Fatigue failure analysis of a leg press exercise machine

✍ Scribed by P.J. Vernon; T.J. Mackin

• Book ID: 104383589
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 762 KB
• Volume: 6
• Category: Article
• ISSN: 1350-6307
• DOI: 10.1016/s1350-6307(98)00030-2

✦ Synopsis

The following paper is an engineering failure analysis of an adjustment pin used in a leg press exercise machine[ The pin is used to allow adjustment of the machine for people of di}erent heights[ It was modeled as a cantilever beam subjected to varying forces depending on the weight stack setting[ The fracture occurred at a point of localized stress concentration[ The analysis shows an elastic stress concentration of 0[56 which would cause plastic deformation and a fatigue stress concentration of 0[27 that led to the eventual fatigue failure[ Based on actual user data\ a block loading analysis was used to calculate a pin lifetime of approxi! mately one year[ The pin actually failed after 0 0 1 years of use[ Design changes are recommended to reduce the size of the stress concentration and subsequently increase the life of the adjustment pin[