Ejercicios tutoria1 2017

1. Ejercicio 1: (2.15)
The inclined member AB of a timber truss is framed into a 4 x 6 -in. bottom chord, as
shown in figure. Determine the axial compressive force in member AB when de average
shearing stress parallel to the grain at the end of the bottom chord is 225 psi.
Ejercicio 2: (3.9)
A rigid steel plate A is supported by three rods as shown in Figure. There is no strain in the
rods before the load P is applied. After load P is applied, the axial strain in the rod DE is
800 µin/in.
Determine:
a. The axial strain in rods BC
b. The axial strain in rods BC if there is a 0.006-in clearance in the connections
between plate A and rod BC before the load is applied.

2. Ejercicio 3:
A pressurized circular cylinder has a sealed cover plate fastened with steel bolts (see figure).
The pressure p of the gas in the cylinder is 290 psi, the inside diameter D of the cylinder is
10.0 in., and the diameter dB of the bolts is 0.50 in. If the allowable tensile stress in the bolts
is 10,000 psi, find the number n of bolts needed to fasten the cover.
Ejercicio 4:
A bar of rectangular cross section is subjected to an axial load P (see figure). The bar has
width b _ 2.0 in. and thickness t _ 0.25 in. A hole of diameter d is drilled through the bar to
provide for a pin support. The allowable tensile stress on the net cross section of the bar is
20 ksi, and the allowable shear stress in the pin is 11.5 ksi.
(a) Determine the pin diameter dm for which the load P will be a maximum.
(b) Determine the corresponding value Pmax of the load.