scholarly journals FEM modeling on the compaction of Fe and Al composite powders

2015 ◽  
Vol 51 (2) ◽  
pp. 163-171 ◽  
Author(s):  
P. Han ◽  
X.Z. An ◽  
Y.X. Zhang ◽  
Z.S. Zou
Keyword(s):  
Relative Density ◽  
Flow Behavior ◽  
Compaction Pressure ◽  
Pressure Effects ◽  
Von Mises Stress ◽  
Composite Powders ◽  
Al Content ◽  
Ejection Force ◽  
Al Composite ◽  
The Relationship

The compaction process of Fe and Al composite powders subjected to single action die compaction was numerically modeled by FEM method. The relationship between the overall relative density and compaction pressure of the compacts with various Al contents was firstly identified, and the influences of Al content on the local relative density, stress, and their distributions were studied. Then the compaction pressure effects on the above properties with fixed Al content were discussed. Furthermore, detailed flow behaviors of the composite powders during compaction and the relationship between the compaction pressure and the ejection force/spring back of the compact were analyzed. The results show that: (1) With each compaction pressure, higher relative density can be realized with the increase of Al content and the relative density distribution tends to be uniform; (2) When the Al content is fixed, higher compaction pressure can lead to composite compact with higher relative density, and the equivalent Von Mises stress in the central part of the compact increases gradually; (3) Convective flow occurs at the top and bottom parts of the compact close to the die wall, each indicates a different flow behavior; (4) The larger the compaction pressure for each case, the higher the residual elasticity, and the larger the ejection force needed.

scholarly journals Experimental Investigation on Flowability and Compaction Behavior of Spray Granulated Submicron Alumina Granules

ISRN Ceramics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Abhisek Choudhary ◽  
Pandu Ramavath ◽  
Papiya Biswas ◽  
Nukala Ravi ◽  
Roy Johnson
Keyword(s):  
Relative Density ◽  
Surface Area ◽  
Flow Behavior ◽  
Compaction Pressure ◽  
High Surface ◽  
High Surface Area ◽  
Solid Loading ◽  
Alumina Powder ◽  
Flow Measurements ◽  
Spray Dried

Aqueous slurry with various solid loadings (up to 40 wt%) of alumina powder (D50 = 300 nm) with suitable rheological properties were spray dried into granules. Solid loading and feed rate of the slurry are found to have a prominent effect on the shape and size distribution of granules. Powder flow measurements exhibited a cohesive index of 28.45 signifying an extremely cohesive flow due to high surface area and irregular morphology. Finer sizes though it offers high geometrical surface area it leads to more surface contacts and hence, high interparticle friction. Spherical morphology achieved through optimum spray drying parameters significantly reduced the cohesive index to 6.45 indicating free flow behavior. Compaction studies of the spray-dried granules and corresponding plot of relative density versus compaction pressure revealed an agglomerate strength of 500 MPa followed by a plateau-like behavior reaching a maximum in the relative density of 59%-60% of the theoretical values.

scholarly journals Numerical Simulation of Densification of Cu–Al Mixed Metal Powder during Axial Compaction

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 537 ◽  
Author(s):  
Wenchao Wang ◽  
Hui Qi ◽  
Pingan Liu ◽  
Yuanbo Zhao ◽  
Hao Chang
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Relative Density ◽  
Metal Powder ◽  
Dwell Time ◽  
Compaction Pressure ◽  
Diameter Ratio ◽  
Al Content ◽  
Die Compaction ◽  
Initial Packing

The densification mechanism of Cu–Al mixed metal powder during a double-action die compaction was investigated by numerical simulation. The finite element method and experiment were performed to compare the effect of the forming method, such as single-action die compaction and double-action die compaction, on the properties of compact. The results showed that the latter could significantly raise the densification rate and were in good agreement with Van Der Zwan–Siskens compaction equation. The effects of the different initial packing structures on the properties of the compact were studied. The results showed that a high-performance compact could be obtained using a dense initial packing structure at a given compaction pressure. Additionally, the effects of the Al content and compaction pressure on the relative density and stress distribution were analyzed. It was observed that, with an increase in the Al content at a given compaction pressure, the relative density of the compact increased, whereas the stress decreased. Furthermore, when the Al content was fixed, the relative density and stress increased with increasing compaction pressure. The relationship between the relative density and the compaction pressure under different friction conditions was characterized and fitted according to the Van Der Zwan–Siskens compaction equation. The influence mechanisms of die wall friction on the compaction behavior were investigated. It was revealed that friction is a key factor that causes the inhomogeneity of the powder flow and stress distribution. Finally, the effects of the dwell time and height–diameter ratio on the densification behavior were analyzed, and it was found that an increase in the dwell time promoted the densification process, whereas an increase of the height–diameter ratio could hinder the process.

scholarly journals Compaction density variation in powder metallurgy components

2021 ◽  
Author(s):  
Elham Jafar-Salehi
Keyword(s):  
Finite Element ◽  
Powder Metallurgy ◽  
Density Distribution ◽  
Relative Density ◽  
Compaction Pressure ◽  
Density Variation ◽  
Fe Model ◽  
Green Density ◽  
Artificial Neural Network Ann ◽  
The Relationship

The main objective of this research was to study the relationship between green density and compaction pressure in powdered metallurgy. Powder metallurgy has gained popularity and importance because of its near net shape, cost effectiveness and its ability to reduce the complexity of multileveled engineering components. However, powder metallurgy poses challenges that are yet to be fully understood. There are many works performed to address challenges such as the effect of friction, the tool kinematics, handling component prior to sintering and fracture under compaction. This work concentrates on the relationship between green density distribution and compaction pressure. In order to measure the relative density of compacted components, Electron Scanning Microscope was utilized. One can intuitively conceive that the relative density requires more than intuition. It was determined that highest relative density occurs at the center of the specimen and reduces toward the die-powder or punch-powder boundary. For completeness, the application of artificial neural network (ANN) and finite element (FE) model in estimation of green relative density was studied. The results of this research signify that ANN is an excellent technique to determine the relative density distribution of un-sintered compacted specimen. Moreover, finite element method can accurately estimate the average relative density of compacted specimen.

scholarly journals Compaction density variation in powder metallurgy components

2021 ◽  
Author(s):  
Elham Jafar-Salehi
Keyword(s):  
Finite Element ◽  
Powder Metallurgy ◽  
Density Distribution ◽  
Relative Density ◽  
Compaction Pressure ◽  
Density Variation ◽  
Fe Model ◽  
Green Density ◽  
Artificial Neural Network Ann ◽  
The Relationship

The main objective of this research was to study the relationship between green density and compaction pressure in powdered metallurgy. Powder metallurgy has gained popularity and importance because of its near net shape, cost effectiveness and its ability to reduce the complexity of multileveled engineering components. However, powder metallurgy poses challenges that are yet to be fully understood. There are many works performed to address challenges such as the effect of friction, the tool kinematics, handling component prior to sintering and fracture under compaction. This work concentrates on the relationship between green density distribution and compaction pressure. In order to measure the relative density of compacted components, Electron Scanning Microscope was utilized. One can intuitively conceive that the relative density requires more than intuition. It was determined that highest relative density occurs at the center of the specimen and reduces toward the die-powder or punch-powder boundary. For completeness, the application of artificial neural network (ANN) and finite element (FE) model in estimation of green relative density was studied. The results of this research signify that ANN is an excellent technique to determine the relative density distribution of un-sintered compacted specimen. Moreover, finite element method can accurately estimate the average relative density of compacted specimen.

scholarly journals Particulate Scale Numerical Investigation on the Compaction of TiC-316L Composite Powders

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Defeng Wang ◽  
Xizhong An ◽  
Peng Han ◽  
Haitao Fu ◽  
Xiaohong Yang ◽  
...  
Keyword(s):  
Relative Density ◽  
Numerical Investigation ◽  
Compaction Pressure ◽  
Green Compact ◽  
Densification Process ◽  
Compaction Process ◽  
Composite Powders ◽  
Packing Structure ◽  
Die Compaction ◽  
Initial Packing

This paper presents a numerical investigation on the 2D uniaxial die compaction of TiC-316L stainless steel (abbreviated by 316L) composite powders by the multiparticle finite element method (MPFEM). The effects of TiC-316L particle size ratios, TiC contents, and initial packing structures on the compaction process are systematically characterized and analyzed from macroscale and particulate scale. Numerical results show that different initial packing structures have significant impacts on the densification process of TiC-316L composite powders; a denser initial packing structure with the same composition can improve the compaction densification of TiC-316L composite powders. Smaller size ratio of 316L and TiC particles (R316L/RTiC = 1) will help achieve the green compact with higher relative density as the TiC content and compaction pressure are fixed. Meanwhile, increasing TiC content reduces the relative density of the green compact. In the dynamic compaction process, the void filling is mainly completed by particle rearrangement and plastic deformation of 316L particles. Furthermore, the contacted TiC particles will form the force chains impeding the densification process and cause the serious stress concentration within them. Increasing TiC content and R316L/RTiC can create larger stresses in the compact. The results provide valuable information for the formation of high-quality TiC-316L compacts in PM process.

Mechanical Response of Porous Copper Manufactured by Lost Carbonate Sintering Process

2007 ◽  
Vol 539-543 ◽  
pp. 1863-1867 ◽  
Author(s):  
X.F. Tao ◽  
Li Ping Zhang ◽  
Y.Y. Zhao
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Relative Density ◽  
Mechanical Response ◽  
Compaction Pressure ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Three Point Bending ◽  
Porous Copper ◽  
The Impact

This paper investigated the mechanical response of porous copper manufactured by LCS under three-point bending and Charpy impact conditions. The effects of the compaction pressure and K2CO3 particle size used in producing the porous copper samples and the relative density of the samples were studied. The apparent modulus, flexural strength and energy absorption capacity in three-point bending tests increased exponentially with increasing relative density. The impact strength was not markedly sensitive to relative density and had values within 7 – 9 kJ/m2 for the relative densities in the range 0.17 – 0.31. The amount of energy absorbed by a porous copper sample in the impact test was much higher than that absorbed in the three-point bending test, impling that loading strain rate had a significant effect on the deformation mechanisms. Increasing compaction pressure and increasing K2CO3 particle size resulted in significant increases in the flexural strength and the bending energy absorption capacity, both owing to the reduced sintering defects.

Porous Al2O3/Al catalyst supports fabricated by an Al(OH)3/Al mixture and the effect of agglomerates

2005 ◽  
Vol 20 (3) ◽  
pp. 672-679 ◽  
Author(s):  
Zhen-Yan Deng ◽  
Yoshihisa Tanaka ◽  
Yoshio Sakka ◽  
Yutaka Kagawa
Keyword(s):  
Surface Area ◽  
Compaction Pressure ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Supports ◽  
Al Content ◽  
Starting Mixture ◽  
Mechanical And Electrical Properties ◽  
Uniform Microstructure ◽  
Compact Density

Porous Al2O3/Al catalyst supports were fabricated using a mixture of Al(OH)3 and Al powders, followed by pressureless sintering at a temperature of 600 °C in vacuum. Different pressures were used to prepare green compacts. High compaction pressure led to a high surface area and good mechanical and electrical properties for the sintered specimens. However, when the Al content in the sintered specimen exceeded a definite value, high compaction pressure decreased the surface area abruptly. Scanning electron microscopy observations revealed that agglomeration in the starting mixture has a significant effect on the microstructure of the sintered specimens. High compaction pressure greatly eliminated the agglomerates and led to a uniform microstructure for the sintered specimens. However, when the Al content in the starting mixture was too high, Al particles in the compacts prepared by the high pressure were largely sintered due to the high compact density so that most of the pores were closed. The present study indicates that a suitable compaction pressure is critical to obtaining superior Al2O3/Al supports.

EFFECT OF SPACING AND CLUMPING OF CORN PLANTS ON DENSITY OF CORN-ROOTWORM LARVAE (COLEOPTERA: CHRYSOMELIDAE) PER ROOT SYSTEM

1985 ◽  
Vol 117 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Olga Piedrahita ◽  
C. R. Ellis ◽  
O. B. Allen
Keyword(s):  
Relative Density ◽  
Root System ◽  
Corn Rootworm ◽  
Plant Spacing ◽  
Corn Rootworms ◽  
Corn Plants ◽  
The Relationship ◽  
Field Plots

AbstractThe relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

scholarly journals Propagation Characteristics of Debris Flows Considering Entrainment Effect

2018 ◽  
Vol 7 (3.34) ◽  
pp. 122
Author(s):  
Seokil Jeong ◽  
Junseon Lee ◽  
Chang Geun Song ◽  
Seung Oh Lee
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Flow Behavior ◽  
Prediction Method ◽  
Heavy Rain ◽  
Accurate Analysis ◽  
Propagation Length ◽  
2D Simulation ◽  
Entrainment Effect ◽  
The Relationship

Background/Objectives: Due to the extreme climate and the localized heavy rain, the frequency of debris flow has been increasing. Therefore, there is a growing expectation for accurate numerical analysis.Methods/Statistical analysis: We present a prediction method that can calculate the propagation length of the debris flow. This analysis indicates the relationship between the potential energy and the propagation length of the debris flow. To study the behavior of the debris flow accurately, the change in the momentum force must be considered; otherwise the calculation accuracy of the debris flow behavior is inevitably low.Findings: Entrainment is a common behavior in a debris flow that leads to changes in the momentum force. Here, we analyzed the change in the momentum force using a 2D simulation model that included entrainment. The results show how the debris flow behaves with changes in the momentum force. When entrainment is considered, the propagation length tends to be underestimated. With detailed information, the uncertainty in the prediction accuracy can be reduced.Improvements/Applications: If studies on the material properties of debris flow would be added, it will be possible to carry out various and accurate analysis of the debris flow  

Specific Gravity of Blood and Plasma at 4 and 37 °C

1974 ◽  
Vol 20 (5) ◽  
pp. 615-616 ◽  
Author(s):  
Raymond J Trudnowski ◽  
Rodolfo C Rico
Keyword(s):  
Confidence Interval ◽  
Specific Gravity ◽  
Healthy Volunteers ◽  
Relative Density ◽  
Whole Blood ◽  
Human Whole Blood ◽  
The Relationship ◽  
Density Of Water

Abstract The specific gravity (relative density) of human whole blood and plasma from 25 healthy volunteers was determined gravimetrically. For whole blood it was found to be 1.0621 (95% confidence interval: 1.0652-1.0590) at 4 °C and 1.0506 (95% confidence interval: 1.0537-1.0475) at 37 °C. Plasma specific gravity was 1.0310 (95% confidence interval: 1.0324-1.0296) at 4 °C and 1.0205 (95% confidence interval: 1.0216-1.0193) at 37 °C. All of these values are referred to the density of water at 4 °C. We show the relationship between these values and those given in the literature for measurements at 25 °C. There was a small increase in whole blood specific gravity with increasing hematocrit, but it was not statistically significant over the 40-56 hematocrit range studied.

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