HW#4
Read/Study:

Chapter-4 Deflection and Stiffness
o Spring rate 4-1
o Tension, compression, torsion 4-2
o Strain Energy 4-7
o Castigliano’s theorem 4-8
o Skip the following sections
 4-11 Compression Members
 4-12 Long Columns
 4-13 Intermediate Columns
 4-14 Eccentric Loading
o Shock and Impact 4-17
FYI Maple Output (You don’t have to do the integrals by hand)
Problem #1
Given: The design of a L-shaped pull-up bar (the support is a vertical wall)
o
The cross-section of the bar is tubular with the OD of 2 inches and wall thickness of 1/4
inch. The material is steel with E=30 Mpsi.
Find: The maximum deflection of the end of the bar if a 250 lb person pulls up with a maximum
acceleration of 0.25g while hanging from the end of the bar. {ANS: 0.275 in}
1 ft
2 ft
W=250 lbs
Problem #2
Given: The design of a L-shaped pull-up bar (the support is a horizontal ceiling)
o
The cross-section of the bar is tubular with the OD of 2 inches and wall thickness of 1/4
inch. The material is steel with E=30 Mpsi.
Find: The maximum deflection of the end of the bar if a 250 lb person pulls up with a maximum
acceleration of 0.25g while hanging from the end of the bar. Assume the entire weight hangs
from the end of a single bar.
The inner radius of the curved bar is 6 inches. Assume the deflection formula for the curved
beam presented in class applies. {1.65 in}
0.5 ft
4 ft
W=250 lbs