Weibull metallic

Weibull - Fatigue enduranee strength of metals and strength of eeramie materials. 

Coppard et al (1989) measured the breakdown field of polyethylene plaques loaded with metallic particles in very small quantities. Their results concern the range of low p. One of the purposes of this study was to determine the distribution probability F E y) to distinguish between the Gumbel and the Weibull distributions. But it appears to be very difficult a task experimentally, because a large number of samples are needed for the study. However, they were able to verify that the average of the breakdown fields varies with p in accordance with (2.68). 

The Weibull modulus of an alumina bioceramic is given as 8.4. (a) What does a value of m = 8.4 imply (b) For an implant made out of a metal the value of m 100. What implications would this have for lifetime predictions for the metal component compared to the alumina component (c) How does the value of m affect... 

Soni PR, Rajan TV, Ramakrishnan P, Continuous nickel electroplating of carbon fibers and Weibull analysis of their tensUe strengths. Metals Mater Proc, 8(2), 187-191, 1996. 

Nascimento DCO, MottaLC, Monteiro SN (2010) Weibull analysis of tensile tested piassava fibers with different diameters. In Proceedings of characterization of minerals, metals and materials - TMS 2010, Seattle, USA, 21-25 Feb 2010, pp 1-8... 

In the above relations, is the stress level below which the probability of failure is zero, in other words, the probability of survival is 1.0. The Weibull modulus, m, principally has values in the range O-oo. In metals, the value of m is 100 and for ceramics m < 3, but this value depends on the soundness of the ceramics. Well-controlled engineering ceramics with fewer flaws may even have an m value in the range of 5-10. 

The Weibull distribution is useful for studies involving brittle fracture and fatigue of metals. It is widely used in the testing and analysis of ball and roller bearings. In the application of Weibull statistics, specially... 

Suppose the time to failure of a metal wire can be modeled by the Weibull distribution with b = 1/5 and a = 300 h. To find the mean time to failure using the expected value of a Weibull random variable ... 

In order to verify the volume effect it has been used a metal with a very low Weibull exponent like ferritic ductile cast iron (DCI). To that purpose, live sets of 15 specimens each have been prepared. Each set has the same volume that varies from set to set from a minimum of 500 mm to a maximum of 400,000 mm. Each set of specimens has been subjected to a monotonic traction test and the yield strength analysed with the Weibull approach to infer the relative m exponent and the scale factor ag. Results are shown in Fig. 4.28 and listed in the following table. 

Weibull, W. Theory of fatigue crack propagation in sheet specimens. Acta Metall. 11(2), 725 (1963)... 

FIG. 33 Weibull plot for a 208 I/O CSP accelerated thermal cycle tested in the temperature range from -40°C to 125°C. (Courtesy of Chip Pac, Alpha Metals, Sanmina, Hewlett Packard, Ref. 96.)... 

---