STUDY ON FATIGUE DAMAGE BELOW THE FATIGUE LIMIT AND THE COAXING EFFECTS

ＳＴＵＤＹＯＮＦＡＴＩＧＵＥＤＡＭＡＧＥＢＥＬＯＷＴＨＥＦＡＴＩＧＵＥＬＩＭＩＴＡＮＤＴＨＥＣＯＡＸＩＮＧＥＦＦＥＣＴＳＷＵＺｈｉｘｕｅ;ＬＵＷｅｎｇｅａｎｄＸＵＨａｏ１）（ＦｕｓｈｕｎＰｅｔｒｏｌｅｕｍｉｎｓｔｉｔｕｔｅ,Ｆｕｓｈｕｎ１１３００１,...     

Micro/nano Indentation and Single Grit Diamond Grinding Mechanism on Ultra Pure Fused Silica

The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very smoothed surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the inf...     

Tool State Detection by Harmonic Wavelet and Sample Entropy

It is a fact that acoustic emission(AE) signals contain potentially valuable information for tool wear and breakage monitoring and detection.However,AE stress waves produced in the cutting zone are distorted by the transmission path and the measurement systems,it is difficult to obtain a reliable result by these raw AE data.It is generally known that the process of tool wear belongs to detect weak singularity signals in strong noise.The objective of this paper is to combine Newland Harmonic wavelet and Richman-Moorman(2000) sample entropy for detecting weak singularity signals embedded in strong signals.First,the raw AE signal is decomposed by harmonic wavelet and transformed into the three-dimensional time-frequency mesh map of the harmonic wavelet,at the same time,the contours of the mesh map with log space is induced.Second,the profile map of the three-dimensional time-frequency mesh map is offered,which corresponds to decomposed level on harmonic wavelets.Final,by computing sample entropy in each level,the weak singularity signal can be easily extracted from strong noise.Machining test was carried out on HL-32 NC turning center.This lathe does not have a tailstock.Tungsten carbide finishing tool was used to turn free machining mild steel.The work material was chosen for ease of machining,allowing for generation of surfaces of varying quality without the use of cutting fluids.In turning experiments,the feasibility for tool condition monitoring is demonstrated by 27 kinds of cutting conditions with the sharp tool and the worn tool,54 group data are sampled by AE.The sample entropy of each level of wavelet decomposed for each one of 54 AE datum is computed,wear tool and shaper tool can be distinguished obviously by the sample entropy value at the 12th level,this is a criterion.The proposed research provides a new theoretical basis and a new engineering application on the tool condition monitoring.     

Fluid Pump Using a Bar-shaped Piezoelectric Transducer

There are two kinds of piezoelectric pumps:check valve pumps and valve-less pumps.Whether to use a check valve or not depends upon the application occasion.To achieve large backpressure for higher flow rates,the pump with check valve is desirable.However,adding check valves implies more complex structure and higher probability of valve blocking,etc.In order to solve the problem,effective driving and transport mechanics with compact construction and reliable service are being sought.In this paper,using the second-order longitudinal vibration mode of a bar-shaped piezoelectric vibrator for driving fluid,a piezoelectric pump is successfully made.The proposed piezoelectric pump consists of coaxial cylindrical shells and a bar-shaped piezoelectric vibrator,which has a disk part and a cone part.The lead zirconium titanate ceramic rings fixed in the vibrator are polarized along the thickness direction.When the second-order longitudinal vibration of the vibrator along its axis is excited,the disk part of the vibrator changes periodically the volume of the chamber and the cone part acts as a pin valve,driving the fluid from the inlet port to the outlet port.Finite elements analysis on the proposed pump model is carried out to verify its operation principle and design by the commercial FEM software ANSYS.Components of the piezoelectric pump were manufactured,assembled,and tested for flow rate and backpressure to validate the concepts of the proposed pump and confirm the simulation results of modal and harmonic analyses.The test results show that the performance of the proposed piezoelectric pump is about 910 mL/min in flow rate with a highest pressure level of 1.5 kPa under 400 V peak-to-peak voltage and 51.7 kHz operating frequency.It is confirmed that this bar-shaped piezoelectric transducer can be effectively applied in fluid transferring mechanism of pump through this research.     

MICROSTRUCTURES AND PROPERTIES OF DZ40M Co-BASE SUPERALLOY AFTER LONG-TERM AGEING AT 950℃

研究了新近开发的一种定向凝固钴基高温合金ＤＺ４０Ｍ９５０℃长期时效后的组织与性能。结果表明,合金时效后室温强度提高,塑性降低,９８０℃,８３ＭＰａ持久性能提高,而８１６℃,２１５ＭＰａ持久性能下降,在时效过程中,初生碳化物Ｍ７Ｃ３和ＭＣ缓慢分解,细小的Ｍ２３Ｃ６在基体中大量析出,Ｍ６Ｃ在一些Ｍ７Ｃ３表面生成。分析认为,合金性能变化主要归因于Ｍ２３Ｃ６沉淀析出,初生碳化物Ｍ７Ｃ３和ＭＣ分解,释放出碳     

Reduction Algorithms Based on Discernibility Matrix: The Ordered Attributes Method

1 IntroductionIn Rough Set Theory[1], Pawall has defined two sorts of infOrInion systems withoat and withdecision attributes, denoted as (U C} and (U C U D) respectthely Rere U is the forrse Of obects,Me C and D aJre the condition attribote set tal the decision attriliute set respectively Their reductsare called reduct and rel8Jtive reduct reSPecttwBy Pawha, a reduct must satisfy a indePendent conditbo, tha is, a reduct 0 / R G C, R is'independent if Vr C R, mD(R) / mD(R-- {r}) f…     

EFFECT OF CARBIDE SOLVATION ON FERRITE FORMATION IN AUSTENITIC STEELS

ＥＦＦＥＣＴＯＦＣＡＲＢＩＤＥＳＯＬＶＡＴＩＯＮＯＮＦＥＲＲＩＴＥＦＯＲＭＡＴＩＯＮＩＮＡＵＳＴＥＮＩＴＩＣＳＴＥＥＬＳＤＡＩＱｉｘｕｎａｎｄＹＡＮＧＲｕｚｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ,...     

Cu—Ni合金组元的偏原子体积与平均原子体积的关系

本文建立了固溶体组元的偏摩尔性质与平均摩尔性质的一般关系式手ＣＣ理论中的偏摩尔性质函数;导出了组元的偏摩尔性质与平均摩尔性质的差值方程和差值约束方程,以及Ｇｉｂｂｓ－Ｄｕｈｅｍ一般式;证明由ＣＣ理论中固溶体平均摩尔性质各组合函数求得的偏摩尔性质是相等的,但在一般情况下,偏摩尔性质不等于组元的平均摩尔性质。以Ｃｕ－Ｎｉ合金和组元的平均原子体积以及组元的偏原子体积的计算为例,证明了这些论述。     

Piston-ring and Cylinder-liner Lubrication in Internal Combustion Engines Based on Thermo-hydrodynamic

Currently the extruded effect,roughness to the lubricant shear thinning,temperature changes and other factors or some combination of a single factor mainly considered in the lubrication study of piston ring-cylinder.In the study of the energy equation,the oil viscosity-temperature properties,adsorption layer characteristics are usually not considered.So the theoretical research is different from the actual situation of engineering.The lubrication of piston ring-cylinder liner system in internal combustion(I...