scholarly journals Influence of Temperature on Contact Pressures and Resource of Metal-Polymer Plain Bearings with the Filled Polyamide PA6 Bushing

2021 ◽  
Author(s):  
Myron Chernets ◽  
Mykhaylo Pashechko ◽  
Anatolii Kornienko ◽  
Andrei Buketov
Keyword(s):  
Young’S Modulus ◽  
Dry Friction ◽  
Young's Modulus ◽  
Effect Of Temperature ◽  
Influence Of Temperature On ◽  
Practical Effect ◽  
Design Calculations ◽  
Increasing Temperature ◽  
Contact Pressures ◽  
Metal Polymer

It is known that the elastic characteristics of polyamides change with increasing temperature, in particular, the Young's modulus decreases significantly. This fact is practically not taken into account in design calculations of metal-polymer plain (MP) bearings, operating under conditions of the boundary and dry friction. The purpose of the study is the analysis of the effect of temperature on the change of the Young's modulus and, accordingly, the contact strength and triboresource according to the developed method of calculating MP bearings. MP bearings with a bushing made of polyamide PA6 reinforced with glass or carbon dispersed fibers were investi-gated. Quantitative and qualitative regularities of change of the maximum contact pressures and resource of the bearings at temperature increase under conditions of boundary and dry friction are established. The pressures in the bearing bushing made of PA6+30GF will be lower than for the bushing made of PA6+30CF. The resource of the bushing made of PA6+30CF will be significantly greater than for PA6+30GF. For thermoplastic polymers, the increase in temperature will have a useful practical effect due to the decrease in the rigidity of the polymer composites of the bearing bushing.

THE ELASTIC PROPERTIES OF SILICA GELS

1949 ◽  
Vol 27b (10) ◽  
pp. 781-790 ◽  
Author(s):  
L. A. Munro ◽  
J. G. McNab ◽  
W. L. Ott
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Silica Gels ◽  
Effect Of Temperature ◽  
Compression Method ◽  
Silicate Concentration ◽  
Acid Gel ◽  
Increasing Temperature ◽  
Effect Of Age

The effect of age, concentration, and temperature on the Young's modulus of acid and alkaline silica gels bas been measured by a compression method. For the range of concentrations used the Young's modulus is not independent of load. The modulus increases with age of the gel and with concentration. Hurd's criterion of the time of set (tilted rod method) has been evaluated in terms of absolute units. The effect of temperature on the elastic properties is different for acid and alkaline gels. The Young's modulus values for the former (pH 5.6) increase, while for the alkaline gel (pH 8.2) of the same silicate concentration the values decrease with increasing temperature. The modulus for the alkaline gel is higher than for the acid gel at the lower temperatures. A mechanism is suggested to explain these differences.

Effect of temperature on properties of aluminum/single-walled carbon nanotube nanocomposite by molecular dynamics simulation

2019 ◽  
Vol 234 (2) ◽  
pp. 635-642 ◽  
Author(s):  
Mohsen Motamedi ◽  
AH Naghdi ◽  
SK Jalali
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strain Curve ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Metal Composite

Composite materials have become popular because of high mechanical properties and lightweight. Aluminum/carbon nanotube is one of the most important metal composite. In this research, mechanical properties of aluminum/carbon nanotube composite were obtained using molecular dynamics simulation. Then, effect of temperature on stress–strain curve of composite was studied. The results showed by increasing temperature, the Young’s modulus of composite was decreased. More specifically increasing the temperature from 150 K to 620 K, decrease the Young’s modulus to 11.7%. The ultimate stress of composite also decreased by increasing the temperature. A continuum model of composite was presented using finite element method. The results showed the role of carbon nanotube on strengthening of composite.

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

The Influence of Temperature on the Galvanic Corrosion in Multi-Material System in Seawater

2015 ◽  
Vol 1101 ◽  
pp. 225-228
Author(s):  
Chun Li Wang ◽  
Jian Hua Wu
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Effect Of Temperature ◽  
Material System ◽  
Ni Alloy ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Zero Resistance ◽  
Increasing Temperature ◽  
Surface Morphologies

The galvanic corrosion behavior of titanium (TA2)/Cu-Ni alloy (B10)/low alloy steel (921A) multi-material system has been studied using a zero-resistance ammeter (ZRA) in seawater at different temperatures. After the tests, the surface morphologies of the samples were detected by SEM. Results showed galvanic corrosion behavior of TA2/B10/921A fulfill the mixed potential theory, 921A acts as the anode and both TA2 and B10 act as the cathodes. The effect of temperature on the galvanic corrosion is important, the corrosion rate increases with increasing temperature.

Thermal Cycling Effect on Mechanical Properties, Grain Size and Residual Stress in Alumina and Yttria-Stabilized Tetragonal Zirconia

2014 ◽  
Vol 875-877 ◽  
pp. 1642-1646
Author(s):  
Jing Zhang
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Thermal Cycling ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Tetragonal Zirconia ◽  
Thermal Cycles ◽  
Optical Applications ◽  
Increasing Temperature

Alumina and zirconia are important materials for energy and optical applications. In this study, the effect of thermal cycling on grain size and residual stress was reported. Residual stress was measured using X-ray diffraction (XRD) sin2ψ method for the as-received and the samples after thermal cycling up to 900 cycles. For alumina, the measured residual stress is approximately 96 MPa in tensile for the as-received material, and increases to its highest value of 480 MPa after 650 thermal cycles. The residual stress decreases from 480 MPa to 96 MPa in tensile with increased thermal cycling from 650 to 900 cycles. The crystallized grain size calculated from the diffraction pattern shows that the mean crystallized grain size is about 93 nm for the as-received and increases to 232 nm after 650 thermal cycles. This result is consistent with the enlarged grain size observed by scanning electron microscopy for the alumina after 650 thermal cycles reported earlier. With continued thermal cycling up to 900 cycles, the crystallized grain size is greatly reduced to 104 nm. It suggests that evolution of the crystallized grain size is correlated with the residual stress. For yttria-stabilized tetragonal zirconia (Y-TZP), the mechanical properties at room temperature, are consistent with the property values provided by the manufacturer. The Young’s modulus of shows a non-linear inverse relationship with increasing temperature. The degradation of the Young’s modulus mostly occurs prior to 400 °C and to a less extent in the temperature range of 400 °C up to 850 °C. The Vickers hardness number for the as-received Y-TZP material decreases to a very small extent after 560 thermal cycles and increases approximately 2%, after 1200 thermal cycles. This is consistent with the trend of the Young’s modulus for thermal-cycled specimens.

Effect of Temperature on Elasticity of Silicon Nanowires

2011 ◽  
Vol 483 ◽  
pp. 526-531
Author(s):  
Jing Wang
Keyword(s):  
Young’S Modulus ◽  
Silicon Nanowires ◽  
Strain Energy ◽  
Young's Modulus ◽  
Silicon Nanowire ◽  
Negative Temperature ◽  
Lattice Parameter ◽  
Mechanical Analysis ◽  
Effect Of Temperature ◽  
Continuum Approach

A semi-continuum approach is developed for mechanical analysis of a silicon nanowire, which captures the atomistic physics and retains the efficiency of continuum models. By using the Keating model, the strain energy of the nanowire required in the semi-continuum approach is obtained. Young’s modulus of the silicon (001) nanowire along [100] direction is obtained by the developed semi-continuum approach. Young’s modulus decreases dramatically as the size of a silicon nanowire width and thickness scaling down, especially at several nanometers, which is different from its bulk counterpart. The semi-continuum approach is extended to perform a mechanical analysis of the silicon nanowire at finite temperature. Taking into account the variations of the lattice parameter and the bond length with the temperature, the strain energy of the system is computed by using Keating anharmonic model. The dependence of young’s modulus of the nanowire on temperature is predicted, and it exhibits a negative temperature coefficient.

scholarly journals Note on the influence of temperature on the rigidity of metals

1920 ◽  
Vol 97 (687) ◽  
pp. 450-455
Keyword(s):  
Temperature Effect ◽  
Young’S Modulus ◽  
Test Piece ◽  
Young's Modulus ◽  
Narrow Strip ◽  
Influence Of Temperature ◽  
Complex Constant ◽  
Fine Wire ◽  
Influence Of Temperature On ◽  
Series Of Experiments

In these ‘Proceedings,’ I described some experiments on the influence of temperature on the value of Young’s Modulus for various metals. The results showed that the more fusible the metal, the greater was the variation of the modulus with temperature, and suggested that, roughly, the decrement of the modulus for a given rise of temperature was equal to the ratio of the modulus at absolute zero to the melting temperature and a constant ( i. e. d M/ dθ = M 0 /( θ n + θ ')). Since Young’s Modulus is a complex constant, involving both rigidity and volume elasticity, it seemed worth while to examine the temperature effect on rigidity alone, and with this object in view I have recently carried out a further series of experiments on most of the metals previously tested. The apparatus used was a torsion-balance, shown diagrammatically in fig. 1. A vertical rod, A, is suspended by a long fine wire, B, and the test piece, C, in the form of a wire or narrow strip of plate, is clamped to the lower end of A, and also to the fixed support, D. The whole of this part of the balance can be immersed in a bath of fluid at any required temperature.

scholarly journals Young’s Modulus Calculation of Some Metals Using Molecular Dynamics Method Based on the Morse Potential

2019 ◽  
Vol 2 (1) ◽  
pp. 19
Author(s):  
Fitriana Faizatu Zahroh ◽  
Iwan Sugihartono ◽  
Ernik D. Safitri
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Young’S Modulus ◽  
Morse Potential ◽  
Interatomic Potential ◽  
Young's Modulus ◽  
Strain Curve ◽  
Effect Of Temperature ◽  
Nickel Metal ◽  
Nickel Copper

It has been investigated computationally Young's modulus of some metals: nickel, copper, silver, gold, and aluminum. The offset method can graphically determine Young's modulus property by determining the elastic region based on the straight line intersection formed at a 0.2% strain against the stress-strain curve. In this simulation work, Young’s modulus calculation was performed by using the LAMMPS molecular dynamics software. The interatomic potential used to represent the interactions among atoms of materials in this simulation is the Morse potential. The metals under-investigated in this work are nickel, copper, silver, gold, and aluminum, and we got the results are 209.2 GPa, 110.8 GPa, 83.8 GPa, 79.2 GPa, and 70.3 GPa, respectively. The Young's modulus of the materials was also computed as temperature variations from 300K to the melting point to determine the effect of temperature on Young's modulus, and it is tensile strength. From our work we can found that the higher the temperature, the lower Young's modulus value. In addition, it can be seen that nickel metal has good temperature resistance. This is evidenced by the change in the nickel-metal phase near its melting point.

Effect of Temperature and Holding Time on Zirconia Toughened Alumina (ZTA) Prepared by Two-Stage Sintering

2021 ◽  
Vol 1030 ◽  
pp. 11-18
Author(s):  
Teow Hsien Loong ◽  
Ananthan Soosai ◽  
Suresh Muniandy
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Young’S Modulus ◽  
Sintering Temperature ◽  
Young's Modulus ◽  
Holding Time ◽  
Effect Of Temperature ◽  
Two Stage ◽  
Pinning Effect ◽  
Zirconia Toughened Alumina

The microstructure and mechanical properties of Zirconia Toughened Alumina (ZTA) produced via two-stage sintering at various sintering temperature of T1 and T2 in addition to effect of various holding time were investigated. T1 temperature was set between the range of 1400°C to 1500°C with a heating rate of 20°C/min. The samples were then sintered at T2 ranging from 1350°C to 1400°C followed by various holding time between 2 hours to 12 hours. The sintered samples’ microstructural properties, bulk density, hardness (Vickers hardness), elastic modulus (Young’s modulus) and fracture toughness (K1C) were then determined. Compared to standard holding time of two-stage sintering which is 12 hours, results show that ZTA produced via two-stage sintering with shorter holding time of 4 hours with T1 set at 1500°C and T2 of 1450°C are capable of achieving full densification. In addition, the same sample were also able to achieve hardness up to 19 GPa, Young’s modulus of 390 GPa and fracture toughness of 6.1 MPam1/2. The improvement in mechanical properties can be mainly attributed to the absent of surface diffusion at T2 above 1400°C and also presence of Y-TZP which contributed to lower grain growth due to the pinning effect.

The Effect of Temperature on Tensile and Compressive Strengths and Young's Modulus of Oil Shale

1979 ◽  
Vol 19 (05) ◽  
pp. 301-312 ◽  
Author(s):  
P.J. Closmann ◽  
W.B. Bradley
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Young’S Modulus ◽  
Oil Shale ◽  
Room Temperature ◽  
Young's Modulus ◽  
Effect Of Temperature ◽  
Triaxial Tests ◽  
Process Conditions ◽  
Decomposition Pressure

Abstract The analysis of underground oil-shale recovery processes requires knowledge of the mechanical properties of oil shale at various temperatures. The tensile strength, compressive strength, and Young's modulus are of special importance. The variation of these properties with temperature is important when assessing the strength of underground columns and confining walls for process cavities. This paper presents the results of an experimental study to quantify this temperature dependence. We found that both tensile and compressive strengths of oil shale show a marked decrease in strength as temperature increased, for a given richness. For example, for 15.6 gal/ton oil shale, the tensile strength at 400 deg. F is only 28% of its room temperature value. For 19.2 gal/ton shale, the compressive strength at 400 deg. F with 500-psi confining pressure is 43% of its value at room temperature. At a given temperature, both the tensile and compressive strengths decrease as richness increases, although the rate of decrease diminishes at richnesses of about 42 gal/ton and higher. Equations are developed to permit estimates of the various parameters involved. The compressive Young's moduli show a considerable decrease with temperature. At 400 deg. F the modulus is reduced to 51% of its room temperature value. Introduction In-situ processes for recovery of oil from nahcolite-bearing oil shale usually involve some heating or pyrolysis of the shale. Wet processes (steam, hot water) also involve dissolution of nahcolite to generate pore space and to create permeability. If the leaching of nahcolite is conducted at a sufficiently high temperature, some stress will develop in the rock beyond the heated cavity boundary because of CO2 generation and possibly water vapor, as follows. 2NaHCO3 goes to Na2CO3 + H2O + CO2. When the decomposition pressure of nahcolite is high enough, the rock tends to fracture ("popcorn effect"). Rubbling of the formation then can occur. To predict conditions suitable for fracturing and rubbling, we need to know how the rock tensile strength varies with temperature. McLamore measured the oil-shale tensile strength as a function of orientation of stress. So far as we know, no measurements of tensile strength as a function of temperature have been reported for oil shale. We also need to know the variation of nahcolite decomposition pressure with temperature. This pressure variation was measured by Templeton. The variation of Young's modulus, compressive strength, and Poisson's ratio also have been reported for various richnesses. Logan and Heard studied the compressive Young's modulus and thermal expansion as functions of richness. Compressive strength of oil shale has been studied extensively. This parameter was measured as a function of oil-shale richness for various confining pressures in triaxial tests at temperatures up to 300 deg. C (572 deg. F). The effect of temperature on rocks other than oil shale has also been studied. Knowledge of the compressive strength is important when assessing the possibility of failure of underground supporting walls in mines or with process cavities. Since the reacted oil shale probably will support the walls or the roofs of the process cavities very little, the strength of the supporting walls and roof under process conditions will determine the tendency for subsidence or intercavity communication. SPEJ P. 301^

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