This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: EMA 4714 - Materials Selection and Failure Analysis Unit 1 Examination Wednesday , February 13, 2008 Name _______________________ Open Book/Open Notes 1. [10 points] Considering the inherent asymmetry of W-shape beams as used in the boat-lift case study, you are being asked to redesign using HSS [Hollow Structural Section] shapes, which would eliminate the problem which was manifest in the lift failure. Your design should be equivalent to the Davit Master 7M model in terms of the weight bearing capacity [70% of 7000 pounds on rear support] and beam length [12 feet], but increase the safety margin by assuming WCS [worst case scenario] - all weight on rear support - and a load safety factor of 1.25. In addition, you are instructed to consider weight [no more than 150 pounds for a 12 foot long beam] and cost. You may design for two point loading on supports which are 3 feet apart [1.5 feet on each side of center]. Vendors for A572, grade 50 low alloy structural steel [f = 50 ksi] and 17ST aluminum structural alloy [equivalent to wrought 2017 T4, f = 35 ksi] are available. Based on data in the table below for 4.5-inch HSS square sections of varying wall thickness, design a support on data in the table below for 4....
View Full Document
This note was uploaded on 07/24/2011 for the course EMA 4714 taught by Professor Staff during the Spring '08 term at University of Florida.
- Spring '08