Fatigue: Cracks caused by metal fatigue

In MEMSS: Data Sets from Mixed-Effects Models in S

Description

The Fatigue data frame has 262 rows and 3 columns.

Format

This data frame contains the following columns:

Path

the test path (or test unit) identifier - a factor with levels A to U.

cycles

number of test cycles at which the measurement is made (millions of cycles).

relLength

relative crack length (dimensionless).

Details

These data are given in Lu and Meeker (1993) where they state “We obtained the data in Table 1 visually from figure 4.5.2 on page 242 of Bogdanoff and Kozin (1985).” The data represent the growth of cracks in metal for 21 test units. An initial notch of length 0.90 inches was made on each unit which then was subjected to several thousand test cycles. After every 10,000 test cycles the crack length was measured. Testing was stopped if the crack length exceeded 1.60 inches, defined as a failure, or at 120,000 cycles.

Source

Lu, C. Joseph , and Meeker, William Q. (1993), Using degradation measures to estimate a time-to-failure distribution, Technometrics, 35, 161-174

Examples

require(lattice)
str(Fatigue)
xyplot(relLength ~ cycles | Path, Fatigue, type = c("g", "b"),
       aspect = 'xy', xlab = "Number of test cycles (millions)",
       ylab = "Relative crack length (dimensionless)",
       layout = c(7,3))

Example output

Loading required package: lme4
Loading required package: Matrix

Attaching package: 'MEMSS'

The following objects are masked from 'package:datasets':

    CO2, Orange, Theoph

Loading required package: lattice
'data.frame':	262 obs. of  3 variables:
 $ Path     : Factor w/ 21 levels "1","10","11",..: 1 1 1 1 1 1 1 1 1 1 ...
 $ cycles   : num  0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 ...
 $ relLength: num  1 1.06 1.11 1.17 1.24 ...

MEMSS documentation built on May 2, 2019, 1:05 p.m.