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Online since: February 2018
Authors: Raffaele Landolfo, Luigi Fiorino, Bianca Bucciero, Tatiana Pali, Maria Teresa Terracciano, Vincenzo Macillo
The input was scaled by a scaling factor from 5% to 120%.
In addition, in order to evaluate the dynamic properties (fundamental vibration frequency and damping ratio), dynamic identification tests were carried out before and after each ICBO-AC156 input by applying a white noise signal.
The results of dynamic identification tests were used to define the dynamic properties, namely fundamental frequency and damping ratio, of bare structure and prototypes (Fig. 4).
Behaviour factor (q) evaluation the CFS braced structures according to FEMA P695.
Experimental characterization of quick mechanical connecting systems for cold-formed steel structures.
In addition, in order to evaluate the dynamic properties (fundamental vibration frequency and damping ratio), dynamic identification tests were carried out before and after each ICBO-AC156 input by applying a white noise signal.
The results of dynamic identification tests were used to define the dynamic properties, namely fundamental frequency and damping ratio, of bare structure and prototypes (Fig. 4).
Behaviour factor (q) evaluation the CFS braced structures according to FEMA P695.
Experimental characterization of quick mechanical connecting systems for cold-formed steel structures.
Online since: March 2018
Authors: Hacene Ameddah, Moussa Amadji, Hammoudi Mazouz
Primarily would be the biomechanical “motion-preserving” properties of the device [9].
To determine the material properties necessary for any prosthesis, the requirements expected of that implant must be defined.
Analysis of factors that may influence range of motion after cervical disc arthroplasty.
The Bryan Cervical Disc: wear properties and early clinical results.
Load-Displacement Properties of Lower Cervical Spine Motion Segments, J.
To determine the material properties necessary for any prosthesis, the requirements expected of that implant must be defined.
Analysis of factors that may influence range of motion after cervical disc arthroplasty.
The Bryan Cervical Disc: wear properties and early clinical results.
Load-Displacement Properties of Lower Cervical Spine Motion Segments, J.
Online since: June 2014
Authors: Xiao Zheng, Xiao Cong Ren, Zhi Xian Sun, Ge Chen
The seepage speed of oil through the porous media is the dominant factor affecting the efficiency of oil extraction.
It is an intrinsic property of material [1].
According to the Darcy law, only the absolute permeability, K, is affected by pore structure.
According to equation .2, the actual length of seepage pores, Lt(λ), is another key factor impacting pore fluid flow rate in the Hagen-Poiseuille equation [4].
Fractal analysis of transport properties of porous media.
It is an intrinsic property of material [1].
According to the Darcy law, only the absolute permeability, K, is affected by pore structure.
According to equation .2, the actual length of seepage pores, Lt(λ), is another key factor impacting pore fluid flow rate in the Hagen-Poiseuille equation [4].
Fractal analysis of transport properties of porous media.
Online since: February 2020
Authors: Siladitya Sukumar, Satya Prakash Kar
L length of the workpiece
liquid mass fraction R Radius of the workpiece
h convective heat transfer coefficient Greek Symbols
sensible heat Δt time step size
H total enthalpy ΔV control volume
k thermal conductivity ΔH nodal latent heat
laser peak intensity τ pulse width
latent heat for fusion κ absorption coefficient
ms millisecond α thermal diffusivity
enthalpy source term λ under-relaxation factor
T temperature σ Stefan-Boltzmann constants t time σc temperature slope of surface tension Source term for laser r-momentum source term z-momentum source term Subscripts Superscripts S solid phase n number of iteration L liquid phase 0 previous time step m melting point Introduction Laser assisted manufacturing process has become popular in the manufacturing industry because of its better accuracy, precision, less heat affected
Laser energy, duty cycle, frequency, pulse width and beam radius and mechanical and optical properties of the processed material are the parameters that greatly influence the laser-material interaction during the machining process and subsequent surface finish.
Titanium alloy is the workpiece material and its thermo-physical properties are taken from literature [10].
Yilbas, Study of affecting Parameters in Laser Hole drilling of sheet metals, Journal of Engineering Materials and Technology. 109 (1987) 282-287
T temperature σ Stefan-Boltzmann constants t time σc temperature slope of surface tension Source term for laser r-momentum source term z-momentum source term Subscripts Superscripts S solid phase n number of iteration L liquid phase 0 previous time step m melting point Introduction Laser assisted manufacturing process has become popular in the manufacturing industry because of its better accuracy, precision, less heat affected
Laser energy, duty cycle, frequency, pulse width and beam radius and mechanical and optical properties of the processed material are the parameters that greatly influence the laser-material interaction during the machining process and subsequent surface finish.
Titanium alloy is the workpiece material and its thermo-physical properties are taken from literature [10].
Yilbas, Study of affecting Parameters in Laser Hole drilling of sheet metals, Journal of Engineering Materials and Technology. 109 (1987) 282-287
Online since: April 2013
Authors: Chun Ching Hsiao, An Shen Siao
However, the material of the fabrication properties limits the conversion ratio of the thermoelectric modules [4].
The temperature variation rate is a critical factor in enhancing the electric response of pyroelectric devices while pyroelectric materials and geometry are determined.
The different heat transfers also affected the efficiency of the Olsen cycle.
Although a commercial PZT bulk material possesses excellent pyroelectric properties, a thick pyroelectric material with a high thermal capacity obstructed quick temperature variations.
Therefore, various patterns in pyroelectric sheets were greatly to affect the efficiency of pyroelectric harvesting converters.
The temperature variation rate is a critical factor in enhancing the electric response of pyroelectric devices while pyroelectric materials and geometry are determined.
The different heat transfers also affected the efficiency of the Olsen cycle.
Although a commercial PZT bulk material possesses excellent pyroelectric properties, a thick pyroelectric material with a high thermal capacity obstructed quick temperature variations.
Therefore, various patterns in pyroelectric sheets were greatly to affect the efficiency of pyroelectric harvesting converters.
Online since: September 2013
Authors: Sri Maharani Lestari, Gerry Liston Putra, Sunaryo Sunaryo
All these forces would affect the tensile, bending, and flexural strength of the boat structure and its hull in particular, and since bending is actually consists of tensile and compression therefore only tensile and flexural strength of the material are investigated in this research.
For safety reason the thickness is multiplied by 1.5 as safety factor, and therefore for the chosen boat the proposed thickness of the side hull will be 10 mm, and the bottom hull will be 18 mm.
In the case study application on a 28 m patrol boat the composite thickness efficiency of the VARTM method could reach as high as 45% compare to hand lay-up method, and this will also affect the production cost of the boatyard.
ASTM D3039-00, Standard Test Method For Tensile Properties Of Polymer Matrix Composite Materials.
[12]Wonderly Christopher et al. (2005)Comparison of mechanical properties of glass fiber/vinyl ester and carbon fiber/vinyl ester composites.
For safety reason the thickness is multiplied by 1.5 as safety factor, and therefore for the chosen boat the proposed thickness of the side hull will be 10 mm, and the bottom hull will be 18 mm.
In the case study application on a 28 m patrol boat the composite thickness efficiency of the VARTM method could reach as high as 45% compare to hand lay-up method, and this will also affect the production cost of the boatyard.
ASTM D3039-00, Standard Test Method For Tensile Properties Of Polymer Matrix Composite Materials.
[12]Wonderly Christopher et al. (2005)Comparison of mechanical properties of glass fiber/vinyl ester and carbon fiber/vinyl ester composites.
Online since: January 2022
Authors: Ahmad Khairulikram Zahari, Nurul Wahida Ahmad Khairuddin, Esther Phillip, Muhammad Fathi Sujan
Before geopolymerization takes place, the fly ash feed materials need to be characterized to determine factors contributing to its synthesis behavior and overall end product quality.
Factors that can influence the concentration differs for each country depending on the mineral content of coal feed used, which are sourced from different mines in different countries [10].
Results and Discussion Physical and Chemical Properties of Fly Ash.
Zarina, The Processing Characterization and Properties of Fly Ash Based Geopolymer Concrete, Rev.
Tests for Mechanical and Physical Properties of Aggregates.
Factors that can influence the concentration differs for each country depending on the mineral content of coal feed used, which are sourced from different mines in different countries [10].
Results and Discussion Physical and Chemical Properties of Fly Ash.
Zarina, The Processing Characterization and Properties of Fly Ash Based Geopolymer Concrete, Rev.
Tests for Mechanical and Physical Properties of Aggregates.
Online since: December 2010
Authors: Zhao Yang Zhang, Fei Chen, Yao Min Wang
And the magnification factor of the imaging system was 0.25.
Thus, after laser beam passing through the LCD mask, the amplitude or phase parameters of incident laser beam can be adjusted due to the optical polarization properties and birefringence properties of liquid crystal molecule.
Some of heat-affected zones would be formed around the ablation region.
If the laser energy was excessive, the heat-affected zone was excessive and the graphics morphology would be deteriorated.
Moreover, the shape of laser spot can be changed due to the existence of opaque-lattice effect, so the modulation function of laser beam using LCD mask is affected.
Thus, after laser beam passing through the LCD mask, the amplitude or phase parameters of incident laser beam can be adjusted due to the optical polarization properties and birefringence properties of liquid crystal molecule.
Some of heat-affected zones would be formed around the ablation region.
If the laser energy was excessive, the heat-affected zone was excessive and the graphics morphology would be deteriorated.
Moreover, the shape of laser spot can be changed due to the existence of opaque-lattice effect, so the modulation function of laser beam using LCD mask is affected.
Online since: September 2016
Authors: Zhanna G. Kovalevskaya, Evgeny A. Kovalevskiy, Margarita Khimich
This leads to a change of mechanical and performance characteristics of finished items.
Taking into account this dependence the mechanical separation of powders was carried out.
Changes of the structure and phase composition of the alloy formed at different cooling rates affect the microhardness values.
Sidky, Metallic and ceramic coatings: production, high temperature properties and applications, Longman Scientific & Technical, 1989
Yang, Properties of solid and reticulated mesh components of pure iron fabricated by electron beam melting, J.
Taking into account this dependence the mechanical separation of powders was carried out.
Changes of the structure and phase composition of the alloy formed at different cooling rates affect the microhardness values.
Sidky, Metallic and ceramic coatings: production, high temperature properties and applications, Longman Scientific & Technical, 1989
Yang, Properties of solid and reticulated mesh components of pure iron fabricated by electron beam melting, J.
Online since: April 2010
Authors: Marek Gebura, Juraj Lapin
Introduction
Nickel-based single crystal (SC) superalloys are widely used in aircraft and power engineering
for manufacturing first stage blades for gas turbines due to their unusual ability to retain excellent
combination of mechanical properties and corrosion resistance at high temperatures.
In the interest of designing and validating new nonconventional lifetime assessment models for nickel-based SC superalloy turbine blades, it is important to know and understand microstructure degradation processes which takes place during their service and also related changes in their mechanical properties [8].
Since the coarsening of the γ' precipitates represents a considerable contribution to all degradation processes affecting performance and service life of turbine blades, it is important to study this inhomogeneity in detail with respect to chemical heterogeneity, activation energy for coarsening, time exponent, effective diffusion coefficient and γ/γ' interfacial energy which control coarsening kinetics of the cuboidal γ' precipitates.
In both areas, the coarsening process is diffusion controlled and its behaviour can be described by a standard LSW coarsening equation in the form [10]: ( ) 1/3 3 3 1/3 0 1 , a a k t− = (3) where k1 is the coarsening rate coefficient defined as: 1 32 1 64 9 / effD C Ω k , RT σ∞ = (4) where C∞ is the molar solubility of controlling solute in the matrix, σ is the γ/γ' interfacial energy, Ω is the molar volume of the precipitate and Deff is the effective diffusion coefficient in the γ matrix that should be related to the fluxes of all n components according to relationship in the form [11]: eff eff 0 exp , Q D D RT = − (5) where the pre-exponential factor D0 is defined as: 00 1 , n i i i D x D = =∑ (6) where xi is the mole fraction of i-th element in the γ' precipitate and D0i is the pre-exponential factor of i-th element in the γ matrix.
In the interest of designing and validating new nonconventional lifetime assessment models for nickel-based SC superalloy turbine blades, it is important to know and understand microstructure degradation processes which takes place during their service and also related changes in their mechanical properties [8].
Since the coarsening of the γ' precipitates represents a considerable contribution to all degradation processes affecting performance and service life of turbine blades, it is important to study this inhomogeneity in detail with respect to chemical heterogeneity, activation energy for coarsening, time exponent, effective diffusion coefficient and γ/γ' interfacial energy which control coarsening kinetics of the cuboidal γ' precipitates.
In both areas, the coarsening process is diffusion controlled and its behaviour can be described by a standard LSW coarsening equation in the form [10]: ( ) 1/3 3 3 1/3 0 1 , a a k t− = (3) where k1 is the coarsening rate coefficient defined as: 1 32 1 64 9 / effD C Ω k , RT σ∞ = (4) where C∞ is the molar solubility of controlling solute in the matrix, σ is the γ/γ' interfacial energy, Ω is the molar volume of the precipitate and Deff is the effective diffusion coefficient in the γ matrix that should be related to the fluxes of all n components according to relationship in the form [11]: eff eff 0 exp , Q D D RT = − (5) where the pre-exponential factor D0 is defined as: 00 1 , n i i i D x D = =∑ (6) where xi is the mole fraction of i-th element in the γ' precipitate and D0i is the pre-exponential factor of i-th element in the γ matrix.