Studying the Impact of the Roughness of the Tool Surface Formed by Ultrasonic Exposure on the Roughness of the Holes being Machined

2019 ◽  
Vol 973 ◽  
pp. 166-169
Author(s):  
Sergey I. Agapov ◽  
Yuriy I. Sidyakin ◽  
Oleg F. Korpelyanskiy
Keyword(s):  
High Speed ◽  
Roughness Parameters ◽  
Tool Surface ◽  
Ultrasonic Techniques ◽  
The Impact

This article investigates the impact that the rake and rear faces of the drill made from high-speed steels of grade P6M5 and grinded by ultrasonic techniques imposes on the roughness of the holes being machined. The experiment showed that microgeometry of the tool sharpened by transmitting ultrasonic impulses into the zone of regrinding featured lower roughness; moreover, roughness parameters of the drilled holes were also improved.

The Dependence of 3D Surface Roughness Parameters on High-Speed Milling Technological Parameters and Machining Strategy

2014 ◽  
Author(s):  
Toms Torims ◽  
Andris Logins ◽  
Pedro Castellano Rosado ◽  
Santiago Gutiérrez ◽  
Rafael Torres
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Production Costs ◽  
Manufacturing Strategy ◽  
Roughness Parameters ◽  
High Speed Milling ◽  
Surface Roughness Parameters ◽  
3D Surface ◽  
3D Surface Roughness ◽  
The Impact

High-speed milling is an effective machining method extensively used in modern material processing. This machining method offers increased efficiency, quality and accuracy of the machined surface as well as considerably reducing overall production costs and machining time. This paper outlines comprehensive research into the impact of the technological strategy and processed materials on carefully selected 3D surface roughness parameters. This research provides manufacturers who use high-speed milling with recommendations on how to better obtain the desired surface roughness parameters. More specifically, it covers multifactorial analysis of the following factors: feed rate, manufacturing strategy, overlap and material influences on the most characteristic 3D surface parameters. The results are based on ANOVA – analysis of variance, where differences between groups of means are analysed using a range of statistical models. Subsequent analysis and respective conclusions identify the most significant factors as being the material and high-speed milling manufacturing strategy. Analytically justified recommendations for manufacturers regarding the preferred high-speed milling strategies are provided. The research concluded that the values of the selected 3D surface roughness parameters in high-speed milling depend significantly on the type of material being machined, milling mode and cutting tool overlap as well as feed. In particular, Sa - the arithmetic mean height, is highly sensitive to the milling mode.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

The Impact of High-Speed Rail on the Spatial Structure of Chinese Urban Agglomerations

2020 ◽  
Vol 46 (3) ◽  
pp. 379-397
Author(s):  
Chunyang Wang
Keyword(s):  
High Speed ◽  
River Delta ◽  
City Size ◽  
High Speed Rail ◽  
Local Conditions ◽  
Urban Agglomerations ◽  
Large Cities ◽  
Spatial Systems ◽  
Economic Concentration ◽  
The Impact

This paper measures the spatial evolution of urban agglomerations to understand be er the impact of high-speed rail (HSR) construction, based on panel data from fi ve major urban agglomerations in China for the period 2004–2015. It is found that there are signi ficant regional diff erences of HSR impacts. The construction of HSR has promoted population and economic diff usion in two advanced urban agglomerations, namely the Yang e River Delta and Pearl River Delta, while promoting population and economic concentration in two relatively less advanced urban agglomerations, e.g. the middle reaches of the Yang e River and Chengdu–Chongqing. In terms of city size, HSR promotes the economic proliferation of large cities and the economic concentration of small and medium-sized cities along its routes. HSR networking has provided a new impetus for restructuring urban spatial systems. Every region should optimize the industrial division with strategic functions of urban agglomeration according to local conditions and accelerate the construction of inter-city intra-regional transport network to maximize the eff ects of high-speed rail across a large regional territory.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

scholarly journals The impact of inelastic self-interacting dark matter on the dark matter structure of a Milky Way halo

2020 ◽  
Author(s):  
Kun Ting Eddie Chua ◽  
Karia Dibert ◽  
Mark Vogelsberger ◽  
Jesús Zavala
Keyword(s):  
Dark Matter ◽  
High Speed ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Direct Detection ◽  
Major Axis ◽  
Inelastic Collisions ◽  
Axis Ratio ◽  
Lower Velocity ◽  
The Impact

Abstract We study the effects of inelastic dark matter self-interactions on the internal structure of a simulated Milky Way (MW)-size halo. Self-interacting dark matter (SIDM) is an alternative to collisionless cold dark matter (CDM) which offers a unique solution to the problems encountered with CDM on sub-galactic scales. Although previous SIDM simulations have mainly considered elastic collisions, theoretical considerations motivate the existence of multi-state dark matter where transitions from the excited to the ground state are exothermic. In this work, we consider a self-interacting, two-state dark matter model with inelastic collisions, implemented in the Arepo code. We find that energy injection from inelastic self-interactions reduces the central density of the MW halo in a shorter timescale relative to the elastic scale, resulting in a larger core size. Inelastic collisions also isotropize the orbits, resulting in an overall lower velocity anisotropy for the inelastic MW halo. In the inner halo, the inelastic SIDM case (minor-to-major axis ratio s ≡ c/a ≈ 0.65) is more spherical than the CDM (s ≈ 0.4), but less spherical than the elastic SIDM case (s ≈ 0.75). The speed distribution f(v) of dark matter particles at the location of the Sun in the inelastic SIDM model shows a significant departure from the CDM model, with f(v) falling more steeply at high speeds. In addition, the velocity kicks imparted during inelastic collisions produce unbound high-speed particles with velocities up to 500 km s−1 throughout the halo. This implies that inelastic SIDM can potentially leave distinct signatures in direct detection experiments, relative to elastic SIDM and CDM.

scholarly journals Influence of Whey Protein Micro-Gel Particles and Whey Protein Micro-Gel Particles-Xanthan Gum Complexes on the Stability of O/W Emulsions

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2301
Author(s):  
Man Zhang ◽  
Bin Liang ◽  
Hongjun He ◽  
Changjian Ji ◽  
Tingting Cui ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Whey Protein ◽  
High Speed ◽  
Xanthan Gum ◽  
Physical Stability ◽  
Theoretical Support ◽  
Gel Particles ◽  
Oil In Water ◽  
The Stability ◽  
The Impact

Appropriate pretreatment of proteins and addition of xanthan gum (XG) has the potential to improve the stability of oil-in-water (O/W) emulsions. However, the factors that regulate the enhancement and the mechanism are still not clear, which restricts the realization of improving the emulsion stability by directional design of its structure. Therefore, the effects of whey protein micro-gel particles (WPMPs) and WPMPs-XG complexes on the stability of O/W emulsion were investigated in this article to provide theoretical support. WPMPs with different structures were prepared by pretreatment (controlled high-speed shear treatment of heat-set WPC gels) at pH 3.5–8.5. The impact of initial WPC structure and XG addition on Turbiscan Indexes, mean droplet size and the peroxide values of O/W emulsions was investigated. The results indicate that WPMPs and XG can respectively inhibit droplet coalescence and gravitational separation to improve the physical stability of WPC-stabilized O/W emulsions. The pretreatment significantly enhanced the oxidative stability of WPC-stabilized O/W emulsions. The addition of XG did not necessarily enhance the oxidative stability of O/W emulsions. Whether the oxidative stability of the O/W emulsion with XG is increased or decreased depends on the interface structure of the protein-XG complex. This study has significant implications for the development of novel structures containing lipid phases that are susceptible to oxidation.

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