Evaluation for machine tool components importance based on improved LeaderRank

2020 ◽  
pp. 1748006X2097943
Author(s):  
Yingzhi Zhang ◽  
Shubin Liang ◽  
Jialin Liu ◽  
Peilong Cao ◽  
Lan Luan
Keyword(s):  
Machine Tool ◽  
Time Correlation ◽  
Fault Model ◽  
Time Variability ◽  
Fault Propagation ◽  
Machine Maintenance ◽  
Maintenance Cycle ◽  
Dynamic Time ◽  
Fault Information ◽  
Transfer Probability

The existence of the failure transitivity of machine tool components makes the fault transfer probability of components demonstrate dynamic time-variability, which affects the importance of components and further affects the machine maintenance cycle. Therefore, studying fault transfer probability and the importance of machine tool components is necessary. In this article, the fault transfer probability of component is defined according to component fault propagation directed graph and component independent fault and related fault model based on time correlation. Assuming that the fault propagation follows the Markov process, the improved LeaderRank algorithm is applied to evaluate the importance of components by introducing background node and calculating failure impact degree of component on the basis of out-degree. Finally, the specific application is verified by taking the fault information of a certain type of machine as an example.

Radiation from supersonic faulting

1971 ◽  
Vol 61 (4) ◽  
pp. 1009-1012 ◽  
Author(s):  
J. C. Savage
Keyword(s):  
Initial Point ◽  
Step Function ◽  
Fault Model ◽  
Dislocation Segment ◽  
Far Field ◽  
Fault Propagation ◽  
Unit Step ◽  
Propagation Factor ◽  
Double Couple ◽  
Field Radiation

abstract The far-field radiation from a simple fault model is given by the radiation pattern associated with the appropriate strain nucleus (e.g., double couple) multiplied by a fault propagation factor. For a unilateral fault model the propagation factor is F ( c ; t ) = ζ bd [ H ( τ ) − H ( τ − ( L / ζ ) ( 1 − ( ζ / c ) cos ψ )) ] / ( 1 − ( ζ / c ) cos ψ ) where ξ is the velocity of fault propagation, b is the fault slip, d is the fault width, τ = t − r0/c, r0 is the distance of the observer from the initial point of faulting, c is the velocity of the seismic wave, H(τ) is the unit-step function, L is the length of the fault, and ψ the angle between r0 and the direction of fault propagation. This representation is valid for both subsonic and supersonic fault propagation. The latter case is important because Weertman (1969) has recently shown that spontaneous faulting may propagate at supersonic velocities. Because the propagation factor is always positive, the nodal planes for the radiation are the same as for the appropriate strain nucleus. Finally, it is shown by the application of this equation that the radiation from a screw dislocation segment is represented by the double-couple nucleus, not the compensated linear-vector dipole nucleus as recently suggested by Knopoff and Randall (1970).

Preventive Maintenance Optimization of Availability for NC Machine

2014 ◽  
Vol 988 ◽  
pp. 653-658
Author(s):  
Gang Lei ◽  
Chao Deng ◽  
Bo Sheng
Keyword(s):  
Probability Density Function ◽  
Machine Tool ◽  
Preventive Maintenance ◽  
Maintenance Optimization ◽  
Maintenance Strategy ◽  
Maintenance Period ◽  
Nc Machine Tool ◽  
Nc Machine ◽  
Function Module ◽  
Fault Information

This paper addresses the problem of preventive maintenance optimization for NC machine tool. Firstly, the NC machine tool is divided into four subsystems according to the function module. The failure probability density function of each subsystem is estimated with the fault information records. Then, the optimal preventive maintenance period is estimated for each subsystem considering the availability. The optimal periods of all the subsystems are used to derive the preventive maintenance strategy of the whole machine. Finally, a numerical case is presented and the result shows the performance of the proposed approach.Keywords: NC machine tool, subsystem, availability, preventive maintenance

scholarly journals Reliability allocation of rotary ultrasonic vibration-assisted EDM machine tool based on maximum entropy ordered weighted average and constraint under the index of overall cost

2021 ◽  
Author(s):  
Minggang Xu ◽  
Hao Fu ◽  
Wang Tian ◽  
Binbin Lyu ◽  
Zihao Jiang ◽  
...  
Keyword(s):  
Machine Tool ◽  
Maximum Entropy ◽  
Ultrasonic Vibration ◽  
Cost Optimization ◽  
Weighted Average ◽  
Effective Control ◽  
Maintenance Cost ◽  
Optimum Number ◽  
Maintenance Cycle ◽  
Ordered Weighted Average

Abstract Rotary ultrasonic vibration-assisted EDM is a composite machining method which uses EDM technology to process metal surface and adds rotation and ultrasonic vibration. In this paper, the failure rate of each module of the rotary ultrasonic vibration-assisted EDM machine tool can be accurately predicted by the maximum entropy ordered weighted average algorithm so that the corrected maintenance cost can be predicted. And effective control of preventive maintenance costs can be achieved by selecting the best maintenance times under the premise of reliability. The results showed that the reliability of rotary ultrasonic vibration-assisted EDM machine tool is smoother at non-fixed maintenance intervals by varying the maintenance interval according to the comparison between non-fixed and fixed maintenance cycle. The cost of corrective maintenance can be reduced by varying the measurement to achieve cost optimization in the context of reliability with an optimum number of maintenance cycles and reliability.

Low leverage policy: a boon or bane for Indian shareholders

2018 ◽  
Vol 12 (4) ◽  
pp. 489-507 ◽  
Author(s):  
Soumya G. Deb ◽  
Pradip Banerjee
Keyword(s):  
Operating Performance ◽  
Balance Sheet ◽  
Equity Market ◽  
Time Variability ◽  
Financial Flexibility ◽  
Content Type ◽  
Tax Shield ◽  
Incremental Value ◽  
Potential Benefits ◽  
Dynamic Time

Purpose This paper aims to explore whether following an apparently sub-optimal “almost zero leverage (AZL)” policy by some Indian firms actually creates incremental value for their shareholders or is detrimental for them. Design/methodology/approach The paper investigates the relative equity market and operating performance of a sample of Indian firms adopting an AZL policy between 1998 and 2014, vis-a-vis, their leveraged peers from the same industry. The authors also look at the dynamic time variability of patterns, if any, in such relative performance and explore whether such patterns are explained primarily by investor perceptions or there are other factors to it. Findings The study show that Indian firms following post AZL policy exhibit superior equity performance compared to their leveraged counterparts, particularly during market downturns. The authors also find that this superior equity market performance is not merely because of the positive investor perception about the potential benefits of a robust debt-free balance sheet. The authors’ results show that the AZL firms register higher business risk and significantly superior operating performance, post being low leverage. The results hold even after using several robustness checks. Practical implications The study concludes that the managers of AZL firms take full advantage of the increased financial flexibility available with them and venture into riskier but more rewarding avenues and actually create incremental value for their shareholders. Originality/value The study highlights an apparently counterintuitive pattern in Indian context, counterintuitive particularly because choosing an AZL policy leads to forgo the availability of significant tax shield for firms. The results, the authors believe, can have significant implications for lenders and investors in the Indian capital markets in particular and emerging markets in general.

scholarly journals Uncertainty Approaches for Solving Generalized Machine Maintenance Problem

2020 ◽  
Vol 5 (6) ◽  
pp. 675-682
Author(s):  
Samir Abdou Abass ◽  
Asmaa S. Abdallah ◽  
Marwa Shehata Elsayed ◽  
Eman Massoud Ahmed
Keyword(s):  
Optimization Problems ◽  
Programming Model ◽  
Uncertain Data ◽  
Real Life ◽  
Fuzzy Programming ◽  
Machine Maintenance ◽  
Interval Approach ◽  
Maintenance Cycle ◽  
Rough Interval ◽  
Maintenance Problem

In this paper, the generalized machine maintenance problem is formulated as linear programming model. The objective is to maximize the percentage production hours available per maintenance cycle of each machine.  Data in many real life engineering and economic problems suffers from inexactness. There are different approaches to deal with uncertain optimization problems. In this paper two different approaches of uncertainty, Fuzzy programming and rough interval programming approaches will be introduced. We deal the concerned problem with uncertain data in coefficients of the constraints for the two approaches. A numerical example is introduced to clarify the two proposed approaches. A comparison study between the obtained results of the two proposed approaches and the results of interval approach for Samir A. and Marwa Sh [3] will be introduced.

scholarly journals Risk Analysis of Coupling Fault Propagation Based on Meta-Action for Computerized Numerical Control (CNC) Machine Tool

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yifan Chen ◽  
Genbao Zhang ◽  
Yan Ran
Keyword(s):  
Machine Tool ◽  
Fault Analysis ◽  
Propagation Model ◽  
Numerical Control ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Fault Propagation ◽  
Coupling Relationship ◽  
Coupling Fault ◽  
Fault Propagation Model

A comprehensive fault analysis of CNC machine tool is conducive to improving its reliability. Due to the highly complex structure of CNC machine tool, there are different degrees of coupling relationship between faults. However, the traditional fault analysis methods (FMEA, FTA, etc.) for CNC machine tool do not solve this problem perfectly. Therefore, we propose a coupling fault propagation model based on meta-action. First, in order to simplify the structural complexity of CNC machine tool, the “Function-Motion-Action (FMA)” decomposition structure is used to decompose the product function into simple meta-action, and the numerical matrix is used to quantify the coupling relationship between the meta-actions. Then, based on the fault transfer characteristics of meta-action, the fault propagation model is established, and the global risk effect (GRE) is combined to realize the comprehensive evaluation of the risk criticality of meta-actions. Finally, the rationality and validity of the method are verified by the case analysis of the automatic pallet changer (APC) of computerized numerical control (CNC) machining center.

scholarly journals Characteristic time variability of gravitational-wave and neutrino signals from three-dimensional simulations of non-rotating and rapidly rotating stellar core collapse

2021 ◽  
Vol 502 (2) ◽  
pp. 3066-3084
Author(s):  
Shota Shibagaki ◽  
Takami Kuroda ◽  
Kei Kotake ◽  
Tomoya Takiwaki
Keyword(s):  
Characteristic Time ◽  
Three Dimensional ◽  
Time Correlation ◽  
Time Variability ◽  
Core Collapse ◽  
Spiral Flow ◽  
Initial Strength ◽  
Stellar Core ◽  
The Impact ◽  
Armed Spiral

ABSTRACT We present results from full general relativistic 3D hydrodynamics simulations of stellar core collapse of a 70 M⊙ star with spectral neutrino transport. To investigate the impact of rotation on non-axisymmetric instabilities, we compute three models by parametrically changing the initial strength of rotation. The most rapidly rotating model exhibits a transient development of the low-T/|W| instability with one-armed spiral flow at the early post-bounce phase. Subsequently, the two-armed spiral flow appears, which persists during the simulation time. The moderately rotating model also shows the growth of the low-T/|W| instability, but only with the two-armed spiral flow. In the non-rotating model, a vigorous activity of the standing accretion-shock instability (SASI) is only observed. The SASI is first dominated by the sloshing mode, which is followed by the spiral SASI until the black hole (BH) formation. We present a spectrogram analysis of the gravitational waves (GWs) and neutrinos, focusing on the time correlation. Our results show that characteristic time modulations in the GW and neutrino signals can be linked to the growth of the non-axisymmetric instabilities. We find that the degree of the protoneutron star (PNS) deformation, depending upon which modes of the non-axisymmetric instabilities develop, predominantly affects the characteristic frequencies of the correlated GW and neutrino signals. We point out that these signals would be simultaneously detectable by the current-generation detectors up to ∼10 kpc. Our findings suggest that the joint observation of GWs and neutrinos is indispensable for extracting information on the PNS evolution preceding the BH formation.

Application of fault propagation intensity in fault diagnosis of CNC machine tool

2019 ◽  
Vol 43 (2) ◽  
pp. 153-161
Author(s):  
Yingzhi Zhang ◽  
Liming Mu ◽  
Jialin Liu ◽  
Jintong Liu ◽  
Zhifu Tian ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
Machine Tool ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Fault Propagation

scholarly journals A failure detector for HPC platforms

2017 ◽  
Vol 32 (1) ◽  
pp. 139-158 ◽  
Author(s):  
George Bosilca ◽  
Aurelien Bouteiller ◽  
Amina Guermouche ◽  
Thomas Herault ◽  
Yves Robert ◽  
...  
Keyword(s):  
National Laboratory ◽  
Overlay Network ◽  
Circulant Graph ◽  
Failure Detector ◽  
Fault Propagation ◽  
Single Node ◽  
Oak Ridge ◽  
Virtual Observation ◽  
Fault Information ◽  
Propagation Stage

Building an infrastructure for exascale applications requires, in addition to many other key components, a stable and efficient failure detector. This article describes the design and evaluation of a robust failure detector that can maintain and distribute the correct list of alive resources within proven and scalable bounds. The detection and distribution of the fault information follow different overlay topologies that together guarantee minimal disturbance to the applications. A virtual observation ring minimizes the overhead by allowing each node to be observed by another single node, providing an unobtrusive behavior. The propagation stage uses a nonuniform variant of a reliable broadcast over a circulant graph overlay network and guarantees a logarithmic fault propagation. Extensive simulations, together with experiments on the Titan Oak Ridge National Laboratory supercomputer, show that the algorithm performs extremely well and exhibits all the desired properties of an exascale-ready algorithm.

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