scholarly journals A Finite Element Analysis of the Effects of Graphene and Carbon Nanotubes on Thermal Conductivity of Co Phase in WC–Co Carbide

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7656
Author(s):  
Zhengwu Li ◽  
Wenkai Xiao ◽  
Xuefeng Ruan
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Finite Element ◽  
Thermal Conduction ◽  
Engineering Practice ◽  
Shield Tunneling ◽  
Element Analysis ◽  
Design And Optimization ◽  
Element Simulation ◽  
Proper Curvature

In engineering practice, the service life of cemented carbide shield tunneling machines in uneven soft and hard strata will be seriously reduced due to thermal stress. When carbon nanotubes (CNTs) and graphene nano-platelets (GNPs) are added to WC–Co carbide as enhanced phases, the thermal conductivity of carbide is significantly improved. Research should be performed to further understand the mechanism of enhancement in composites and to find ways to assist the design and optimization of the structure. In this paper, a series of finite element models were established using scripts to find the factors that affect the thermal conduction, including positions, orientations, interface thermal conductivity, shapes, sizes, and so on. WC–Co carbide with CNTs (0.06%, 0.12%, and 0.18% vol.), GNPs (0.06%, 0.12%, and 0.18% vol.) and hybrid CNTs–GNPs (1:1) were prepared to verify the reliability of finite element simulation results. The results show that the larger the interface thermal conductivity, the higher the composite phase thermal conductivity. Each 1%vol of CNTs increased the thermal conductivity of the composite phase by 7.2%, and each 1% vol. of GNPs increased the thermal conductivity of the composite phase by 5.2%. The proper curvature (around 140°) of CNTs and GNPs with a proper diameter to thickness ratio is suggested to lead to better thermal conductivity.

scholarly journals Effect of Graphene and Carbon Nanotubes on the Thermal Conductivity of WC-Co Cemented Carbide

2019 ◽  
Author(s):  
Kui Chen ◽  
Wenkai Xiao ◽  
Zhengwu Li ◽  
Jiasheng Wu ◽  
Kairong Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Service Life ◽  
Bending Strength ◽  
Cemented Carbide ◽  
Engineering Practice ◽  
Shield Tunneling ◽  
Hardness Tester ◽  
Engineering Costs ◽  
Shield Machine

In recent years, it has been found in engineering practice that the service life of cemented carbide shield machine tools used in uneven soft and hard strata is substantially reduced. The study found that thermal stress is the main reason for the failure of cemented carbide shield tunneling tools when shield tunneling is carried out in uneven soft and hard soil. To maintain the hardness of cemented carbide, improving the thermal conductivity of the shield machine tool is of great importance for prolonging its service life and reducing engineering costs. In this paper, graphene and carbon nanotubes were mixed with WC-Co powder and sintered by SPS (Spark Plasma Sintering). The morphology was observed by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A Rockwell hardness tester and bending strength tester were used to test hardness, bending strength and thermal conductivity. The results show that adding trace graphene or carbon nanotubes can increase the bending strength of the cemented carbide by approximately 50% while keeping the hardness of the cemented carbide unchanged. The thermal conductivity of the cemented carbide can be increased by 10% with the addition of 0.12% graphene alone.

Static Characteristics of Micro Disc Magneto Electric Generator – Simulation and Experiment

2013 ◽  
Vol 365-366 ◽  
pp. 356-359
Author(s):  
Lin Du ◽  
Geng Chen Shi ◽  
Jing Jing Zhao
Keyword(s):  
Finite Element ◽  
Structural Design ◽  
Experimental Result ◽  
Static Characteristics ◽  
Element Analysis ◽  
Electric Generator ◽  
Design And Optimization ◽  
Element Simulation ◽  
Simulation And Experiment ◽  
3D Software

Maxwell 3D software of finite-element analysis in electromagnetic fields is used to model and simulate the micro disc magneto electric generator. Distribution characteristics of magnetic induction are required and theoretical analysis and calculation is presented. Error between the simulation result and experimental result is about 6% which verify the rationality and accuracy of finite-element simulation. It can be used to guide the structural design and optimization of this type of generator.

Heat Transfer Analysis of Silicone Oil Fan Clutch Based on Finite Element Simulation

2015 ◽  
Vol 713-715 ◽  
pp. 73-76
Author(s):  
Lin Li ◽  
Xiao Nan Liu ◽  
Xiao Lin Feng
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Silicone Oil ◽  
Thermal Characteristics ◽  
Heat Transfer Analysis ◽  
Element Analysis ◽  
Design And Optimization ◽  
Element Simulation ◽  
Viscous Shear ◽  
The Mathematical Model

Silicone oil fan clutch uses viscous shear force of silicone oil to transfer torque. Friction of silicone oil generates a lot of heat. Thermal analysis is an important link in the design and optimization of the clutch performance. The mathematical model of thermal analysis for silicone oil fan clutch is proposed. The analysis is focused on the advantages of thermal boundary layer FEA (nonlinear finite element analysis) method in the clutch thermal property. Comparing the calculated results with the experimental data, the feasibility and accuracy of the FEA method was confirmed. The main factors influencing on the thermal characteristics of silicone oil fan clutch are studied.

scholarly journals Effect of Graphene and Carbon Nanotubes on the Thermal Conductivity of WC–Co Cemented Carbide

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 377 ◽  
Author(s):  
Kui Chen ◽  
Wenkai Xiao ◽  
Zhengwu Li ◽  
Jiasheng Wu ◽  
Kairong Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Service Life ◽  
Bending Strength ◽  
Cemented Carbide ◽  
Engineering Practice ◽  
Shield Tunneling ◽  
Plasma Sintering ◽  
Engineering Costs ◽  
Shield Machine

In recent years, it has been found that the service life of cemented carbide shield machine tools used in uneven soft and hard strata is substantially reduced in engineering practice. The study found that thermal stress is the main reason for the failure of cemented carbide shield tunneling tools when shield tunneling is carried out in uneven soft and hard soil. To maintain the hardness of cemented carbide, improving the thermal conductivity of the shield machine tool is of great importance for prolonging its service life and reducing engineering costs. In this study, graphene and carbon nanotubes were mixed with WC–Co powder and sintered by spark plasma sintering (SPS). The morphology was observed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The Rockwell hardness, bending strength, and thermal conductivity of the samples were tested. The results show that adding a small amount of graphene or carbon nanotubes could increase the bending strength of the cemented carbide by approximately 50%, while keeping the hardness of the cemented carbide constant. The thermal conductivity of the cemented carbide could be increased by 10% with the addition of 0.12 wt % graphene alone.

Finite Element Analysis of Flow Field in Nano-Laminated Coextrusion Die

2012 ◽  
Vol 501 ◽  
pp. 47-52
Author(s):  
Ti Kun Shan ◽  
Chang Jin Li ◽  
Wei Min Yang ◽  
Shu Jiang Li
Keyword(s):  
Finite Element ◽  
Flow Field ◽  
Flow Characteristics ◽  
Laminated Composite ◽  
Fem Analysis ◽  
Simulation Software ◽  
Element Analysis ◽  
Design And Optimization ◽  
Element Simulation ◽  
New Type

FEM analysis of flow field in nano-laminated coextrusion die is introduced. Nano-laminated coextrusion die is a new type of laminated composite generator which is based on the principle of the melt calculus. The distributions of pressure field and velocity vectors are obtained and analyzed. The result using finite element simulation software Polyflow shows an improvement in structure of die as well as better quality for melt flow characteristics. The paper is helpful in design and optimization of coextrusion die and process.

Research on the Random Vibration Cumulative Fatigue Damage Life Based on the Finite Element Analysis

2013 ◽  
Vol 300-301 ◽  
pp. 992-996
Author(s):  
Cheng Cheng Wang ◽  
Chuan Ri Li ◽  
Tian Ma
Keyword(s):  
Finite Element ◽  
Fatigue Damage ◽  
Simulation Analysis ◽  
Response Spectrum ◽  
Engineering Practice ◽  
Element Analysis ◽  
Element Simulation ◽  
Extreme Response ◽  
The Finite Element Analysis ◽  
Cumulative Fatigue Damage

Aiming at most of the aviation products are facing the problem of fatigue fracture in vibration environment, we analysis the structure of a bracket with ANSYS-Workbench, predict the life of the bracket by different ways, and compared with the testing result, then use the Fatigue damage spectrum (FDS) and Extreme Response Spectrum (ERS) to analysis expected results. The research not only ensure the accuracy of simulation analysis and life predict, but also make a dynamic supervision of product life process, promote the application of finite element simulation analysis in engineering practice.

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.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Finite Element Simulation of Stable Fatigue Crack Growth Using Critical CTOD Determined by Preliminary Finite Element Analysis

2014 ◽  
Vol 891-892 ◽  
pp. 1675-1680
Author(s):  
Seok Jae Chu ◽  
Cong Hao Liu
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Finite Element Simulation ◽  
Crack Growth ◽  
Crack Tip ◽  
Stress Intensity Factor Range ◽  
Crack Tip Opening Displacement ◽  
Element Analysis ◽  
Element Simulation

Finite element simulation of stable fatigue crack growth using critical crack tip opening displacement (CTOD) was done. In the preliminary finite element simulation without crack growth, the critical CTOD was determined by monitoring the ratio between the displacement increments at the nodes above the crack tip and behind the crack tip in the neighborhood of the crack tip. The critical CTOD was determined as the vertical displacement at the node on the crack surface just behind the crack tip at the maximum ratio. In the main finite element simulation with crack growth, the crack growth rate with respect to the effective stress intensity factor range considering crack closure yielded more consistent result. The exponents m in the Paris law were determined.

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