Journal of Mechanical Science and Technology 32 (10) (2018) 4621~4628
www.springerlink.com/content/1738-494x(Print)/1976-3824(Online)
DOI 10.1007/s12206-018-0909-y
A study on life evaluation & prediction of railway vehicle contactor based on
accelerated life test data
†
Minheung Park and Sehun Rhee
*
Department of Mechanical Convergence Engineering, Hanyang University, Seoul 133-791, Korea
(Manuscript Received July 6, 2017; Revised May 18, 2018; Accepted July 6, 2018)
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Abstract
In this recent tendency, an accelerated life test (ALT) is used to evaluate stability and reliability of machinery parts and systems for
short periods. As ALT is performed by applying high stress compared to normal use conditions in a short time, we can rapidly evaluate
the life of the machinery and obtain reliability values. In this paper, we conduct the accelerated life test for a railway vehicle contactor,
constructing the real-time monitoring system. Based on ALT data, we can determine the contactor's failure mode and mechanism, and
estimate reliability values. Consequently, we will examine the method of evaluating the life of railway vehicle contactors through an
estimation of the interesting value - relationship between life and stress, mean time to failure (MTTF), percentile B
100P
life etc. in normal
use conditions.
Keywords: Accelerated life test; Arrhenius Weibull model; Statistical analysis; Life evaluation & prediction; Railway vehicle contactor
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1. Introduction
As interest in product reliability rise, manufacturers are in-
creasingly in need of a product reliability assessment. The
accelerated life test (ALT) is an effective test method used to
evaluate reliability, including factors such as product life and
performance. ALT is a test technique used to evaluate the
stability and reliability of components or systems within a
short time. A stronger stress will be applied to evaluate the
reliability and failure rate of a product within a very short time.
The life of the product can be predicted using the obtained
accelerated life test data and accelerated life model. Nelson
reviewed the life distribution and acceleration model for
reliability analysis and systematically presented the data
analysis methodology and the basic theories that were
obtained through ALT under single stress, step stress and
various stress conditions [1]. Meeker and Escobar also
introduced ALT models, test methods, and test plans in his
book [2]. Pascual et al. presented accelerated models,
including guidance for their applications, and introduced
examples of ALT data analysis [3]. In addition, Elsayed
studied test planning and design for reliability testing,
estimation, model prediction, and the acquisition of failure and
degradation data [4, 5]. Choi et al. predicted the life of BPHE
(brazed plate heat exchanger) based on data obtained from
ALT [6]. Turner proposed a methodology to describe
quantitative ALT in power systems [7]. Choi et al. estimated
the reliability of the TEM (thermo-electric module) through
ALT and the analysis of failure physics [8]. Lee et al.
proposed a complex acceleration model considering the
pressure and temperature of the hose assembly through ALT
[9]. Ismail estimated the unknown parameters through the
maximum likelihood method by Newton–Raphson algorithm
under step-stress partially accelerated test model [10].
According to research trends related to contactor, Li et al.
proposed a method to reduce the mechanical failure of relays
using contact reed's design dimensions through a reliability
test and the analysis of electro-magnetic relay [11]. Lu et al.
proposed the reliability test method with the over-load relay.
The current used for the relay was 1.05, 1.2, 1.5, 7.2 times
higher than the current used for the conventional system and
they observed the state of the relay at that time [12]. Li et al.
studied the electrical property test, seal test, scanning electron
microscope, x-ray energy dispersive spectroscopy and x-ray
photoelectron spectroscopy in the failure analysis of
electromagnetic relay contacts. They investigated the
relationship between the failure and the increase of the
resistance value at the contaminated contact zone [13]. Ryu et
al. studied the warranty life of products through ALT using
the rated current for the magnetic switch used in the power
distribution system [14]. Almost all researches are based on
surface of contact zone or electrical stress test. However, envi-
ronmental effect were not considered for evaluation or predic-
*
Corresponding author. Tel.: +82 2 2220 0438, Fax.: +82 2 2299 6040
E-mail address: srhee@hanyang.ac.kr
†
Recommended by Editor Chongdu Cho
© KSME & Springer 2018
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