scholarly journals Informativity of the Vibration Signal of the Spindle Unit of the Metal Cutting Machine

2021 ◽  
Vol 346 ◽  
pp. 03043
Author(s):  
Alexander Denisenko ◽  
Viktor Mikhailov
Keyword(s):  
Energy Balance ◽  
Power Flow ◽  
Metal Cutting ◽  
Early Stage ◽  
Vibration Signal ◽  
Balance Equations ◽  
Vibration Field ◽  
Spindle Unit ◽  
Urgent Task ◽  
Vibration Power Flow

Monitoring the condition of the spindle units of modern metal-cutting machines by methods of non-selective diagnostics involves the possibility of installing monitoring sensors in places with maximum vibration information. In this regard, the assessment of the informative value of the vibration field of the spindle unit, which can be carried out in advance, taking into account the design features, geometric and dimensional characteristics, is an urgent task. Based on the energy approach, a computational model based on the median planes of the walls is proposed using the example of a universal lathe spindle unit. On the basis of the calculated model, the energy balance equations are drawn up taking into account the conditions for the transmission of vibration power between the walls of the housing. The dependences that allow us to calculate the coefficients that take into account the absorption of vibration energy by the walls of the housing are given. The solution of the energy balance equations made it possible, based on the level of the vibration power flow, to rank the walls of the spindle unit body by information content,. The resulting model of the vibration field can be used to determine the reference values of vibration velocities that are formed from sources in the absence of defects. This will allow for non-selective diagnostics to detect the occurrence of a defect at an early stage, and in the presence of a defect to assess the level of its development.

scholarly journals DETERMINATION OF VIBRATION POWER OF VIBRATION SOURCES OF SPINDLE UNITS OF METAL CUTTING MACHINES

2021 ◽  
Vol 23 (3) ◽  
pp. 55-61
Author(s):  
A.F. Denisenko ◽  
◽  
V.V. Mikhailov ◽  
Keyword(s):  
Metal Cutting ◽  
Center Of Mass ◽  
Spindle Assembly ◽  
Vibration Field ◽  
Spindle Unit ◽  
Urgent Task ◽  
Parametric Reliability ◽  
Calculated Model ◽  
Spindle Assemblies

Monitoring the state of spindle assemblies of modern metal-cutting machines using CIP methods implies the possibility of installing control sensors in places with maximum vibration information content. In this regard, the assessment of the informativeness of the vibration field of the spindle assembly, which can be carried out in advance, taking into account the design features, geometric and dimensional characteristics, is an urgent task. Based on the energy approach, using the example of the spindle assembly of a universal lathe, a computational model is proposed, built along the median planes of the walls. On the basis of the calculated model, the equations of the energy balance were compiled taking into account the conditions for the transfer of vibration power between the walls of the housing. The method for determining the vibration power of the main sources in the spindle assemblies is given: a spindle with residual unbalance, a drive gear and bearings. It has been established that the most significant factors determining the vibration power introduced into the spindle unit housing are the operation of the bearings, the weight of the spindle and the location of its center of mass. The result obtained makes it possible to detect incipient defects in the bearings, which, as practice shows, are the defining elements of the parametric reliability of spindle assemblies. The resulting model of the vibration field can be used to determine the reference values of vibration velocities that are formed from sources in the absence of defects.

Statistical Energy Analysis for the Time-Integrated Transient Response of Vibrating Systems

1990 ◽  
Vol 112 (2) ◽  
pp. 206-213 ◽  
Author(s):  
M. L. Lai ◽  
A. Soom
Keyword(s):  
Steady State ◽  
Energy Balance ◽  
Transient Response ◽  
Power Flow ◽  
Energy Analysis ◽  
Statistical Energy Analysis ◽  
Balance Equations ◽  
Integrated Response ◽  
Energy Relations ◽  
Loss Factors

For more than twenty years, statistical energy analysis (SEA) has been used for the analysis of steady-state response distributions in complex coupled structures and sound-structure systems. However, the steady-state SEA formalism is not directly applicable to the analysis of transient vibrations. In this paper, energy relations, analogous to steady-state SEA power flow relations, are derived for the time-integrated transient response of each oscillator. These energy flow relations can be combined using statistical concepts, to obtain a set of energy balance equations for N coupled multimodal subsystems. It is shown that the time-integrated response of each subsystem can be described in terms of transient input energies and conventional SEA parameters, i.e., modal densities, loss factors and coupling loss factors. By solving the energy balance equations, the time-integrated response of each subsystem can be obtained. The results of experiments, conducted on a coupled structure consisting of two welded plates, are presented to illustrate the applicability of these relations.

Effects of Ambipolar Diffusion on Prominence Thread Models

1994 ◽  
Vol 144 ◽  
pp. 315-321 ◽  
Author(s):  
M. G. Rovira ◽  
J. M. Fontenla ◽  
J.-C. Vial ◽  
P. Gouttebroze
Keyword(s):  
Energy Balance ◽  
Transition Region ◽  
Ambipolar Diffusion ◽  
Line Profiles ◽  
Balance Equations ◽  
Model Calculations ◽  
Partial Frequency ◽  
Frequency Redistribution ◽  
Partial Frequency Redistribution ◽  
Theoretical Structure

AbstractWe have improved previous model calculations of the prominence-corona transition region including the effect of the ambipolar diffusion in the statistical equilibrium and energy balance equations. We show its influence on the different parameters that characterize the resulting prominence theoretical structure. We take into account the effect of the partial frequency redistribution (PRD) in the line profiles and total intensities calculations.

Parametric Study of Photovoltaic Thermal Solar Collector Using An Improved Parallel Flow

2020 ◽  
Vol 2 (1) ◽  
pp. 19-24
Author(s):  
Sakhr Mohammed Sultan ◽  
Chih Ping Tso ◽  
Ervina Efzan Mohd Noor ◽  
Fadhel Mustafa Ibrahim ◽  
Saqaff Ahmed Alkaff
Keyword(s):  
Thermal Conductivity ◽  
Energy Balance ◽  
Parametric Study ◽  
Solar Collector ◽  
Parallel Flow ◽  
Operating Conditions ◽  
Balance Equations ◽  
Conductivity Type ◽  
Pv Module ◽  
Sunny Weather

Photovoltaic Thermal Solar Collector (PVT) is a hybrid technology used to produce electricity and heat simultaneously. Current enhancements in PVT are to increase the electrical and thermal efficiencies. Many PVT factors such as type of absorber, thermal conductivity, type of PV module and operating conditions are important parameters that can control the PVT performance. In this paper, an analytical model, using energy balance equations, is studied for PVT with an improved parallel flow absorber. The performance is calculated for a typical sunny weather in Malaysia. It was found that the maximum electrical and thermal efficiencies are 12.9 % and 62.6 %, respectively. The maximum outlet water temperature is 59 oC.

Structure-Borne Power Transmission in Thin Naturally Orthotropic Plates: General Case

2003 ◽  
Vol 9 (10) ◽  
pp. 1189-1199 ◽  
Author(s):  
Nirmal Kumar Mandal ◽  
Roslan Abd. Rahman ◽  
M. Salman Leong
Keyword(s):  
Fourier Transform ◽  
Power Flow ◽  
Power Transmission ◽  
Far Field ◽  
Orthotropic Plates ◽  
Flow Estimation ◽  
Structural Intensity ◽  
Vibration Power Flow ◽  
Conventional Idea ◽  
Bending Wave

The structural intensity technique is usually used to estimate vibration power flow in structures. This method is used to determine vibration power flow in thin naturally orthotropic plates. The bending wave is considered to find general vibration power transmission in the frequency domain that is not approximated by far field conditions. This intensity formulation defines power flow per unit width of the plates (W m−1) similar to that of the conventional idea. Power flow estimation is formulated using cross-spectra of field signals, facilitating the use of a fast Fourier transform analyzer.

The Efficiency of Tidal Fences: A Brief Review and Further Discussion on the Effect of Wake Mixing

2013 ◽  
Author(s):  
Takafumi Nishino ◽  
Richard H. J. Willden
Keyword(s):  
Energy Balance ◽  
Theoretical Investigation ◽  
Three Dimensional ◽  
Physical Factors ◽  
Balance Equations ◽  
Order Model ◽  
Near Wake ◽  
New Model ◽  
Actuator Disk ◽  
Limiting Efficiency

Recent discoveries on the limiting efficiency of tidal fences are reviewed, followed by a new theoretical investigation into the effect of wake mixing on the efficiency of ‘full’ tidal fences (i.e. turbines arrayed regularly across an entire channel span). The new model is based on the momentum and energy balance equations but includes several unclosed terms, which depend on the actual (three-dimensional) characteristics of turbine near-wake mixing and therefore need to be modelled empirically. The new model agrees well with three-dimensional actuator disk simulations when those unclosed terms are assessed based on the simulations themselves, suggesting that this low-order model could serve as a basis to analyse how various physical factors (such as the design of turbines) affect the limiting efficiency of tidal fences via changes in those terms describing the characteristics of turbine near-wake mixing. Also discussed is the effect of wake mixing on the efficiency of ‘partial’ tidal fences.

Research on Vibration Isolation Parameters of Double-Deck Isolation System of Heat Water Pump

2013 ◽  
Vol 694-697 ◽  
pp. 316-320
Author(s):  
Xiang Jun Kong ◽  
Er Ming Song ◽  
Chang Zheng Chen
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Mass Effect ◽  
Transmitted Power ◽  
Intermediate Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Upper Deck ◽  
Vibration Power Flow

Isolation system of the heat water pumps can be simplified as a double sources exciting and double output double-deck vibration isolation system model, expressions of transmitted power flow and vibration speed to the basement are deduced based on the double sources exciting and double output double-deck vibration isolation system electric-force(E-F) analog picture, the curves of power flow and vibration speed transmitted to basement how the upper deck vibration isolation and intermediate mass effect are drawn by using mat lab program. The results show that the adjusting the upper deck vibration isolation stiffness parameters has little effect on the amplitude of vibration power flow, increasing intermediate mass can move first peak to the low frequency, increasing intermediate mass can obviously reduce t transmitted power flow and transmitted vibration speed amplitude to the basement.

scholarly journals Linear power-flow analysis method for AC-DC electric power networks

2021 ◽  
Author(s):  
Mohammadreza Vatani
Keyword(s):  
Power Systems ◽  
Linear Model ◽  
Power Flow ◽  
Linear Models ◽  
Power Converters ◽  
Power Balance ◽  
Balance Equations ◽  
Dc Power ◽  
Phase Angles ◽  
Dc Power Systems

AC-DC power systems have been operating more than sixty years. Nonlinear bus-wise power balance equations provide accurate model of AC-DC power systems. However, optimization tools for planning and operation require linear version, even if approximate, for creating tractable algorithms, considering modern elements such as DERs (distributed energy resources). Hitherto, linear models of only AC power systems are available, which coincidentally are called DC power flow. To address this drawback, linear bus-wise power balance equations are developed for AC-DC power systems and presented. As a first contribution, while AC and DC lines are represented by susceptance and conductance elements, AC-DC power converters are represented by a proposed linear relationship. As a second contribution, a three-step linear AC-DC power flow method is proposed. The first step solves the whole network considering it as a linear AC network, yielding bus phase angles at all busses. The second step computes attributes of the proposed linear model of all AC-DC power converters. The third step solves the linear model of the AC-DC system including converters, yielding bus phase angles at AC busses and voltage magnitudes at DC busses. The benefit of the proposed linear power flow model of AC-DC power system, while an approximation of the nonlinear model, enables representation of bus-wise power balance of AC-DC systems in complex planning and operational optimization formulations and hence holds the promise of phenomenal progress. The proposed linear AC-DC power systems is tested on numerous IEEE test systems and demonstrated to be fast, reliable, and consistent.

Sign in / Sign up

Export Citation Format

Share Document