Fadigue reliability analusis : case study automotive suspension control arm / Analise de confiabilidade em fadiga : estudo de caso : braço de controle de suspensão automotiva

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

This dissertation aims at describing a procedure for approval of a suspension control arm subjected to high-cycle fatigue and, simultaneously, at proposing a validation alternative method based on reliability concepts and statistical theories. In that manner, the research provides not only an assessment of the procedure followed by the manufacturer, but also analytical and graphical comparisons of probabilistic distributions (normal, lognormal, Weibull) in order to characterize the set of complete and suspended data from bench accelerated tests. A sample space comprised by four complete final configuration observations and eight complete primary configuration ones, in addition to twelve suspended figures, was the basis for determining the model parameters. Such an analysis led to choose the bi-parametric Weibull for both focused configurations time to failure. The ultimate estimation of the parameters was performed through the maximum likelihood method, which beat a specific alternative method for Weibull when compared with the referential category distribution. Thus, the effective gain in reliability resulting from the product development additional effort was calculated. The Kruskal-Wallis hypothesis testing guided the conclusion that the two configurations actually have different durability performances. It is impressive the gain in reliability brought by the changes that led towards the final configuration: taking an amount of one million parts into consideration, the expected number of failures at 30,000 cycles dropped from 96,384 to 5 parts per million

ASSUNTO(S)

durabilidade (engenharia) automobiles steel aço - fadiga weibull confiabilidade (engenharia) automoveis - molas e suspensão reliability distribution (probability theory) durability distribuição (probabilidades)

ACESSO AO ARTIGO

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