Reliability Test Program Research Articles

Compilation of load spectrum of CNC machine tools reliability test program based on Weibull kernel function

The load spectrum is the foundational data for reliability tests that simulate actual working conditions. Determining typical working conditions and accurate load extrapolation are the key to the load spectrum. This paper proposes a method for compiling the load spectrum of a reliability test program of CNC machine tools based on Weibull kernel function. The aforementioned method aims to address the issues commonly encountered in the load spectrum, such as complex factors that affect typical working conditions, heterogeneous load data of working conditions, and reliance on assumption distribution during load extrapolation. The method involves a determination process for typical working conditions using the Weibull kernel function and a non-parametric load extrapolation method based on kernel function. Firstly, this paper proposes a kernel density estimation method based on Weibull kernel function to address the issues of probability density contribution value deviation caused by the inconsistency between the conventional kernel function symmetry and the off-peak characteristic of load. The approach is based on the physical meaning and generalization of the Weibull distribution parameters and is used to determine the typical working conditions of CNC machine tools. Secondly, this paper proposes a nonparametric rainflow extrapolation method for cutting loads of CNC machine tools based on two-dimensional kernel density estimation. The approach takes advantage of the nonparametric rainflow extrapolation method and considers the characteristics of the cutting load. And the load spectrum of the three-dimensional cutting force of the CNC machine tool is constructed using the mean-range probability density distribution of the cutting load. Finally, the reliability test program loading spectrum of CNC machine tools is determined using the Conover ratio coefficient. Through case analysis, it can be known that the nuclear density estimation method proposed in this paper can improve the compilation accuracy of the load spectrum and has practical application significance.

Mechanical Insertion and Reliability Testing of Thermal Interface Materials for Semiconductor Test and Burn-in Applications

Abstract Very challenging requirements exist for thermal interface materials (TIMs) for demanding applications I semiconductor testing. Reliability requirements and multiple contact cycling requirements are substantially different and do not exist in traditional applications for TIMs. Developing new material types to meet these very exacting and unusual requirements has been a long-term goal and requires development of an unusual series of test procedures to demonstrate whether the desired reliability goals have been met. Use of a servo-driven, commercial test stand that has unique features for operation and control is described as the basis for a reliability and performance test program developed for these new materials in three phases, with new data for a fourth test phase added, and comparative values for material performance.

Symbolic Time-Series Analysis of Gas Turbine Gas Path Electrostatic Monitoring Data

The aero-engine gas-path electrostatic monitoring system is capable of providing early warning of impending gas-path component faults. In the presented work, a method is proposed to acquire signal sample under a specific operating condition for on-line fault detection. The symbolic time-series analysis (STSA) method is adopted for the analysis of signal sample. Advantages of the proposed method include its efficiency in numerical computations and being less sensitive to measurement noise, which is suitable for in situ engine health monitoring application. A case study is carried out on a data set acquired during a turbojet engine reliability test program. It is found that the proposed symbolic analysis techniques can be used to characterize the statistical patterns presented in the gas path electrostatic monitoring data (GPEMD) for different health conditions. The proposed anomaly measure, i.e., the relative entropy derived from the statistical patterns, is confirmed to be able to indicate the gas path components faults. Finally, the further research task and direction are discussed.

A simulation-based approach to determine the evaluation adequacy of system-of-systems operational test configurations

A system-of-systems is defined as “a set or arrangement of systems that results from independent systems integrated into a larger system that delivers unique capabilities.” Given practical resource constraints, it is rare that the full-field configuration of the system-of-systems can be exercised during an operational reliability demonstration test. However, as we consider various potential operational test configurations for a given system-of-systems during the reliability test program planning process, it is critical to understand how testing a configuration that is smaller than the full-field configuration decreases the adequacy of the test by reducing the accuracy of the system-of-systems’ reliability estimate that is based on the test results. Thus, it is useful to assess the adequacy of potential system-of-systems’ operational test configurations before adopting one. We present a novel simulation-based method that can be employed to assess the adequacy of a given test configuration for any type of system-of-systems. To illustrate how this simulation-based method can be used to aid in the identification of the best alternative from among a group of potential operational test configuration alternatives, we include an example application using a notional air defense system-of-systems. Trade-offs with respect to cost, schedule, and accuracy are addressed within the context of this application.

Experiences from reliability testing of aircraft electronic equipment

Some important details of creation and realization of a test program for the mean time between failures for fighter aircraft electronic equipment are discussed. Experiences from such a reliability testing program, concerning the calculated and required mean time between failures and choosing a proper test plan, are summarized. The conclusion stresses the importance of the calculation of the mean time between failures before testing.

A new method and apparatus for evaluation of the K-slump of concrete

This paper introduces a new digital model of the K-slump tester. For the new tester (patent pending), it is theoretically shown that an inverse linear relationship exists between the K-slump of freshly mixed concrete or mortar and the yield stress τ0 in the Bingham model. The validity of this relation was investigated experimentally. Tests were conducted on cement pastes, mortar, and fresh concrete mixtures using a Hobart food mixer and the new tester. Power consumed by the mixer at three different speeds was measured along with the K-slumps for fresh concrete mixtures. The results give excellent agreement with the theoretically derived relationship. Hence, the K-slump of concrete was shown to be related to the yield stress τ0 by the equation K = Kmax − (constant × τ0), where Kmax is the maximum K-slump. To determine the precision of the new tester, an interoperator reliability test program was carried out in accordance with ASTM designation C 802. The results indicate that the new apparatus is accurate and reliable in evaluating the K-slump of fresh concrete. Key words: cement paste, concrete, consistency, flow, flowability, fresh concrete, K-slump, mortar, slump, rheology, workability.

Results of reliability test program on light water reactor piping

The Japan Atomic Energy Research Institute has conducted a piping reliability test program to demonstrate the safety and reliability of light water reactor primary piping. In this program, pipe fatigue test, leak-before-break (LBB) verification test and pipe rupture test were carried out to examine the integrity of piping, to verify the LBB and to demonstrate the effectiveness of protective measures against jet impingement and pipe whip loads under a pipe rupture event. In the pipe fatigue test, a procedure to predict the fatigue crack growth was developed, and the integrity of piping during the plant service life was evaluated. In the LBB verification test, the pipe fracture test and the leak rate test were performed to verify the LBB in the primary piping. In the pipe rupture test, the influence of jet impingement on the target disk and the deformation behavior of whipping pipe and restraint were investigated. Using the test results, the jet impingement behavior and the effectiveness of pipe whip restraint were demonstrated.

軽水炉１次冷却系配管信頼性実証試験の成果概要

Upon request by the Science and Technology Agency of Japanese Government, the Japan Atomic Energy Research Institute has conducted Piping Reliability Test Program to demonstrate the safety and reliability of light water reactor primary pipings. In this report, the results of the program are summarized. In the test program, pipe fatigue tests, Leak-Before-Break (LBB) verification tests and pipe rupture tests were carried out to examine the integrity of pipings, to verify the LBB concept and to demonstrate the effectiveness of the protective measures against jet impingement and pipe whip under pipe rupture event, respectively. In the pipe fatigue tests, a procedure to predict the fatigue crack growth was developed and the integrity of piping during plant service life was demonstrated. In the LBB verification tests, pipe fracture tests and leak rate tests were performed using cracked pipes. Based on the test results, LBB in the primary pipings was demonstrated. In the pipe rupture tests, the influence of jet impingement on the target plate and the interaction between whipping pipe and restraint were investigated. Using the test results, the effect of jet impingement and the effectiveness of pipe whip restraints were demonstrated.

Diode laser degradation mechanisms: A review

Reliability engineering, unfortunately, is not widely taught in university programs, and requires a wide range of different skills and knowledge that are often difficult to piece together. Here, we share an introduction to the basics of reliability engineering as it applies to the qualification of semiconductor lasers and fiber optic transceivers, as well as other optoelectronic devices and assemblies. In this chapter, we go through the process flow for qualifying optoelectronic devices for sale, as part of the new product development process. The chapter is organized in chronological order, starting from design, development of a reliability qualification plan, setting up reliability test capabilities, data collection and analysis, qualification report contents, and finally failure analysis. While specialized books cover individual elements such as reliability calculation, burn-in optimization, or failure analysis methods, this is the first wide-ranging summary of its kind to touch on the full range of activities required in the practice of reliability engineering relevant to optoelectronics. The best-known methods for solving common challenges and building a strong reliability test program are discussed.

RT&E for the next generation weather radar (NEXRAD) system

The author describes how the military standard on reliability testing (MIL-STD-781C) has been used as a basis for planning the reliability test and evaluation program for a current electronic system development, the next generation weather radar (NEXRAD) system. A short description is given of the NEXRAD system configuration and of the availability requirements and calculations for the system. General information is provided on the system documentation relating to the reliability program. A variety of guidelines to be followed on this program that are useful for other electronic systems undergoing reliability testing is also presented. >

Ventricular assist systems for temporary life support: device readiness testing

A description is given of a quality control and reliability program for establishing short-term ventricular-assist-device (VAD) safety and efficiency prior to clinical use. Experience in the clinical use of temporary VADs indicates that the pre-clinical reliability testing program works, since no device related failures occurred. The procedures have become much stricter, and a goal of 80% reliability for in vitro testing currently exists for the permanent, ventricular-assist system with strict guidelines on how to determine device-related failure. Animal testing requires total animal-months of continued usage consistent with the 80% in vitro reliability. A critical feature of the program has been freezing of device and system design throughout the quality control/assurance program, reliability testing, and clinical use.

Type Testing of Amorphous Metal Distribution Transformers

The commercial availability of Metglas 2605S-2 amorphous metal alloy from Metglas Products Division of Allied Corporation has created the possibility of a step function reduction in no-load losses of distribution transformers. An intensive type (reliability) testing program was undertaken to verify that distribution transformers using amorphous metal cores can be built to the highest standards of quality and reliability.

Design, Fabrication and Testing of a Rock Instrumentation System for Monitoring the Thermal-Mechanical Response of Basalt

In situ testing was conducted to monitor the thermal-mechanical response of basalt subjected to heat loads simulating those expected in an actual nuclear waste repository. This paper describes the rock instrumentation system, the reliability testing program and the instrument modifications which were adopted as a result of that testing. Over 20 different performance tests were undertaken to provide calibration factors and to verify the reliability of the instruments under water-saturated conditions and temperatures as high as 200/degree/C. 9 refs.

AFSATCOM terminal segment reliability test program : Robert P. Hassett and Edward C. Jonson. Proc. IEEE Reliab. Maintainab. Symp., Philadelphia (Jan. 18–20, 1977) p. 372

AFSATCOM terminal segment reliability test program : Robert P. Hassett and Edward C. Jonson. Proc. IEEE Reliab. Maintainab. Symp., Philadelphia (Jan. 18–20, 1977) p. 372

Silicon P-N Junction Radiation Detectors for the Telstar® Satellite

This paper describes the development and testing of the silicon p-n junction nuclear particle detectors which have been ued in the radiation experiments of the TELSTAR® communication satellite, and the Relay and Explorer XV satellites. The sensitive element of the detector is a diffused mesa diode of 10,000 to 20,000 ohm-cm p-type silicon. It is encapsulated in a transistor-type can with a thin (0.3 mil) Kovar window. In spite of the encapsulation, surface reliability was a major development problem. An extensive reliability testing program revealed several types of surface instability. Nevertheless, a high degree of reliability was achieved in most of the detectors, including those which were used on satellites.

Standard Hardware and Corrosion: Pershing Problems and Action

During the Pershing reliability testing program, corrosion was encountered on standard mounting hardware. Investigation revealed an extremely low level of compliance of incoming hardware to the plating thickness requirements of military and Martin specifications. Most proposed solutions would have required extensive documentation changes or additional facilities. None of the approaches directly affected the actual cause of the problem: standard mounting hardware vendors supplying material which does not meet purchase requirements. The following approach to the problem has therefore been initiated. 1. A general purchase description for sampling, inspection and test procedures for all standard mounting hardware has been prepared. 2. Samples of hardware from a cross-section of vendors have been ordered under this purchase description. 3. Hardware received under this program will be inspected for compliance with the drawing requirements and the special purchase description. Availability of hardware and cost increases will be analyzed.

Safety Margins Established by Combined Environmental Tests Increase Atlas Missile Component Reliability

A reliability test program known as a ``Search for Critical Weaknesses'' has been put into operation by the Convair-Astronautics Reliability Organization. The function of this program is to detect critical component weaknesses so that corrective action can be taken before operational failure occurs. Components selected for testing are subjected to combined environmental severlties at and beyond the design requirements. This is done in order to establish a margin of safety and to be able to reassess component reliability in the event that actual flight environments differ from those expected. After completing the first three phases of this program, 203 component types, consisting of 980 individual specimens have been evaluated. A fourth phase in which 105 component types are being tested is nearing completion and a fifth phase has been initiated. This paper covers the testing procedures and the techniques used in determining the relative component reliability during the first three phases of the testing program. In addition, an explanation of representative components' weaknesses was revealed during the tests, and the corrective action taken has been included.

Data Handling for a Reliability Test Program

Data Handling for a Reliability Test Program