parameters increased with the obvious increment of the distribution value B. The relationship between distribution value B and the internal friction angle φ could be expressed by exponential function curve.

scholarly journals Experimental Studies of Scale Effect on the Shear Strength of Coarse-Grained Soil

2022 ◽  
Vol 12 (1) ◽  
pp. 447
Author(s):  
Shuya Li ◽  
Tiancheng Wang ◽  
Hao Wang ◽  
Mingjie Jiang ◽  
Jungao Zhu
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Scale Effect ◽  
Friction Angle ◽  
Coarse Grained ◽  
Test Results ◽  
Maximum Particle Size ◽  
Maximum Particle ◽  
Coarse Grained Soil

Shear strength is an essential index for the evaluation of soil stability. Test results of the shear strength of scaled coarse-grained soil (CGS for short) are usually not able to accurately reflect the actual properties and behaviors of in situ CGS due to the scale effect. Therefore, this study focuses on the influence of the scale effect on the shear strength of scaled CGS, which has an important theoretical significance and application for the strength estimation of CGS in high earth-rock dam engineering. According to previous studies, the main cause of the scale effect for scaled CGS is the variation of the gradation structure as well as the maximum particle size (dmax), in which the gradation structure as a characteristic parameter can be expressed by the gradation area (S). A total of 24 groups of test soil samples with different gradations were designed by changing the maximum particle size dmax and gradation area S. Direct shear tests were conducted in this study to quantitatively explore the effect of the gradation structure and the maximum particle size on the shear strength of CGS. Test results suggest that the shear strength indexes (i.e., the cohesion and internal friction angle) of CGS present an increasing trend with the improvement of the maximum particle size dmax, and thus a logarithmic function relationship among c, φ, and dmax is presented. Both cohesion (c) and internal friction angle (φ) are negatively related to the gradation area (S) in most cases. As a result, an empirical relationship between c, φ, and S is established based on the test results. Furthermore, a new prediction model of shear strength of CGS considering the scale effect is proposed, and the accuracy of this model is verified through the test results provided by relevant literature. Finally, the applicability of this model to different types of CGS is discussed.

scholarly journals The Influence of Compaction and Water Conditions on Shear Strength and Friction Resistance between Geotextiles and Ash-Slag Mixture

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1086
Author(s):  
Andrzej Gruchot ◽  
Tymoteusz Zydroń ◽  
Agata Michalska
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Water Saturation ◽  
Friction Angle ◽  
Interaction Coefficient ◽  
Interfacial Friction ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Angle Of Internal Friction ◽  
Friction Resistance

The paper presents the results of tests of the shear strength of the ash–slag mixture taken from the landfill located in Kraków (Poland) and the interfacial friction resistance at the contact between the ash–slag mixture and woven or nonwoven geotextiles. The tests were carried out in a direct shear apparatus on samples with and without water saturation. The samples for testing were formed in the apparatus box at the optimum moisture by compacting them to IS = 0.90 and 1.00. The test results reveal that the shear strength parameters of the ash-slag mixture were large. It was stated the significant influence of the compaction, the growth of which has resulted in an increase in the angle of internal friction (from 7% to 9%) and cohesion (from 60% to 97%). Whereas the saturation of the samples reduced the shear strength parameters (from 4% to 6%, of the internal friction angle and 30% to 43% of cohesion). The values of the interfacial friction resistance at the contact between the ash–slag mixture and the geotextiles were large as well, but slightly smaller than the values of the shear strength parameters of the mixture itself. The compaction caused an increase in the angle of interfacial friction (from 1% to 5%) and adhesion (from 31% to 127%). The water-saturation of the samples caused a change in the angle of interfacial friction (from −6% to 3%) and decline in the adhesion (from 22% to 69%). Values of the interaction coefficient were about 0.8–1.0 and they tended to rise with increasing the normal stress. Higher values of this parameter were obtained in tests with water saturation and for non-woven geotextiles.

scholarly journals Microstructure and Mechanical Properties of an Advanced Nickel-Based Superalloy in the as-HIP Form

2011 ◽  
Vol 278 ◽  
pp. 265-270 ◽  
Author(s):  
J.R. May ◽  
M.C. Hardy ◽  
M.R. Bache ◽  
David D. Kaylor
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Crack Growth ◽  
Powder Particle ◽  
Size Fraction ◽  
Fine Powder ◽  
Powder Particle Size ◽  
Particle Size Fraction ◽  
Coarse Powder ◽  
Nickel Based Superalloy

This study evaluates the suitability of as-hot isostatically pressed (HIP) RR1000 for non-critical applications in aero-engine components. RR1000, an advanced powder nickel-based superalloy, was developed for disc rotor components in aero-engines. For these critical applications, the consolidated alloy powder particles are extruded to break down carbide and oxide networks, known as prior particle boundaries (PPBs), and to refine the structure into a fine grain size for isothermal forging. In this study, hot isostatically pressed compacts, made from two different powder particle size fractions have been assessed following heat treatments below and above the gamma prime solvus temperature. A microstructural evaluation shows a greater degree of PPB decoration occurs in the finer powder particle size fraction. Following a super-solvus heat treatment these PPBs pin grain boundaries of the fine powder particle size compacts, whilst the reduction of PPB decoration in coarse powder particle compacts allows significant grain growth. Tensile test results of as-HIP RR1000 show, good yield strengths, ultimate tensile strengths and ductility, which are comparable with extruded and isothermal forged RR1000 disc material. Dwell crack propagation tests show that finer powder particle size compacts, which have received a sub-solvus heat treatment, give the highest crack growth rates; whilst the remaining material conditions show markedly improved crack growth resistance. In conclusion, as-HIP RR1000 demonstrates clear potential for use in non-critical applications, employing either powder particle size fraction used in this study subject to the appropriate solution heat treatment.

scholarly journals Direct Shear Strength on the São Francisco River Bank, Northeastern Brazil, With or Without Roots of Different Native Species

2020 ◽  
Vol 9 (1) ◽  
pp. 146
Author(s):  
Igor Pinheiro da Rocha ◽  
Francisco Sandro Rodrigues Holanda ◽  
Mario Monteiro Rolim ◽  
Alceu Pedrotti ◽  
Marks Melo Moura ◽  
...  
Keyword(s):  
Internal Friction ◽  
Native Species ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Northeastern Brazil ◽  
Degree Of Saturation ◽  
Void Content ◽  
Direct Shear ◽  
River Bank ◽  
Angle Of Internal Friction

Several plant species have been studied as reinforcement elements against landslides at slopes, either to protect against the splash effect offered by shoots or anchoring the soil by the root system. The objective of this work was to investigate the influence of roots from shrub species over the soil mechanical attributes such as cohesion and angle of internal friction at the São Francisco riverbank, northeastern Brazil. A trench was excavated under the treetop of every shrubby individual, sampling blocks at 0-0.25, 0.25-0.50, 0.50-0.75, and 0.75-1.00 m depths. The moisture contents, particle size, liquidity limits, plasticity and actual specific mass of the samples were determined. The soil physical and mechanical attributes such as initial and final specific weight, initial and final void content, initial and final degree of saturation, shear resistance peaks, cohesion, and internal friction angle were identified through direct, elementary, consolidated, and undrained tests. In the samples with Solanum paniculatum, Mimosa pigra species, the highest values for cohesion were registered for the samples with roots. Sesbania virgata presented the greatest variation in cohesion and internal friction angle among samples with and without roots. The position and root status influenced the results of the direct shear tests.

scholarly journals Cost Optimization of Cantilever Retaining Wall Using Flower Pollination Algorithm

2021 ◽  
pp. 915-930
Author(s):  
Arpit Mevada ◽  
Vishal Patel ◽  
Dr. Vishal Arekar
Keyword(s):  
Internal Friction ◽  
Structural Stability ◽  
Fitness Function ◽  
Retaining Wall ◽  
Cost Optimization ◽  
Friction Angle ◽  
Flower Pollination Algorithm ◽  
Angle Of Internal Friction ◽  
Flower Pollination ◽  
The Cost

The flower pollination algorithm is nature-inspired in which it mimics the pollination process of the flowers. In this study, the cost of the cantilever retaining wall is optimized, which includes the cost of concrete and the cost of reinforcement steel. The eight design variables define the geometry of the RC wall. The external stability and structural stability are considered as constraints. Overturning, sliding, eccentricity, and bearing are considered external constraints. The structural stability constraints are shear and moment failure of toe slab, heel slab, and stem. The fitness function is developed using a static exterior penalty. The study found that the FPA outperforms the non-dominated sorting genetic algorithm (NSGA-Ⅱ) in this design problem without violating any constraints. An analysis of sensitivity is carried out for the angle of internal friction of backfill soil and the angle of backfill slope. Results show that the total cost rapidly increases after 5 m height of backfill but significantly decreases with the internal friction angle of backfill increases. For backfill heights from 6 to 10 m, the change in cost is significant after the value of the inclination angle of 15°.

scholarly journals Changes in the Strength Characteristics of Glinistx Soils under the Influence of Dynamic Forces

2020 ◽  
Vol 9 (5) ◽  
pp. 639-643
Keyword(s):  
Internal Friction ◽  
Experimental Studies ◽  
Sharp Decrease ◽  
Friction Angle ◽  
Strength Characteristics ◽  
Clay Soils ◽  
Angle Of Internal Friction ◽  
Dynamic Forces ◽  
The Impact ◽  
Soil Indicators

In order to study in depth the impact of vibration on the strength characteristics of clay soils, as well as to develop methods that increase the strength characteristics and contribute to the elimination of seismic shrinkage deformations of clay soils, we conducted research in the field. In field experimental studies, the svaw-12 trailed, smooth vibration roller, manufactured in Germany, was used. We paid special attention to the further behavior of the soil after the vibration and made observations and measurements of soil indicators for two months. The experiments in the field with vibration column showed an increase of soil deformation with increasing duration of the fluctuations, i.e. there is a linear relationship between the increases in soil density on the duration of oscillations. In the process of vibration, there is a sharp decrease in the force of adhesion and the angle of internal friction, which is apparently associated with a violation of the structure of the soil and its compaction. And then at the end of the vibration process, over time, there is an increase in the adhesion (1.5-2 times) and the internal friction angle (1.2 times) of the soil, obviously as a result of the soil acquiring new strength and compaction under the influence of its own weight. This circumstance is also associated with the humidity state of the soil.

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