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 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.

Studies on Preparation of Ti3SiC2 Particulate Reinforced Cu Matrix Composite by Warm Compaction and Its Tribological Behavior

2007 ◽  
Vol 534-536 ◽  
pp. 929-932 ◽  
Author(s):  
Tungwai Leo Ngai ◽  
Zhi Yu Xiao ◽  
Yuan Biao Wu ◽  
Yuan Yuan Li
Keyword(s):  
Electrical Conductivity ◽  
Powder Metallurgy ◽  
Relative Density ◽  
Matrix Composite ◽  
Copper Matrix ◽  
High Density ◽  
Green Density ◽  
Warm Compaction ◽  
Copper Matrix Composite ◽  
Particulate Reinforced

Conventional powder metallurgy processing can produce copper green compacts with density less than 8.3 g/cm3 (a relative density of 93%). Performances of these conventionally compacted materials are substantially lower than their full density counterparts. Warm compaction, which is a simple and economical forming process to prepare high density powder metallurgy parts or materials, was employed to develop a Ti3SiC2 particulate reinforced copper matrix composite with high density, high electrical conductivity and high strength. In order to clarify the warm compaction behaviors of copper powder and to optimize the warm compaction parameters, effects of lubricant concentration and compaction pressure on the green density of the copper compacts were studied. Copper compact with a green density of 8.57 g/cm3 can be obtained by compacting Cu powder with a pressure of 700 MPa at 145°C. After sintered at 1000°C under cracked ammonia atmosphere for 60 minutes, density of the sintered compact reached 8.83 g/cm3 (a relative density of 98.6%). Based on these fabrication parameters a Ti3SiC2 particulate reinforced copper matrix composite was prepared. Its density, electrical conductivity, ultimate tensile strength, elongation percentage and tribological behaviors were studied.

Ductile Failure Prediction of Spot Welded Lap Joint

2012 ◽  
Vol 165 ◽  
pp. 285-289 ◽  
Author(s):  
A.A. Borhana ◽  
A.T. Mohamad ◽  
A. Abdul-Latif ◽  
Z. Ahmad ◽  
A. Ayob ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Triaxiality ◽  
Ductile Failure ◽  
Material Damage ◽  
Fe Model ◽  
Lap Joint ◽  
Damage Initiation ◽  
Localized Necking ◽  
The Relationship ◽  
Spot Welded

A finite element (FE) model incorporating a progressive material damage with Rice-Tracey damage initiation criterion is developed in this study. The relationship between local ductility reduction and stress triaxiality was established experimentally. The FE model was validated by comparisons of load-displacement response of the spot welded lap joint specimen at displacement rate of 5 mm/min and the observed ductile failure mechanism. Results show that Rice-Tracey damage initiation criterion used is sufficient to reproduce the observed ductile failure response of the specimen. Failure of the spot welded lap joint is initiated at the HAZ/fusion zone interface with localized necking.

scholarly journals The Effect of Relative Porosity on the Survivability of a Powder Metallurgy Part During Ejection

2021 ◽  
Author(s):  
Daniel Ogbuigwe
Keyword(s):  
Finite Element ◽  
Powder Metallurgy ◽  
Compaction Pressure ◽  
Element Analysis ◽  
Optimal Outcomes ◽  
Relative Porosity ◽  
Frictional Forces ◽  
Powder Part ◽  
Ejection Phase ◽  
Powder Metallurgy Part

The desire to produce functional powder metallurgy (PM) components has resulted in higher compression forces during compaction. This in turn increases the ejection stresses and therefore the possibility of failure during ejection. This failure can be caused by sprig back during ejection due to frictional forces that are generated between the powder part and the die walls. In order to predict these factors a stress analysis of the powder part during ejection was done. Due to complexity, finite element analysis was used to model the powder during compaction and ejection. Since the ejection stage is the most critical stage of the PM process, it is essential to understand the factors that determine the survivability of a part during this stage. This work uses experimental data, finite element modeling and reliability analysis to determine the probability of failure of metallic powder components during the ejection phase. The results show that there is an increased possibility of failure during ejection as compaction pressure is increased. This information can be used by designers and process planners to determine the optimal process parameters that need to be adopted for optimal outcomes during powder metallurgy.

Use of Cenosphere for Making Metal-Microspheres Syntactic Foam through Powder Metallurgy Route

2015 ◽  
Vol 830-831 ◽  
pp. 75-79
Author(s):  
D.P. Mondal ◽  
R. Dasgupta ◽  
Ajay Kumar Barnwal ◽  
Shaily Pandey ◽  
Hemant Jain
Keyword(s):  
Powder Metallurgy ◽  
Relative Density ◽  
Uniform Distribution ◽  
Compaction Pressure ◽  
Syntactic Foam ◽  
Syntactic Foams ◽  
Plateau Stress ◽  
Stress Energy ◽  
Strength And Stiffness ◽  
Powder Metallurgy Route

Cenospheres are very cheap, and are reasonably strong and thermally stable upto 1200°C. In view of this attempt has been made to use these cenosphere for making Titanium syntactic foams with varying relative densities. Precautions were taken for selecting cold compaction pressure to minimize cenosphere crushing. The sintered samples were then characterized in terms of microstructures primarily to see the extent of cenosphere crushing, distribution of cenosphere, and extent of sintering. The foams made using optimized pressure and sintering parameters, exhibits uniform distribution of cenosphere without any significant crushing. The plateau stress, energy absorption and modulus of these foams are varying with the cenosphere content or the relative density, and these parameters can be engineered by varying cenosphere content in the foam. These foams exhibit considerably higher strength and stiffness than the conventional foam and show the possibility of using them for biomedical and engineering applications.

The Development of an Incrementally Loaded Finite Element Model of the Whole Skin Locomotion Mechanism: Discovering the Relationship Between Its Shape and Motion

2008 ◽  
Author(s):  
Derek Lahr ◽  
Dennis Hong
Keyword(s):  
Finite Element ◽  
Physical Mechanism ◽  
Element Model ◽  
Fe Model ◽  
Closed Volume ◽  
Robotic Platform ◽  
Biologically Inspired ◽  
The Relationship ◽  
Biologically Inspired Robot ◽  
Incremental Loading

The Whole Skin Locomotion (WSL) robotic platform is a novel biologically inspired robot that uses a fundamentally different locomotion strategy than other robots. Its motion is similar to the cytoplasmic streaming action seen in single celled organisms such as the amoeba. The robot is composed of a closed volume, fluid filled skin which generally takes the shape of an elongated torus. When in motion the outer skin is used as the traction surface. It is actuated by embedded smart material rings which undergo cyclical contractions and relaxations, generating an everting motion in the torroidially shaped skin. To better understand, design, and optimize this mechanism, it is necessary to have a model of the skin, fluid, and actuators and their interactions with the environment. This paper details the first steps in the development of a non-linear finite element (FE) model which will allow us to study these interactions and predict the shape and motion of the robot under various actuation strategies. A simple membrane element model is introduced from literature and is modified such that an incremental loading strategy can be employed. Finally, an underlying physical mechanism is introduced which could possibly describe the relationship between the shape of and pressure within the membrane skin and motion of the whole skin locomotion robot.

Predicting the Peen Forming Effectiveness of Ti-6Al-4V Strips With Different Thicknesses Using Realistic Finite Element Simulations

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Fan Yang ◽  
Yukui Gao
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Residual Stress Distribution ◽  
Strip Thickness ◽  
Thin Strip ◽  
Fe Model ◽  
Rate Dependent ◽  
Peen Forming ◽  
Proposed Model ◽  
The Relationship

This paper is intended to quantify the relationship between the peen forming effectiveness and various involved parameters through a realistic numerical study. For this purpose, a new finite element (FE) model is proposed with full geometry representation, random shots generation, and rate-dependent material law of kinematic strain-hardening. The mesh sensitivity and effects of boundary conditions are carefully examined. The FE model is validated by comparing the results with the experimental measurements. The proposed model is then used to investigate the effects of the peening intensity (represented as the shot velocity) and the strip thickness on the peen-formed deflection and the residual stress distribution for strips made of Ti-6Al-4V. Our results indicate the existence of a maximum convex deflection for different strip thicknesses. In addition, a reversed deflection (i.e., concaved curvature) is observed for severe peening conditions (i.e., thin strip under high peening intensity). Our simulations verify the previous proposition that a concaved curvature can be generated only when the whole cross section is plastically deformed.

scholarly journals The Effect of Relative Porosity on the Survivability of a Powder Metallurgy Part During Ejection

2021 ◽  
Author(s):  
Daniel Ogbuigwe
Keyword(s):  
Finite Element ◽  
Powder Metallurgy ◽  
Compaction Pressure ◽  
Element Analysis ◽  
Optimal Outcomes ◽  
Relative Porosity ◽  
Frictional Forces ◽  
Powder Part ◽  
Ejection Phase ◽  
Powder Metallurgy Part

The desire to produce functional powder metallurgy (PM) components has resulted in higher compression forces during compaction. This in turn increases the ejection stresses and therefore the possibility of failure during ejection. This failure can be caused by sprig back during ejection due to frictional forces that are generated between the powder part and the die walls. In order to predict these factors a stress analysis of the powder part during ejection was done. Due to complexity, finite element analysis was used to model the powder during compaction and ejection. Since the ejection stage is the most critical stage of the PM process, it is essential to understand the factors that determine the survivability of a part during this stage. This work uses experimental data, finite element modeling and reliability analysis to determine the probability of failure of metallic powder components during the ejection phase. The results show that there is an increased possibility of failure during ejection as compaction pressure is increased. This information can be used by designers and process planners to determine the optimal process parameters that need to be adopted for optimal outcomes during powder metallurgy.

Analysis of magnetic force and dynamic characteristic for non-contact permanent magnet linear drive device

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1337-1345
Author(s):  
Chuan Zhao ◽  
Feng Sun ◽  
Junjie Jin ◽  
Mingwei Bo ◽  
Fangchao Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Dynamic Characteristic ◽  
Driving Force ◽  
Magnetic Circuit ◽  
Response Speed ◽  
Computation Method ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.

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