Consider the shown limit load acting on the wing of a passenger aircraft. The dimensions of the
wing and wing-box are also given on the figure. Assume the wing-box carries all the wing loads,
the lift distribution is perpendicular to the beam axis, and the wing-box section does not change
along the wingspan (prismatic beam), and is clamped at the wing root. Ignore the dihedral angle of
the wing. The material of the wing-box is 2024-T6 aluminum alloy (ultimate strength 415 MPA)
a. Integrate the lift distribution over the half wing to calculate its resultant magnitude and
location.
b. If the total weight of the aircraft, INCLUDING all four engines is 1,200 kN, determine the
load factor at this moment.
c. Calculate the maximum bending moment at the wing root section ($M_{max}$)
d. Calculate the second moment of area of the wing-box section, and hence calculate the
maximum bending stress.
e. Determine the Ultimate Stress margin of safety. Comment on the result.
p(x) = 35 (1-0.2x/30) kN/m
