An "Allen" wrench is used to loosen a bolt that has a hex-head cross section. As shown in Figure P11-19. This wrench is a 5 mm size and is made of quenched and tempered carbon steel with modulus of elasticity of 200 GPa, Poisson's ratio of 0.29, and yield strength of 615 MPa. The wrench is used to loosen a rusty bolt. To simulate the fixity a surface 2.5 mm in depth from the bottom is held fixed. A total force of 125 N is applied uniformly over 25 mm at the end of the horizontal section of the wrench. Determine the maximum von Mises stress in the wrench. Also determine the maximum displacement. Comment on the safety of the wrench based on whether it will yield or not. (This problem is by Justin Hronek.)

Original model with forces

Dimensions, mm

Figure P11-19 "Allen" wrench showing dimensions, loads, and typical finite element model (By Justin Hronek)

Transcribed Image Text:

Fixed end Forces applied 75 05 R10