Aerospace Structural Analysis and Design Assignment $2024-25$

$1.$ Introduction

A UAV designed to fly at low subsonic speeds has rectangular high$-$aspect wings. The planform

of the starboard wing is shown below in Figure $1.$ The attachment of the wing to the UAV fuselage

can be considered fully built$-$in$.$

$0\mathrm{.}3$m

$3$m

Figure $1.$ Starboard Wing Planform

The cross$-$section at any spanwise station on the wing is as indicated shown below in Figure $2.$

z

x

Cross$-$Section of Wing Spar

y

$5$cm

$6$cm $15$cm $9$cm

Figure $2.$ Cross$-$Section of Aerofoil Section $($not$-$drawn to scale$)$

The cross$-$section of the aerofoil is shown in Figure $2.$ For the purposes of this study, the structural

component to be analysed is the single wing spar which extends the full length of the wing and is

in the form of a hollow rectangular section whose dimensions are $15$ cm and $5$ cm as shown in

Figure $2.$ It has a wall thickness of $3$ mm and is made of an aluminium alloy having the following

properties:

Material density of $2800$ kg$/$m$3$

Young$$s modulus of $90$ GPa

Poisson$$s Ratio of $0\mathrm{.}28$

Tensile strength $($Yield$)$ of $300$ MPa

Tensile strength $($Ultimate$)$ of $340$ MPa

$2$

Hence the components of length $6$cm and $9$cm fore and aft of the spar are not to be considered

in this study from a structural point of view, although they do contribute to the aerodynamics.

Figure $2$ also indicates the axis system. The origin is located at the wing root and centroid of the

wing spar. Ox is positive spanwise, Oy is along the chord and Oz is perpendicular to the chord.

The wing is to be assessed for its structural integrity Figure $1.$ Starboard Wing Planform

e cross$-$section at any spanwise station on the wing is as indicated shown below in Figure $2.$

Figure $2.$ Cross$-$Section of Aerofoil Section $($not$-$drawn to scale$)$