Question

In a Semi-Monocoque wing undergoing upward bending, which of the following is true regarding the wing skins?

• A. The top skin is in compression and the bottom skin is in tension
• B. The skins carry only shear loads and no normal stresses
• C. Both skins are in pure tension
• D. The top skin is in tension and the bottom skin is in compression

Hint:

For an aircraft wing under positive lift, \[ \boxed{ \begin{aligned} \text{Top Skin} &\rightarrow \text{Compression} \text{Bottom Skin} &\rightarrow \text{Tension} \end{aligned} } \] The spars mainly resist shear while the skins resist bending stresses.

Answer 1

The Correct Option is A

Step 1: Recall the bending behavior of a wing. During flight, the lift force bends the wing upward. This upward bending produces bending stresses in the wing skins.

Step 2: Determine the stresses in the skins. For upward bending, \[ \boxed{ \text{Top skin } \rightarrow \text{Compression} } \] and \[ \boxed{ \text{Bottom skin } \rightarrow \text{Tension}. } \] Therefore, \[ \boxed{\text{The top skin is in compression and the bottom skin is in tension}.} \] Hence, \[ \boxed{(A)} \] is the correct answer.