McConnell (1999) presented a structural composites application in an Arctic Cat snowmobile, an eight-piece front suspension assembly designed and manufactured by Creative Composites of Manistique, MI. In the US, the main manufacturers of snowmobiles are Arctic Cat, Polaris, Ski-Doo (Bombardier), and Yamaha. Further, the increase in sales of snowmobiles averaged 14% per year from 1993 to 1996. Loud (1999b) reported these key facts from the International Snowmobile Manufacturers Association: in North America 2.3 million snowmobiles are registered, nearly 163 000 are sold each year, and the average amount spent annually on snowmobiling in the US is $6 billion. Stronger slugger: hitting out of the ballpark with less breaking, chipping, and cracking is possible with the Baum Bat that uses S-2 glass fibers (as well as carbon and aramid) for reinforcement (source: Owens Corning). The mechanical properties achieved in MicrotuffR are comparable to those attained by the conventional reheated, quenched, and tempered low alloy AISI 4140 steel. The MicrotuffR compositions and mechanical properties are given in Table 13.3. The fine-grained auto-tempered martensitic forging exhibits high yield strength (945–1225 MPa) coupled with an impact transition temperature well below zero. Direct quenching produces a martensitic microstructure which is allowed to auto-temper. The grain size remains fine with better than ASTM 5 at forging temperatures up to 1290☌. A fine dispersion of undissolved Nb (C, N) particles retards the recrystallization and prevents austenite grain growth during forging, trimming, and during any entry delay into the quenchant that might be experienced. This was designated as MicrotuffR (a trade mark of the Chaparral Steel Company). Nine lower control arms were tested to failure on a jounce to rebound test fixture. It is extremely useful in detecting outliers, in estimating the minimum life (location parameter), and in helping with the decision as to whether observed failure times are from a Weibull distribution.
![lower control arm lower control arm](https://pure4runner.com/images/86555-E-10FJc.jpeg)
The MLE method is recommended because the maximum likelihood estimates often have desirable statistical properties.Ī graphical plot provides a representation of the data that is easily understood by the engineer. The MLE method is a statistical procedure for parameter estimation by maximizing the likelihood function ( Mann et al., 1974). The rank regression method is a graphical plotting technique by using linear regression along with median rank plotting ( Kapur and Lamberson, 1977).
#Lower control arm software#
Two basic parameter estimation methods (rank regression method and maximum likelihood estimator, MLE, method) are used in most commercially available software packages.