Deterioration Identification of Structural Concrete Ground on Residual Bearing Capacities

2014 ◽  
Vol 501-504 ◽  
pp. 1963-1967
Author(s):  
Hua Shu Yang ◽  
Ying Ju Pu ◽  
Yu Lu Yang ◽  
Xin Long Peng ◽  
Yi Wang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Accelerated Life Test ◽  
Life Test ◽  
Structural Concrete ◽  
Concrete Buildings ◽  
Accelerated Life ◽  
Key Points ◽  
Building Deterioration ◽  
The Relationship

Found on data of accelerated life test, the relationship between outward disease of structural concrete and holistic deterioration of building was analysed. The results indicated that: outward diseases of structural concrete, such as abrasion, scour erosion, and peeling, carbonization etc, are not hypostatic breakage for holistic building, so could not be regarded as the key points of deterioration identification at building. Deterioration appraisement should be focused on detections of engineering indices relating to structural inbeing quality and analyses of multifarious remainder relating to bearing capacity. Only in this way, deterioration degree of structural concrete and efficacious repair indices could be factually incarnated. Ground on testing multifarious bearing capacities, deterioration identification of concrete buildings was founded, and remedy principles corresponding to inbeing deterioration indices were put forward.

Mechanical and Electrical Products Reliability Estimation under Weibull Distribution Based on Accelerated Life Test

2013 ◽  
Vol 302 ◽  
pp. 332-337
Author(s):  
Bo Wan ◽  
Gui Cui Fu ◽  
Li Wang
Keyword(s):  
Weibull Distribution ◽  
Normal Stress ◽  
Shape Parameter ◽  
Interval Estimation ◽  
Reliability Estimation ◽  
Accelerated Life Test ◽  
Point Estimate ◽  
Life Test ◽  
Accelerated Life ◽  
The Relationship

In practice, most mechanical and electrical products life obeys Weibull distribution.This paper based on the relationship between Weibull distribution and exponential distribution, improved the point estimate of characteristic life during the normal stress and enhanced the precision of analysis. The point estimate of the shape parameter under normal stress level was presented, when the assumption that the shape parameter under different stress levels keeps invariable was got rid of. Meanwhile, a means was put forward to give interval estimation of the Weibull distribution parameter and the lower confidence limit of the reliability. Finally, an example of the mechanical and electrical product’s constant-stress accelerated life test was given and proved that the proposed approach is accuracy. It should be valuable for implement of engineering.

Study of High-Power White LED's Lifetime Based on Accelerated Life Test

2013 ◽  
Vol 800 ◽  
pp. 205-209 ◽  
Author(s):  
De Sheng Li ◽  
Nian Yu Zou ◽  
Yun Cui Zhang ◽  
Xiao Yang He ◽  
Yi Yang
Keyword(s):  
High Power ◽  
Accelerated Life Test ◽  
Reliability Test ◽  
White Led ◽  
Life Test ◽  
Arrhenius Model ◽  
White Leds ◽  
Accelerated Life ◽  
Temperature Levels

The study of LED reliability becomes more and more important with LED widely used in various areas, and accelerated life test (ALT) as an element of reliability test is widely used to predict the lifetime of LED. In this paper, ALTs have been carried out at various current levels and various temperature levels. In the current ALT experiment, three kinds of stressing currents were demonstrated for 1W white LEDs and lumen flux of the tested LEDs were studied, and based on Eyting model, lifetime of the tested LEDs is calculated about 6.86×105h. In the temperature ALT experiment, two kinds of stressing temperature were demonstrated for the same type of white LEDs and lumen flux were also studied, and based on Arrhenius model, lifetime of the tested LEDs is calculated about 7.41×105h. In addition, the color shifting velocity is faster than lumens depreciation velocity was observed in our experiment, which means the lifetime evaluating of white LED should be paid more attention.

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