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Online since: July 2017
Authors: Ling Hao Kong, Xiao Dong Tan, Dao Ru Li
Introduction
Generator is a kind of mechanical equipment that converts other forms of energy.
In the process of curing and heating of stator coil, the curing curve is divided into three sections, one group of heating curing curve showed as Fig.1: Fig. 1 Solidification curve of stator bar Firstly, we analyzed epoxy resin from physical properties [4].
We found three-stage heating curve meets the requirements of the gelling process of epoxy resin: Through the three-stage curve, adverse effects caused by the heating of the epoxy could be lowered to the minimum, also, make the temperature of the bar cold down to the curing temperature slowly; From the analysis of automatic control theory, the set value for ramp function, the overshoot of the system will be greatly reduced, environmental factors, coupling factors such as disturbance of the system will be reduced too, the heating temperature will be coincide with the given temperature better.
Based on the above analysis, the most important processing parameters of generator stator bar are t1, T2, t1, T2 these four parameters, these four parameters directly affect the final processing results of the wire rod.
Analyzing how these two parameters affect bar’s dielectric loss is same as researching how they affect last processing effect.
In the process of curing and heating of stator coil, the curing curve is divided into three sections, one group of heating curing curve showed as Fig.1: Fig. 1 Solidification curve of stator bar Firstly, we analyzed epoxy resin from physical properties [4].
We found three-stage heating curve meets the requirements of the gelling process of epoxy resin: Through the three-stage curve, adverse effects caused by the heating of the epoxy could be lowered to the minimum, also, make the temperature of the bar cold down to the curing temperature slowly; From the analysis of automatic control theory, the set value for ramp function, the overshoot of the system will be greatly reduced, environmental factors, coupling factors such as disturbance of the system will be reduced too, the heating temperature will be coincide with the given temperature better.
Based on the above analysis, the most important processing parameters of generator stator bar are t1, T2, t1, T2 these four parameters, these four parameters directly affect the final processing results of the wire rod.
Analyzing how these two parameters affect bar’s dielectric loss is same as researching how they affect last processing effect.
Online since: November 2012
Authors: Guo Liang Xie, Xiang Peng Xiao, Qiang Song Wang, Lijun Peng, Bai Qing Xiong
In this study, the effect of microstructure and mechanical properties of Cu-2.1Ni-0.5Si-0.2Zr-0.05Cr leadframe alloy after cold deformation was investigated.
The relationship between mechanical and electrical properties and the microstructural parameters was characterized to optimize the thermomechanical process condition of Cu-Ni-Si-Zr -Cr alloy.
Results and discussions Mechanical properties.
It was because secondary phase precipitating process was more easily to be activated at high temperature than at low temperature during the primary stage of artificial aging and the precipitates at this period was coherent with the base lattice and then led lattice distortion, which is a key factor to get peak hardness of the alloy[14].
The key factors of effects on conductivity of solid solutions are total volume and size of the solute particle, but elements and grain boundary also substantially affect the conductivity [15].
The relationship between mechanical and electrical properties and the microstructural parameters was characterized to optimize the thermomechanical process condition of Cu-Ni-Si-Zr -Cr alloy.
Results and discussions Mechanical properties.
It was because secondary phase precipitating process was more easily to be activated at high temperature than at low temperature during the primary stage of artificial aging and the precipitates at this period was coherent with the base lattice and then led lattice distortion, which is a key factor to get peak hardness of the alloy[14].
The key factors of effects on conductivity of solid solutions are total volume and size of the solute particle, but elements and grain boundary also substantially affect the conductivity [15].
Online since: October 2010
Authors: Mao Fa Jiang, Cheng Jun Liu, Ya He Huang
Alloying Elements such as Mn, Ni, Cr and so on, which can affect the characteristics of phase transformation of steel, are added into steel in order to obtain optimum microstructure and mechanical properties.
As the kind of common micro alloy element, vanadium is used to improve the properties of steel, such as strength, wear resistance and so on [1-3].
Numerous researches reveal that [4-9], vanadium exists in the steel as the form of solid solution and carbonitride; In addition to the solution and precipitation strengthening, vanadium can notably affect the characteristics of phase transformation for steels.
But the diffusion coefficient of vanadium atoms is about 5 orders of magnitude lower than carbon atoms, therefore the diffusion and distribution of vanadium is one of controlling factors of pearlite transformation for heavy rail steel.
Materials for Mechanical Engineering.
As the kind of common micro alloy element, vanadium is used to improve the properties of steel, such as strength, wear resistance and so on [1-3].
Numerous researches reveal that [4-9], vanadium exists in the steel as the form of solid solution and carbonitride; In addition to the solution and precipitation strengthening, vanadium can notably affect the characteristics of phase transformation for steels.
But the diffusion coefficient of vanadium atoms is about 5 orders of magnitude lower than carbon atoms, therefore the diffusion and distribution of vanadium is one of controlling factors of pearlite transformation for heavy rail steel.
Materials for Mechanical Engineering.
Online since: January 2013
Authors: Lin Jie Li, Yan Xin Zhang
Whilst the strongest tendon on the body, the Achilles tendon (AT) is also one of the tendons that are most commonly affected by spontaneous complete rupture [1, 2].
The model comprised of 13 segments, 12 joints and 23 degree-of-freedom (DOF) mechanical linkages, which enables enabled movements in the sagittal, frontal and coronal planes, and was actuated by 54 muscle-tendon units.
Biomechanical properties, such as viscoelasticity and tensile strength, are integral to tendon function and attributable to elastin and collagen fibres and their metabolism.
Due to the viscoelastic properties of the tendon, this high strain rate may result in large amount of stress, which is one of the major injury factors for acute Achilles tendon rupture.
Munro: Dorsiflexion Capacity Affects achilles tendon loading during Drop Landings.
The model comprised of 13 segments, 12 joints and 23 degree-of-freedom (DOF) mechanical linkages, which enables enabled movements in the sagittal, frontal and coronal planes, and was actuated by 54 muscle-tendon units.
Biomechanical properties, such as viscoelasticity and tensile strength, are integral to tendon function and attributable to elastin and collagen fibres and their metabolism.
Due to the viscoelastic properties of the tendon, this high strain rate may result in large amount of stress, which is one of the major injury factors for acute Achilles tendon rupture.
Munro: Dorsiflexion Capacity Affects achilles tendon loading during Drop Landings.
Online since: May 2015
Authors: Wei Guo Liu, Huan Liu, Yan Guo, Lei Wu, Fei Li, Shun Zhou
In general, polymer film smoothing mechanism is a very complicated process which affected by many factors[2].
For different kind of photoresists, the spin coating conditions are not same, need to select the appropriate coating conditions based on the photoresist properties.
These causal factors have an impact on the film roughness.
These factors will exert a good or bad effect on roughness.
[4] Fu Yongqi, Zhao Jingli, Analysis on influence factors of film thickness uniformity of centrifugal coated, J.
For different kind of photoresists, the spin coating conditions are not same, need to select the appropriate coating conditions based on the photoresist properties.
These causal factors have an impact on the film roughness.
These factors will exert a good or bad effect on roughness.
[4] Fu Yongqi, Zhao Jingli, Analysis on influence factors of film thickness uniformity of centrifugal coated, J.
Online since: February 2011
Authors: Chang He Li, Ling Yun Qi, Lin Gang Li, Yu Cheng Ding
Results indicated that the frictional factor and the wear rate of nanometric ZrO2 ceramics decreased significantly under identical working and frictional conditions compared with ZrO2.
However, its high fragility and low strength restricted its application in the weight-bearing parts in the human body, so the selective addition of second-phase particles and whiskers as well as other methods were adopted to improve its mechanical properties.
Xu Shuhua and Huang Chuanyong also made studies on the microstructures and properties of HA-ZrO2 composite materials.
He believed that the phase-transition ZrO2 toughened ceramics had better mechanical properties than other dental ceramics, and its chemical stability also met the requirement when it was used as dental ceramics.
Quinn et al. studied the effects of microstructures and the chemical composition on the mechanical properties of dental ceramics and also believed that ZrO2 ceramics possessed better mechanical properties as dental ceramics.
However, its high fragility and low strength restricted its application in the weight-bearing parts in the human body, so the selective addition of second-phase particles and whiskers as well as other methods were adopted to improve its mechanical properties.
Xu Shuhua and Huang Chuanyong also made studies on the microstructures and properties of HA-ZrO2 composite materials.
He believed that the phase-transition ZrO2 toughened ceramics had better mechanical properties than other dental ceramics, and its chemical stability also met the requirement when it was used as dental ceramics.
Quinn et al. studied the effects of microstructures and the chemical composition on the mechanical properties of dental ceramics and also believed that ZrO2 ceramics possessed better mechanical properties as dental ceramics.
Online since: August 2015
Authors: Mourad Khelifa, Van Diem Thi
Properties such as straightness, dimensional stability, unlimited length and interchangeability with unjointed timber make it suitable for the above cited applications.
Several timber-related factors are also known to affect the strength of finger-joints, such as species, density, and natural defects, while others are related to the gluing process.
In order to better understand the mechanical behaviour of timber beams in bending, a non-linear numerical analysis is necessary.
The material properties for Spruce wood are: E1 = 12.7GPa; E2=E3=0.43GPa; n12=n13=0.39; n23 = 0.51; G12=G13=0.73 GPa; G23 = 0.03 GPa; syield = 55 MPa; Q = 0.75 GPa; b=17; F= 0.35; G = 0.4; H = 0.6; L = 1.5; M = 1.5; N = 1.45.
Cohesive zone models (CZM’s) were used to simulate these fractures, whose properties were estimated from literature data.
Several timber-related factors are also known to affect the strength of finger-joints, such as species, density, and natural defects, while others are related to the gluing process.
In order to better understand the mechanical behaviour of timber beams in bending, a non-linear numerical analysis is necessary.
The material properties for Spruce wood are: E1 = 12.7GPa; E2=E3=0.43GPa; n12=n13=0.39; n23 = 0.51; G12=G13=0.73 GPa; G23 = 0.03 GPa; syield = 55 MPa; Q = 0.75 GPa; b=17; F= 0.35; G = 0.4; H = 0.6; L = 1.5; M = 1.5; N = 1.45.
Cohesive zone models (CZM’s) were used to simulate these fractures, whose properties were estimated from literature data.
Online since: July 2017
Authors: Barbara de Nicolo, Daniel Meloni
Most of existing and historical buildings in Italy are masonry structures, whose functional and architectonical requalification usually consists of new openings in masonry walls, but, according to the above mentioned principle, these modifications need to be designed at least without significantly affecting the pre-existent structural behavior.
But at the macro-scale, usually addressed for buildings design and verification, literature, National and International Codes [1, 4, 6] reduce this complexity to panels failure macro-modes, after homogenization of constituents properties.
With regard to vertical loads, instability and cracking in presence of out-of-plane eccentricities is accounted by means of tabular methods (F Factor Method) [1, 4].
Masonry elements are modeled according to a solid continuum approach, usually performed via FEM, after application of homogenization techniques when constituents properties are experimentally evaluated [5, 8], or, more frequently, using global properties experimentally tested on representative specimens.
Following this approach, several macro-elements formulations have been proposed in the literature [12] as an evolution of simple beam elements, embodying more elastic properties and non-linear behavior for pushover analyses.
But at the macro-scale, usually addressed for buildings design and verification, literature, National and International Codes [1, 4, 6] reduce this complexity to panels failure macro-modes, after homogenization of constituents properties.
With regard to vertical loads, instability and cracking in presence of out-of-plane eccentricities is accounted by means of tabular methods (F Factor Method) [1, 4].
Masonry elements are modeled according to a solid continuum approach, usually performed via FEM, after application of homogenization techniques when constituents properties are experimentally evaluated [5, 8], or, more frequently, using global properties experimentally tested on representative specimens.
Following this approach, several macro-elements formulations have been proposed in the literature [12] as an evolution of simple beam elements, embodying more elastic properties and non-linear behavior for pushover analyses.
Online since: November 2016
Authors: Koji Hagihara, Haruka Araki, Takaaki Ikenishi, Takayoshi Nakano
This determination is made since only the {013} slip which exhibits significant yield-stress anomaly [20,21] can be operative in the C11b-V1 grains and the Schmid factors associated with other slip systems are negligible at the [001] loading axis [17].
Umakoshi, Mechanical properties of C40-based ternary Mo(Si,Al)2 and quaternary (Mo,Zr)(Si,Al)2 silicides, Scripta Mater. 38 (1998) 471-476
Mishima, Microstructure and mechanical properties of MoSi2/TaSi2 two-phase alloys, Intermetallics 14 (2006) 1358-1363
Nakano, Misfit strain affecting the lamellar microstructure in NbSi2/MoSi2 duplex crystals, Acta Mater. 61 (2013) 3432-3444
Yamaguchi, Microstructure and mechanical properties of MoSi2 single crystals and directionally solidified MoSi2-based alloys, Prog.
Umakoshi, Mechanical properties of C40-based ternary Mo(Si,Al)2 and quaternary (Mo,Zr)(Si,Al)2 silicides, Scripta Mater. 38 (1998) 471-476
Mishima, Microstructure and mechanical properties of MoSi2/TaSi2 two-phase alloys, Intermetallics 14 (2006) 1358-1363
Nakano, Misfit strain affecting the lamellar microstructure in NbSi2/MoSi2 duplex crystals, Acta Mater. 61 (2013) 3432-3444
Yamaguchi, Microstructure and mechanical properties of MoSi2 single crystals and directionally solidified MoSi2-based alloys, Prog.
Online since: August 2019
Authors: Svetlana Romanenko, Yanina Andriievska
After reviewing the many reinforcement schemes, their inadequacies include the impossibility of efficiently unloading the compressed zone of the beam concrete, which significantly affects the stiffness and bearing capacity.
As a result of the experiments, the physical and mechanical properties of concrete and reinforcement are discovered and, based on the obtained results, their final class is determined.
Introduction The main task of construction is providing buildings with the property to remain operable throughout the entire life cycle.
The level of bearing capacity, both of individual structures and buildings as a whole, depends on many factors.
To obtain real physical and mechanical characteristics of materials, samples of reinforcement are selected and concrete samples are formed.
As a result of the experiments, the physical and mechanical properties of concrete and reinforcement are discovered and, based on the obtained results, their final class is determined.
Introduction The main task of construction is providing buildings with the property to remain operable throughout the entire life cycle.
The level of bearing capacity, both of individual structures and buildings as a whole, depends on many factors.
To obtain real physical and mechanical characteristics of materials, samples of reinforcement are selected and concrete samples are formed.