Author: admin

An S-shaped block used in force measurement as shown in
Figure P11–16 is to be designed for a pressure of 1000 psi applied uniformly to
the top surface. Determine the uniform thickness of the block needed such that
the sensor is compressed no more than 0.05 in. Also make sure that the maximum
stress from the maximum distortion energy failure theory is less than the yield
strength of the material. Use a factor of safety of 1.5 on the stress only. The
overall size of the block must fit in a 1.5-in.-high, 1-in.-wide, 1-in.-deep
volume. The block should be made of steel.

A device is to be hydraulically loaded to resist an upward
force P = 6000 lb as shown in Figure P11–17. Determine the thickness of the
device such that the maximum deflection is 0.1 in. vertically and the maximum
stress is less than the yield strength
using a factor of safety of 2 (only on the stress). The
device must fit in a space 7 in. high, 3 in. wide, and 2.3 in. deep. The top
flange is bent vertically as shown, and the device is clamped to the floor. Use
steel for the material.

An ‘‘Allen’’ wrench is used to loosen a bolt that has a
hex-head cross section. As shown in Figure P11–18. 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 compliments of
Justin Hronek.)

A fork from a forklift is constrained by two bars (not
shown) that fit into each L-shaped appendage on the vertical part of the fork
as shown in Figure P11–20. The fork is made of AISI 4130 steel with E = 206:84
GPa, v = 0:30, and a yield strength of 360 MPa. The fork is loaded with 46,189
N/m
2
of surface traction on the top surface.
How much will the fork deflect, and what is the maximum von
Mises stress? What is the factor of safety against yielding of the material?
(This problem is compliments of Jay Emmerich.)

The hitch shown in Figure P11–22 is used on an International
496 disk. The hitch is made of cold drawn 1018 steel with E = 29
10
6
psi. The yield strength of the material is 53,700 psi. The disk requires 200 hp
to pull at 6 mph. The total force of 12,500 lbf in the hitch is then determined
from force equal to power divided by velocity. Determine the maximum von Mises
stress and the deflection of the hitch under the load. In the model, use two
6250 lbf applied to each side of the hitch and fix the nodes at the ends of the
attachment to the disk frame (as shown in the finite element model). (This
problem is compliments of Byron Manternach.)

A swivel C bracket shown in Figure P11–23 is mounted to a
ceiling of a building and has a speaker (not shown) of 20 lbf hanging from each
mounting hole. The mounting bracket is made of A 36 steel with a modulus of
elasticity of 29
10
6
psi, Poisson’s ratio
of 0.29, and yield strength of 36,000 psi. Determine the maximum von Mises
stress and deflection in the bracket. (This problem is compliments of Tyler
Austin and Kyle Jones.)

The lower arms of a front-end loader are shown in Figure
P11–24. The loader material is AISI 1010 cold drawn steel with a modulus of
elasticity of 29:7
10
6
psi and Poisson’s
ratio of 0.29. The yield strength of the material is 44,200 psi. In the finite
element model, the back faces of the top horizontal members are fixed.
Determine the maximum force that can be applied to the bottom of the left arm
to cause yielding of the arm. You may want to try loads that are vertical
(y-directed) and lateral (z-directed). (This problem is compliments of Quentin
Moller.)

A bicycle stem is shown in Figure P11–25. The stem attaches
the handlebars to the steerer tube of the fork. The stem is made of 7075-T6
aluminum alloy with yield strength of 504 MPa. The load of 1200 N is spread
over the mounting surface to the handlebar in the x-y plane and acts at a 45o
angle from the axis of the stem. The inner surface of the stem that attaches to
the steerer tube is fixed in translation in the y-direction and in rotation about
the y-axis. Determine the largest von Mises stress and its location on the
stem. (This problem is courtesy of Stephen Wilson.)