Study on Reliability Growth Test Method for Disc Magazine and Manipulator

2014 ◽  
Vol 904 ◽  
pp. 335-339
Author(s):  
Jing Ying Duan ◽  
Chang Jing Fu
Keyword(s):  
Test Data ◽  
Weibull Model ◽  
Small Sample ◽  
Accelerated Life Testing ◽  
Test Method ◽  
Distribution Model ◽  
Accelerated Life ◽  
Acceleration Model ◽  
Selection Of

The life distribution model and accelerated life testing methods of the disc magazine and manipulator were discussed. The small sample determination of truncation test was performed to QY011 and a batch of test data under the accelerated stress at the selection of vibration as the accelerated stress have been obtained. The reliability life index under certain stress level was analyzed through established the accelerated probability weighted Weibull model and inversed power law model for acceleration model. According to the acceleration model and statistical analysis of test data, the QY011 reliability life level of QY011 disc magazine and manipulator under the normal working conditions were calculated.

Study on Electrical Aging Lifetime of Power Cable with Extruded Insulation

2010 ◽  
Vol 156-157 ◽  
pp. 1041-1045
Author(s):  
Wei Guo Li ◽  
Gao Sheng Ye ◽  
Shi Kun Wang
Keyword(s):  
Test Data ◽  
Stress Test ◽  
Least Square Method ◽  
Weibull Model ◽  
Least Square ◽  
Test Method ◽  
Power Cable ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Electrical Aging

Extruded insulation is a major kind of insulation used in power cable. It is significant to evaluate extruded insulation lifetime suffered from electrical aging, which can improve the reliability of power cable. In this paper, a step-stress test method is used in accelerated life tests and Weibull model is used to statistic analysis for the mean lifetime of several samples under the same voltage value, and then the least square method is used to calculate the parameter of Weibull distribution. This paper uses inverse power function to fit test data and calculate voltage endurance coefficients. Constant-stress test data is also used as the counterpart of that measured by the step-stress test. It is indicated that the test voltages of step-stress test are more easily selected than that of constant tests and the data of the former is less scattered and the result is more reliable.

POWER-LAW ACCELERATED BIRNBAUM–SAUNDERS LIFE MODELS

2000 ◽  
Vol 07 (01) ◽  
pp. 1-15
Author(s):  
W. J. OWEN ◽  
W. J. PADGETT
Keyword(s):  
Power Law ◽  
Testing Procedure ◽  
Accelerated Life Testing ◽  
Data Set ◽  
Inverse Power Law ◽  
Accelerated Life ◽  
Acceleration Model ◽  
Life Model ◽  
Accelerated Life Model ◽  
Selection Of

An accelerated life testing procedure can reduce the lifetime of a material by observing the material's behavior under higher levels of stress than what is normally encountered. Useful inference hinges on the selection of an appropriate lifetime distribution and the substitution of an acceleration model for a distribution parameter, such as the mean or scale. The (inverse) power-law model is one such acceleration model that has applications to fatigue studies in metals, where failure tends to be crack-induced. The Birnbaum–Saunders distribution was developed to model fatigue in materials where the failure of a specimen is due to the propagation of a dominant crack. This paper will compare two Birnbaum–Saunders type models from the literature (that have power-law accelerated features) with a new but distinctive model proposed here. The new model is an accelerated life model for a reparameterization of the baseline distribution. Comparison of the three models will be via the aluminum coupon data set from Birnbaum and Saunders5 and issues of accelerated testing will be discussed.

A Study on Procedures of the Accelerated Life Testing for Hose Assemblies

2005 ◽  
Vol 297-300 ◽  
pp. 1870-1875
Author(s):  
Y.B. Lee ◽  
Hyoung Eui Kim ◽  
J.H. Park ◽  
J.M. Ko
Keyword(s):  
Accelerated Life Testing ◽  
Test Method ◽  
Life Testing ◽  
Life Test ◽  
Life Distribution ◽  
Burst Test ◽  
Manufacture Process ◽  
Accelerated Life ◽  
Long Time ◽  
Impulse Pressure

There are several types of life test method for hose assemblies. The two major tests used for hose assemblies are impulse test and burst test. And magnification adjustment of impulse pressure, heating of testing oil and repetitive motions of bending and straightening of testing hose are also performed for accelerating the life. According to the manufacture process of hose and swaging process of fitting, there is a difference in the life of hose assemblies from minimum 7 times to maximum 40 times during the life test in the same functioning condition. Like this, the life test of hose which has a wide scope of life distribution gives a problem that observation should take a long time to find out the existence of the bursting from the beginning of the test to the completion of bursting of hose assemblies. Therefore, this research proposes a process of concentrating on the defective section of hose assemblies and maximizing the life acceleration by giving ‘Knockdown stress’ to hose assemblies just until before the hose assemblies get out of order.

Computational mechanical property determination of viscoelastic/plastic materials from nanoindentation creep test data

2009 ◽  
Vol 24 (3) ◽  
pp. 1245-1257 ◽  
Author(s):  
Jianjun Wang ◽  
Timothy C. Ovaert
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Test Data ◽  
Plastic Material ◽  
Test Method ◽  
Element Formulation ◽  
Unknown Parameters ◽  
Plastic Materials

Nanoindentation is a widely accepted test method for materials characterization. On account of the complexity of contact deformation behavior, design of parametric constitutive models and determination of the unknown parameters is challenging. To address the need for identification of mechanical properties of viscoelastic/plastic materials from nanoindentation data, a combined numerical finite element/optimization-based indentation modeling tool was developed, fully self-contained, and capable of running on a PC as a stand-alone executable program. The approach uses inverse engineering and formulates the material characterization task as an optimization problem. The model development consists of finite element formulation, viscoelastic/plastic material models, heuristic estimation to obtain initial solution boundaries, and a gradient-based optimization algorithm for fast convergence to extract mechanical properties from the test data. A four-parameter viscoelastic/plastic model is presented, then a simplified three-parameter model with more rapid convergence. The end result is a versatile tool for indentation simulation and mechanical property analysis.

A Fundamental Overview of Accelerated Testing Analytical Models

1998 ◽  
Vol 41 (1) ◽  
pp. 16-20 ◽  
Author(s):  
Hank Caruso ◽  
Abhijit Dasgupta
Keyword(s):  
Fatigue Damage ◽  
Accelerated Life Testing ◽  
Analytical Models ◽  
Aging Effects ◽  
Chemical Aging ◽  
Life Estimation ◽  
Mechanical Fatigue ◽  
Accelerated Life ◽  
Steady State Temperature ◽  
Acceleration Model

This paper describes analytical models that are commonly used for product life estimation and accelerated life testing. Model descriptions include: Miner's "Rule" for describing accumulated fatigue damage; Coffin-Manson nonlinear power law, often applied to mechanical fatigue damage; Rudra model for CFF failures; Arrhenius steady-state temperature acceleration model for estimating chemical aging effects; Peck's model for accelerated combined temperature-humidity effects; and Kemeny model for combined temperature and voltage acceleration effects. The general form of these models will be presented along with specific guidance regarding: relative strengths and appropriate applications for each model; limitations and sources of uncertainty for each model; and example values for exponents and material coefficients.

Development of Accelerated Life Test Method of Hydraulic Pump

2006 ◽  
Vol 326-328 ◽  
pp. 1861-1864
Author(s):  
Dong Soo Jung ◽  
Hyoung Eui Kim ◽  
Sung Hun Kim ◽  
E Sok Kang
Keyword(s):  
Duty Cycle ◽  
Weighted Average ◽  
Life Time ◽  
Test Method ◽  
Accelerated Life Test ◽  
Hydraulic Pump ◽  
Life Test ◽  
Accelerated Life ◽  
Equivalent Load

This paper proposes a new accelerated life test method of hydraulic pump used in vehicles, which have multiple alternating loads. For determination of life time of hydraulic pump for given field conditions with respect to duty cycle, the equivalent load and speed of this unit has to be determined. Equivalent load and speed can be calculated from the given duty cycle using the predominant theory for cumulative fatigue damage. Finally, we can perform accelerated life test on hydraulic pump by determination of test pressure and speed from calculated equivalent cumulative damage per working cycle and weighted average speed.

Fan Performance Testing Using Inlet Measuring Methods

1973 ◽  
Vol 187 (1) ◽  
pp. 405-412
Author(s):  
J. Whitaker
Keyword(s):  
Flow Measurement ◽  
Performance Testing ◽  
Test Methods ◽  
Test Method ◽  
Fan Performance ◽  
Optimum Configuration ◽  
Free Discharge ◽  
Pressure Selection ◽  
Selection Of

To contend with installation variants the fan must be tested in a system that resembles its site installation. Four simplified system arrangements are covered with two inlet test methods—ducted inlet and free inlet—by adding ducts to the free discharge. With free inlet tests a plenum chamber is attached to the fan inlet in order to obtain the required measurements; investigations to provide information concerning the optimum configuration of this test method are described. Determination of static pressure, selection of inlet devices for flow measurement; simulation of inlet and outlet ducts and the method of loading are also discussed.

Fan Performance Testing Using Inlet Measuring Methods

1973 ◽  
Vol 187 (1) ◽  
pp. 405-412
Author(s):  
J. Whitaker
Keyword(s):  
Flow Measurement ◽  
Performance Testing ◽  
Test Methods ◽  
Test Method ◽  
Fan Performance ◽  
Optimum Configuration ◽  
Free Discharge ◽  
Pressure Selection ◽  
Selection Of

To contend with installation variants the fan must be tested in a system that resembles its site installation. Four simplified system arrangements are covered with two inlet test methods—ducted inlet and free inlet—by adding ducts to the free discharge. With free inlet tests a plenum chamber is attached to the fan inlet in order to obtain the required measurements; investigations to provide information concerning the optimum configuration of this test method are described. Determination of static pressure, selection of inlet devices for flow measurement; simulation of inlet and outlet ducts and the method of loading are also discussed.

scholarly journals ACCELERATED LIFE TESTING WITH AN UNDERLYING THREE-PARAMETER WEIBULL MODEL

Engevista ◽  
2010 ◽  
Vol 7 (1) ◽  
Author(s):  
Daniel I. de Souza Jr. ◽  
Kamalesh Somani
Keyword(s):  
High Stress ◽  
Linear Acceleration ◽  
Weibull Model ◽  
Test Sample ◽  
Accelerated Life Testing ◽  
Life Testing ◽  
Distribution Models ◽  
Testing Model ◽  
Failure Data ◽  
Accelerated Life

The main objective of life testing is to obtain information concerning failure. This information should then be used in order to quantify reliability, improve product reliability, and to determine whether safety and reliability goals are being met. The amount of time available for testing directly at use conditions, that is, with practical test times and realistic (relatively) small test sample sizes, could be considerably less than the component’s expected lifetime. To overcome such a problem, there is the life-testing alternative aimed at forcing components to fail by testing them at much higher than the intended application conditions. By doing this, we will get failure data that can be fitted to life distribution models. To go from the failure rate obtained at high stress to what a product or service is likely to experience at much lower stress, under use conditions, we will need additional modeling. These models are known as acceleration models. The accelerated life testing concept is such that a component, operating under predetermined (correct) levels of increased stress, will have exactly the same failure mechanism as observed when used at normal stress levels. For example, if the time of testing is measured in cycles, then the time squeezing may only require increasing the number of cycles per unit of time. In this study, we will develop an accelerated life-testing model in which the underlying sampling distribution is the three-parameter Weibull model. We will be assuming a linear acceleration condition. An example will illustrate the application of the proposed accelerated life-testing model.  

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