Reliability growth testing, what is the real final result? Accelerated test methodology for reliability growth

2014 ◽  
Author(s):  
Milena Krasich
Keyword(s):  
Reliability Growth ◽  
Accelerated Test ◽  
The Real ◽  
Test Methodology

A Processing Method for Combined Fatigue Accelerated Test Data

2017 ◽  
Author(s):  
Songwang Zheng ◽  
Cao Chen ◽  
Lei Han ◽  
Xiaoyong Zhang ◽  
Xiaojun Yan
Keyword(s):  
Data Processing ◽  
Test Data ◽  
Turbine Blades ◽  
Processing Method ◽  
Test Time ◽  
Accelerated Test ◽  
The Real ◽  
Data Processing Method ◽  
Stress Levels ◽  
Vibration Stress

To carry out combined low and high cycle fatigue (CCF) test on turbine blades in a bench environment, it is imperative to simulate the vibration loads of turbine blades in the field. Due to the low vibration stress of turbine blades in the working state, the test time will be very long if the test vibration stress is equal to the real vibration stress in working state. Therefore, an accelerated test will be used when the test life reach the target value (typically 107). During the accelerated test, each blade is tested at two or more times than the real vibration stress. That means some specimens are tested under two vibration stress levels. In this case, a reasonable data processing method becomes very important. For this reason, a data processing method for the CCF accelerated test is proposed in this paper. These test data are iterated on the basis of S-N curve. Finally, ten real turbine blades are tested in a bench environment, one of them is tested under two vibration stress levels. The test data is processed using the method proposed above to obtain the unaccelerated life data.

Mechanical and Accelerated Testing of Flip Chip Interconnect Systems

1993 ◽  
Vol 323 ◽  
Author(s):  
Ravi Subrahmanyan
Keyword(s):  
Flip Chip ◽  
Test Methods ◽  
Temperature Cycling ◽  
Accelerated Test ◽  
Solder Interconnects ◽  
Test Methodology ◽  
Low Profile ◽  
Interconnect Systems ◽  
Interconnect System

AbstractFlip chip interconnect systems are becoming increasingly popular in the electronics industry due to their low profile and high densities. During temperature cycles, the differential expansions between various assembly members of a flip chip interconnect system produce mechanical stresses that are the driving force for failures. Such failures can be a significant reliability concern.Accelerated test methodologies for flip chip interconnect systems assess the reliability of existing interconnects and identify potential reliability concerns in future interconnect designs. Traditionally, such methodologies have relied on test methods such as temperature cycling to determine the mechanical integrity of the flip chip interconnect. However, application of such methods to new interconnect materials, geometry and processes requires characterization of basicmechanical behavior of the interconnect system.In this work, the feasibility of using a micromechanical test methodology for flip chip applications is examined. 90PbSn solders is used as an example. The data obtained from such flip chip solder interconnects is validated using a damage integral methodology. The measured data is shown to adequately describe published thermal stress profiles and thermal fatigue life data measured using solder joints of the same composition. Finally, some considerations in the application of micromechanical measurements to determination of acceleration factors and development of accelerated test methods are discussed.

Environmental Aging and Deadhesion of Polyimide Dielectric Films

2004 ◽  
Vol 126 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Steven Murray ◽  
Craig Hillman ◽  
Michael Pecht
Keyword(s):  
Failure Mechanism ◽  
Tensile Tests ◽  
Dielectric Films ◽  
Accelerated Test ◽  
Damage Mechanisms ◽  
Electronic Products ◽  
Test Methodology ◽  
Temperature And Humidity ◽  
Environmental Aging

One possible failure mechanism of products containing polyimide dielectric is deadhesion of polyimide from neighboring metallization. Deadhesion usually occurs due to the combined damage mechanisms of environmental aging and fatigue. In this paper, the rate of aging of Kapton-E polyimide is quantified as a function of temperature and humidity exposure using peel and tensile tests. An accelerated test methodology that accounts for both aging and fatigue and that can be used to evaluate the resistance of electronic products to polyimide deadhesion is then proposed.

scholarly journals Analysis of Long-Term Change in the Thermal Resistance of Extruded Insulation Materials Through Accelerated Tests

2021 ◽  
Vol 11 (19) ◽  
pp. 9354
Author(s):  
Hyun-Jung Choi ◽  
Hosang Ahn ◽  
Gyeong-Seok Choi ◽  
Jae-Sik Kang ◽  
Jung-Ho Huh
Keyword(s):  
Thermal Resistance ◽  
Real Time ◽  
Thermal Performance ◽  
Test Method ◽  
Ageing Process ◽  
Accelerated Test ◽  
The Real ◽  
Insulation Materials ◽  
Term Change

Two experiments were executed to examine the slice accelerated test method, suggested in ISO 11561 “Ageing of thermal insulation materials—Determination of the long-term change in thermal resistance of closed-cell plastics (accelerated laboratory test methods)” and to observe the changes in the thermal performance of insulation material over time by the real-time ageing process. The accelerated test method was conducted for 120 consecutive days using 10 mm thick-sliced specimens, which were sampled from a 50 mm thick plate body. The real-time ageing process was performed for 5000 consecutive days under constant temperature and relative humidity conditions as of 20 ± 5 °C and 50 ± 5% without any slicing. Degradation of thermal performance was shown to be stabilized at around 38 to 41% down from the initial values, which were correspondent with the approximately 10 days after the initial time. The real-time ageing process revealed similar degradation levels at around 130 days after the starting point. Converting the results using the scaling method specified in ISO 11561, the change was found in the range of 37 to 41% for the thermal resistance after 25 years and of 30 to 38% for the 25-year-average thermal resistance, respectively. Within the 10% error range, both the accelerated method and real-time ageing resulted in a similar level of degradation. Consequently, it was our observation that the slice accelerated test was quite enough to predict the practical degradation of insulation materials with at least 90% of accuracy under the specified time duration, temperature and thickness satisfactions.

STOCHASTIC SOFTWARE PERFORMABILITY EVALUATION BASED ON NHPP RELIABILITY GROWTH MODEL

2011 ◽  
Vol 18 (05) ◽  
pp. 431-444 ◽  
Author(s):  
KOICHI TOKUNO ◽  
TATSUYA NAGATA ◽  
SHIGERU YAMADA
Keyword(s):  
Real Time ◽  
Software Reliability ◽  
Time Limit ◽  
Arrival Process ◽  
Reliability Growth ◽  
Queuing Model ◽  
The Real ◽  
Time Property ◽  
Software Reliability Growth ◽  
Dynamic Software

In this paper, we discuss the software performability evaluation considering the real-time property; this is defined as the attribute that the system can complete the task within the stipulated response time limit. The dynamic software reliability growth process is described by the nonhomogeneous Poisson process (NHPP). Assuming that the software system can process multiple tasks simultaneously and that the arrival process of the tasks also follows an NHPP, we analyze the distribution of the number of tasks whose processes can be completed within the processing time limit with the infinite-server queuing model. We derive several software performability measures considering the real-time property. Finally, we illustrate several numerical examples of the measures and discuss the software performability analysis.

Lifetime estimation of glass reinforced epoxy pipes in acidic and alkaline environment using accelerated test methodology

2014 ◽  
Vol 15 (9) ◽  
pp. 1935-1940 ◽  
Author(s):  
Pramod Marru ◽  
Vaibhav Latane ◽  
C. Puja ◽  
K. Vikas ◽  
Pushpendra Kumar ◽  
...  
Keyword(s):  
Lifetime Estimation ◽  
Accelerated Test ◽  
Alkaline Environment ◽  
Test Methodology

Scanning electron microscopy of human iliac bone by a simple preparation method

1990 ◽  
Vol 48 (3) ◽  
pp. 226-227
Author(s):  
Toshihiko Takita ◽  
Tomonori Naguro ◽  
Toshio Kameie ◽  
Akihiro Iino ◽  
Kichizo Yamamoto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Real Surface ◽  
Public Attention ◽  
Preparation Methods ◽  
The Real ◽  
Simple Preparation ◽  
Scanning Electron

Recently with the increase in advanced age population, the osteoporosis becomes the object of public attention in the field of orthopedics. The surface topography of the bone by scanning electron microscopy (SEM) is one of the most useful means to study the bone metabolism, that is considered to make clear the mechanism of the osteoporosis. Until today many specimen preparation methods for SEM have been reported. They are roughly classified into two; the anorganic preparation and the simple preparation. The former is suitable for observing mineralization, but has the demerit that the real surface of the bone can not be observed and, moreover, the samples prepared by this method are extremely fragile especially in the case of osteoporosis. On the other hand, the latter has the merit that the real information of the bone surface can be obtained, though it is difficult to recognize the functional situation of the bone.

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