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Online since: June 2020
Authors: Solehuddin Shuib, Nur Faiqa Ismail, M. Saiful Islam, Rohana Ahmad, M. Amar Shahmin
Feasible boundary conditions and material properties were assigned to the developed muscle areas and joints.
The ranges and distributions of these strains and stresses lean on certain features: the nature of external loading, material properties and geometry of the mandible, including the distribution of bone tissue [2].
The mechanical properties of the materials are presented in Table 1.
Moreover, the shear stresses may induce molecular changes associated with apoptosis of the chondrocytes that could affect the bone.
Khan, “Biological factors responsible for failure of osseointegration in oral implants,” Biology and Medicine, vol. 3, no. 2, pp. 164–170, 2011
The ranges and distributions of these strains and stresses lean on certain features: the nature of external loading, material properties and geometry of the mandible, including the distribution of bone tissue [2].
The mechanical properties of the materials are presented in Table 1.
Moreover, the shear stresses may induce molecular changes associated with apoptosis of the chondrocytes that could affect the bone.
Khan, “Biological factors responsible for failure of osseointegration in oral implants,” Biology and Medicine, vol. 3, no. 2, pp. 164–170, 2011
Online since: January 2017
Authors: Guo Hui Feng, Lin Zhang, Xue Yang, Zhi Qiang Kang
Introduction
Monotectic alloys with dispersion structure can show the special physical and chemical properties.
Such as Al-Bi, Al-Pb, Cu-Pb and Ni-Pb that soft phases are dispersed in matrix phases with the higher mechanical strength are good self-lubricating materials, having been widely used in industrial application of bearing materials [1,2].
Although the decrease of cooling rate can improve the homogeneity of sample temperature field, prolong the common action time of the various influence factors that lead to the liquid-liquid phase segregation during the solidification process of the miscibility gap, and then aggravate macrosegregation of the solidification structure.
Conclusions (1) The lower cooling rate (h=500 W/(m2·K)) can improve the uniformity of temperature field and make the action of Marangoni migration on the L2 phase droplets, but it prolongs the action time of various influence factors of liquid-liquid phase separation during the solidification process of immiscibility gap and intensifies the macrosegregation of solidification structure
(3) The faster cooling rate that increases the nucleation density and decreases the rate of collision and coarsening of L2 phase droplets, shorten the action time of various influence factors during liquid-liquid phase transformation process is beneficial to the homogeneous distribution of solidification structure for hypermonotectic alloys.
Such as Al-Bi, Al-Pb, Cu-Pb and Ni-Pb that soft phases are dispersed in matrix phases with the higher mechanical strength are good self-lubricating materials, having been widely used in industrial application of bearing materials [1,2].
Although the decrease of cooling rate can improve the homogeneity of sample temperature field, prolong the common action time of the various influence factors that lead to the liquid-liquid phase segregation during the solidification process of the miscibility gap, and then aggravate macrosegregation of the solidification structure.
Conclusions (1) The lower cooling rate (h=500 W/(m2·K)) can improve the uniformity of temperature field and make the action of Marangoni migration on the L2 phase droplets, but it prolongs the action time of various influence factors of liquid-liquid phase separation during the solidification process of immiscibility gap and intensifies the macrosegregation of solidification structure
(3) The faster cooling rate that increases the nucleation density and decreases the rate of collision and coarsening of L2 phase droplets, shorten the action time of various influence factors during liquid-liquid phase transformation process is beneficial to the homogeneous distribution of solidification structure for hypermonotectic alloys.
Online since: March 2020
Authors: Ayoub Alsayd, Elsadig Abdallah, Abulmaali M. Taher
This investigation concluded that the quality of steel–concrete interface decreasing with height of concrete section and can directly affect corrosion rate.
From this result, it was observed that chloride content has the strongest effect on corrosion rate compared to other factors.
Sand was used to provide good binding and mechanical properties for the concrete.
That is understandable because the composition of sea water depends on location, collection time, sea water stream, temperature, and many other factors.
This passive layer can be destroyed by chloride addition as well as by other factors such as the carbonation process and concrete quality.
From this result, it was observed that chloride content has the strongest effect on corrosion rate compared to other factors.
Sand was used to provide good binding and mechanical properties for the concrete.
That is understandable because the composition of sea water depends on location, collection time, sea water stream, temperature, and many other factors.
This passive layer can be destroyed by chloride addition as well as by other factors such as the carbonation process and concrete quality.
Online since: August 2013
Authors: Lin Zhu, Yan Chen
After using the mechanism of aerodynamics and collecting wind speed in field experience, Hailong Fou[3] modeled 9 load conditions simulating derrick’s structural mechanical behavior through the analysis of the mathematical model.
The dynamic effect formed by wave loads affected on the derrick passed by platform deck, which is indirect load similar to seismic loads, they are all caused by foundation movement.
Looking medium scale jack-up platform as objects of study, K.G.Grenda [5] investigated dynamic response of derrick under the wave loads, the results shown that in the waters at a depth of more than 50m, wave load dynamic amplification factor had a potentially important effect.
Gusella [6] compared the dynamic characteristics of VegaA platform under wave loads and wind load in theoretical and experimental aspects, analyzed power amplification factor of wave load, provide a direction for further study.
In order to obtain mechanical properties of the steel structural derrick with damages, Yuanqing Wang [15] considered the large deformation in geometric nonlinearity by increment tangent stiffness matrix method including geometric stiffness matrix of element and deformation stiffness matrix.
The dynamic effect formed by wave loads affected on the derrick passed by platform deck, which is indirect load similar to seismic loads, they are all caused by foundation movement.
Looking medium scale jack-up platform as objects of study, K.G.Grenda [5] investigated dynamic response of derrick under the wave loads, the results shown that in the waters at a depth of more than 50m, wave load dynamic amplification factor had a potentially important effect.
Gusella [6] compared the dynamic characteristics of VegaA platform under wave loads and wind load in theoretical and experimental aspects, analyzed power amplification factor of wave load, provide a direction for further study.
In order to obtain mechanical properties of the steel structural derrick with damages, Yuanqing Wang [15] considered the large deformation in geometric nonlinearity by increment tangent stiffness matrix method including geometric stiffness matrix of element and deformation stiffness matrix.
Online since: February 2011
Authors: Ya Peng Liu, Yan Tang, Jia Bin Bi
Design of Vehicle’s Controlling System Used a 4WS Control Method based on BP Neural Network
Yapeng Liua, Yan Tangb and Jiabin Bic
School of Mechanical & Electrical Engineering, Guilin University of Electronic Technology, Guangxi, 541004, China
2Full address of second author, including country
3List all distinct addresses in the same way
aliuyapeng1202@126.com, btangy51@sohu.com, cjiabin117@126.com
Keywords: BP Neural Network; Four-Wheel Steering (4WS); Control Method.
The transfer function for hidden and output layer is the bipolar Sigmoid function : (2) Since it has known from the vehicle’s linear model that the vehicle’s dynamic responses are related with 1/υ and 1/υ2, so these two factors are listed as inputs.
The factors β, Φ and γ given by the trained SNN network, and the curve over time compare with the curve tested from the vehicle, both the high and low speed have satisfactory consistent.
There are 200 samples for each test (each test lasted for 4s, the sampling period of 0.02s). 4side slip model presented in Figure 3: Figure. 3 Part of the side slip use for training NNC Figure 4 is the schematic of training for NNC which consisted by NNC and SNN: Figure. 4 Neural controller (NNC) training diagram In the figure, the role of NNC is: while affected by the υ, δf input by the driver and also the various external disturbances, the vehicle system SNN that have non-linear dynamic characteristics, under the adjustment from the δr given by NNC, make the side slip angle is always kept to a minimum or zero.
Lastly stimulated the controlling system, results showed that this method has better controlling property, and it can improve that vehicle’s active safety and manipulating stability.
The transfer function for hidden and output layer is the bipolar Sigmoid function : (2) Since it has known from the vehicle’s linear model that the vehicle’s dynamic responses are related with 1/υ and 1/υ2, so these two factors are listed as inputs.
The factors β, Φ and γ given by the trained SNN network, and the curve over time compare with the curve tested from the vehicle, both the high and low speed have satisfactory consistent.
There are 200 samples for each test (each test lasted for 4s, the sampling period of 0.02s). 4side slip model presented in Figure 3: Figure. 3 Part of the side slip use for training NNC Figure 4 is the schematic of training for NNC which consisted by NNC and SNN: Figure. 4 Neural controller (NNC) training diagram In the figure, the role of NNC is: while affected by the υ, δf input by the driver and also the various external disturbances, the vehicle system SNN that have non-linear dynamic characteristics, under the adjustment from the δr given by NNC, make the side slip angle is always kept to a minimum or zero.
Lastly stimulated the controlling system, results showed that this method has better controlling property, and it can improve that vehicle’s active safety and manipulating stability.
Online since: September 2013
Authors: Yong Qin Xiao, Yi Ping Wan, Bao Xian Liu
Yet, most scholars just qualitatively studied the acoustic emission feature of rock during mechanical damage.
As for how to establish the relation between acoustic emission parameter and mechanical damage mechanism of rock, we still need to do more researches.
Taking into consideration the representativeness of limestone sample’s mechanical property and in order to avoid sample property dispersion when preparing test specimen from the rock core, in the research, several sets of rock specimens are obtained from a large rock block through dense drilling.
Threshold value of detection is a major controllable factor that affects the sensitivity of the detection system.
Experimental study on triaxial compression deformation and acoustic emission property of rock [J].
As for how to establish the relation between acoustic emission parameter and mechanical damage mechanism of rock, we still need to do more researches.
Taking into consideration the representativeness of limestone sample’s mechanical property and in order to avoid sample property dispersion when preparing test specimen from the rock core, in the research, several sets of rock specimens are obtained from a large rock block through dense drilling.
Threshold value of detection is a major controllable factor that affects the sensitivity of the detection system.
Experimental study on triaxial compression deformation and acoustic emission property of rock [J].
Online since: July 2013
Authors: Lorenzo Peroni, Martina Scapin, Federico Carra, Nicola Mariani
However, also the tensile behavior, which affects phenomena such as spalling, scabbing and fragmentation, has to be investigated to achieve an exhaustive characterization.
In this sense, a lot of works can be found in literature, in which the mechanical behavior of ceramics like glass, graphite, concrete and rock-like materials was studied.
The nominal properties are reported in Table 1.
Table 1: Nominal Properties of R4550 Graphite from SGL Carbon datasheet [7].
The strain-gages used have a nominal resistance of 350 Ω with a nominal gage factor of 1.93.
In this sense, a lot of works can be found in literature, in which the mechanical behavior of ceramics like glass, graphite, concrete and rock-like materials was studied.
The nominal properties are reported in Table 1.
Table 1: Nominal Properties of R4550 Graphite from SGL Carbon datasheet [7].
The strain-gages used have a nominal resistance of 350 Ω with a nominal gage factor of 1.93.
Online since: November 2012
Authors: Jiang Xin Yang, Yi Hua Ni, Hai Guo, Jian Wu
Structure of Parametric Designing Simulation Platform
of Automotive Air Conditioning Condenser
Yihua Ni1,a, Hai Guo2,b, Jian Wu2,c, Jiangxin Yang2,d
1Mechanical Dep. of Engineering College Zhejiang A & F University, 311300, China
2Department of Mechanical Engineering, Zhejiang University, Hangzhou, 310027, China
anyh9904@163.com,bharryggo@163.com,cwujian7087@sina.com,dyangjx@zju.edu.cn
Keywords: Condenser, Parameterization, Finite Element, Simulation Platform
Abstract.
Parameters of both refrigerant side and air side don’t change over time. 2) The flow of refrigerant is one-dimensional flow along the tube length direction. 3) The gravity does not affect the convective heat transfer and pressure drop.
The energy conservation equation: (1) The momentum conservation equation : (2) The air side convection heat transfer coefficient could be got from: (3) And the j factor proposed by Junqi Dong [4] in 2007 under air flow velocity : (4) The refrigerant side convection heat transfer coefficient for single-phase flow (including superheat and subcooled regions) was: (5) for two-phase flow: (6) The pressure drop relations for the refrigerant side in the condenser are different for different regions (single and two-phase regions) [5] For single-phase region: (7) for two-phase region: (8) Parametric designing simulation platform of automotive air conditioning condenser Fluent the software was used to do simulation analysis of thermal characteristics and flow property of condenser.
So the refrigerant side pressure drop correction factor η was introduced to amend the mathematical model.
Through the comparison between experimental and simulation results, the refrigerant side pressure drop correction factor η was introduced to amend the mathematic model and make simulation results closer to the fact.
Parameters of both refrigerant side and air side don’t change over time. 2) The flow of refrigerant is one-dimensional flow along the tube length direction. 3) The gravity does not affect the convective heat transfer and pressure drop.
The energy conservation equation: (1) The momentum conservation equation : (2) The air side convection heat transfer coefficient could be got from: (3) And the j factor proposed by Junqi Dong [4] in 2007 under air flow velocity : (4) The refrigerant side convection heat transfer coefficient for single-phase flow (including superheat and subcooled regions) was: (5) for two-phase flow: (6) The pressure drop relations for the refrigerant side in the condenser are different for different regions (single and two-phase regions) [5] For single-phase region: (7) for two-phase region: (8) Parametric designing simulation platform of automotive air conditioning condenser Fluent the software was used to do simulation analysis of thermal characteristics and flow property of condenser.
So the refrigerant side pressure drop correction factor η was introduced to amend the mathematical model.
Through the comparison between experimental and simulation results, the refrigerant side pressure drop correction factor η was introduced to amend the mathematic model and make simulation results closer to the fact.
Online since: March 2015
Authors: Panichakorn Jesda
The effect of solid particle to TEHLunder sudden load change has affects to the film temperature and film thickness of lubricant in contact region presented by Mongkolwongrojn[4].
The apparent viscosity in power-law viscosity model needs to include the correction factor for viscosity-pressure-temperature by Roelands[12] and the correction factor for nanoparticles and microparticle in the lubricant.
The convergence criteria of film pressure, film temperature and hydrodynamic load are adopted as follows: , and Results and Discussion The roller data, properties of liquid lubricant (SAE-90) and the properties of microparticle (MoS2) and nanoparticle (Al2O3) used in the analysis are given in Table 1, Table 2 and Table 3.
The geometry and coordinate of rollers are defined as shown in Fig.1 Table 1 Physical properties of lubricant (SAE-90) and roller material Equivalent radius, m 0.05 Equivalent modulus of elastic of roller, GPa 220 Inlet temperature of lubricant, K 303.15 Ambient density of the lubricant, kg/m3 892.80 Ambient viscosity of the lubricant, Pa-s 0.114 Specific heat of the lubricant, J/kg-K 1870 Thermal conductivity of the lubricant, W/m-K 0.126 Viscosity-Pressure index (Z1) 0.4706 Table 2 Physical properties of MoS2 Table 3 Physical properties of Al2O3 Brinell hardness, GPa 3.139 Density, kg/m3 3890 Modulus of elasticity, GPa 34 Specific heat, J/kg-K 729 Poisson ratio 0.13 Thermal conductivity, W/m-K 36 Density, kg/m3 4800 Friction coefficient 0.10 Particle diameter, mm 2.0 Fig.1 Geometry and coordinate of rollers Fig. 2(a), Fig.2(b) and Fig.2(c) shown the variation of film pressure, film thickness and film temperature in the contact region for liquid
Rattapasakorn: Effect of nanoparticle additives on rough surface cylinder in line contact under TEHL with non-Newtonian lubricant, Journal of Advanced Mechanical Design, Systems and Manufacturing, Vol.8, No.3 (2014), pp. 1-14
The apparent viscosity in power-law viscosity model needs to include the correction factor for viscosity-pressure-temperature by Roelands[12] and the correction factor for nanoparticles and microparticle in the lubricant.
The convergence criteria of film pressure, film temperature and hydrodynamic load are adopted as follows: , and Results and Discussion The roller data, properties of liquid lubricant (SAE-90) and the properties of microparticle (MoS2) and nanoparticle (Al2O3) used in the analysis are given in Table 1, Table 2 and Table 3.
The geometry and coordinate of rollers are defined as shown in Fig.1 Table 1 Physical properties of lubricant (SAE-90) and roller material Equivalent radius, m 0.05 Equivalent modulus of elastic of roller, GPa 220 Inlet temperature of lubricant, K 303.15 Ambient density of the lubricant, kg/m3 892.80 Ambient viscosity of the lubricant, Pa-s 0.114 Specific heat of the lubricant, J/kg-K 1870 Thermal conductivity of the lubricant, W/m-K 0.126 Viscosity-Pressure index (Z1) 0.4706 Table 2 Physical properties of MoS2 Table 3 Physical properties of Al2O3 Brinell hardness, GPa 3.139 Density, kg/m3 3890 Modulus of elasticity, GPa 34 Specific heat, J/kg-K 729 Poisson ratio 0.13 Thermal conductivity, W/m-K 36 Density, kg/m3 4800 Friction coefficient 0.10 Particle diameter, mm 2.0 Fig.1 Geometry and coordinate of rollers Fig. 2(a), Fig.2(b) and Fig.2(c) shown the variation of film pressure, film thickness and film temperature in the contact region for liquid
Rattapasakorn: Effect of nanoparticle additives on rough surface cylinder in line contact under TEHL with non-Newtonian lubricant, Journal of Advanced Mechanical Design, Systems and Manufacturing, Vol.8, No.3 (2014), pp. 1-14
Online since: September 2013
Authors: Pei Feng Feng, Da Zhen Wang
Effect of Orientation of Reinforcements on the Quality of the Machined Surface in Machining Aluminium Composites
Dazhen Wang1, a, Peifeng Feng1,b
1 College of Mechanical Engineering, Jimei University, Xiamen 361021, China
aemail:dazhenwang@163.com.cn, bemail:pffeng@163.com.cn
Keywords: aluminium composites; precision machining; SiC whisker; orientation; deformation mechanism.
The results show that the orientation of reinforcements in the machined surface will directly affect the deformation mechanism of SiC whiskers, microstructures of the machined surface, and to determine the quality of the machined surface.
Table 1 Physical and mechanical properties of the specimens Experimental materials Volume fraction of Reinforcements j/% Density r/g.cm-3 Tensile Strength sb/MPa Young’s Modulus E/GPa Elongation percentage SiCw/LD2 15 2.85 650 160.0 2.0 SiCw/LD2 25 2.88 660 165.0 1.7 LD2 - 2.70 330 70 16.0 Table 2 Tool materials, configuration type and geometric angle Tool materials Configuration type Geometric angles [°] Slicked edge Cutting solution g0 a0 Kr Kr’ ls polycrystalloid diamond compound inserts (PCD) Welding 0 5 45 45 0 Line 0.3mm Dry cutting The Atom Force Microscope (AFM) is from American Digital Instruments Company, and the tapping mode and Si3N4 probe with a cone angle of 35° are used for examination.
Although the microstructure of the machined surface is controlled by many factors, such as the orientation and the volume fraction and types of SiC whisker reinforcements, and cutting conditions, and cutting tools, the orientation of SiC whisker reinforcements and the different types of the microstructure of the machined surface have a high degree of correlation when other factors remain stabilization.
The results show that the orientation of reinforcements in the machined surface will directly affect the deformation mechanism of SiC whiskers, microstructures of the machined surface, and to determine the quality of the machined surface.
Table 1 Physical and mechanical properties of the specimens Experimental materials Volume fraction of Reinforcements j/% Density r/g.cm-3 Tensile Strength sb/MPa Young’s Modulus E/GPa Elongation percentage SiCw/LD2 15 2.85 650 160.0 2.0 SiCw/LD2 25 2.88 660 165.0 1.7 LD2 - 2.70 330 70 16.0 Table 2 Tool materials, configuration type and geometric angle Tool materials Configuration type Geometric angles [°] Slicked edge Cutting solution g0 a0 Kr Kr’ ls polycrystalloid diamond compound inserts (PCD) Welding 0 5 45 45 0 Line 0.3mm Dry cutting The Atom Force Microscope (AFM) is from American Digital Instruments Company, and the tapping mode and Si3N4 probe with a cone angle of 35° are used for examination.
Although the microstructure of the machined surface is controlled by many factors, such as the orientation and the volume fraction and types of SiC whisker reinforcements, and cutting conditions, and cutting tools, the orientation of SiC whisker reinforcements and the different types of the microstructure of the machined surface have a high degree of correlation when other factors remain stabilization.