Accession Number:

AD0432338

Title:

EARLY FAILURES IN AUTOMOBILE PARTS: A BACKGROUND STUDY IN RELIABILITY,

Descriptive Note:

Corporate Author:

RAND CORP SANTA MONICA CALIF

Personal Author(s):

Report Date:

1964-03-01

Pagination or Media Count:

34.0

Abstract:

The early mortality of automobile parts is examined here through the analysis of warranty-claim information from one American manufacturer of passenger cars for the model year 1961. The Weibull probability distribution is fitted to the early claims data to indicate the trend -- increasing, or constant -- in the observed failure rate. Since the data come from a non-random sample, a simulation of the claim-generating process is performed to develop the exposure pattern and permit the actuarial determination of the true conditional failure rates for the analysis. The results show that a substantial majority of the 36 parts analyzed display a very distinct decrease in the observed failure rate during the first few thousand miles of operation. Two parts which were studied categorically elsewhere show the constant failure rate found by previous studies, and one part with an increasing failure rate is shown to operate in a progressively increasing stress-regime. We conclude that the economic limitations on quality-control efforts in this industry result in a higher proportion of initial but hidden defects by comparison with the aircraft parts studied previously. We also conclude that quality control and running-in are at least partial substitutes for one another. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE