This preview shows pages 1–4. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: MechEng 382 Winter 2009 Homework #8 Solutions 1. [ Dowling , Prob. 8.5] Define the following concepts in your own words: (a) Modes I, II, and III, (b) cracktip singularity, (c) stress intensity factor, (d) strain energy release rate G , and (e) fracture toughness K Ic 1 MechEng 382 Winter 2009 Homework #8 Solutions 2. [ Dowling , Prob. 8.6] A centercracked plate of AISI 1144 steel has dimensions, as defined in Fig. 8.12(a), of b = 40mm and t = 15mm . For a safety factor of three against brittle fracture, what is the maximum permissible force P on the plate if the crack halflength a is (a) 10mm, and Solution P = 1 . 49 10 5 N = 149kN . (1) (b) 24mm? Solution P = 7 . 44 10 4 N = 74 . 4kN . ( 1 ) 2 MechEng 382 Winter 2009 Homework #8 Solutions 3. [ Dowling , Prob. 8.8] A tension member is made of AISI 1045 steel (Fig. 8.7) heat treated to a hardness of HB = 400 . It has a width of b = 120mm and a thickness of t = 12mm , and there may be an edge crack through the full thickness, as shown in Fig. 8.12(c). (a) If the edge crack has length a = 18mm , what tension force P can be allowed for a safety factor against brittle fracture of 3.0 in stress? Solution P = 1 . 259 10 5 N = 125 . 9kN . (2) (b) For the force calculated in (a), what is the safety factor against fully plastic yielding?...
View
Full
Document
This note was uploaded on 09/28/2010 for the course MECHENG 382 taught by Professor Thouless during the Winter '08 term at University of Michigan.
 Winter '08
 Thouless
 Strain, Stress

Click to edit the document details