JNTU
JNTU B.Tech III AEROSPACE VEHICLE STRUCTURES II Previous Question Paper (July/August - 2023 - R13)
Question paper consists of Part A, Part B. Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What is a complete diagonal tension field beam?
Answer
A complete diagonal tension field beam is a thin-webbed beam where the web is so thin that it buckles under very low shear loads. In this state, the web is assumed to carry no compressive stress, and the entire shear load is carried by the tension stresses acting along the diagonal direction of the web panels, effectively acting like a Pratt truss.
Explain instability of stiffened panels.
Answer
Instability in stiffened panels occurs when the thin skin between stiffeners buckles under compressive or shear loads before reaching the material's yield strength. This buckling can lead to local buckling of the skin, inter-rivet buckling, or general instability where both the skin and the stiffeners buckle together, significantly reducing the load-carrying capacity of the structure.
What is neutral axis?
Answer
Sign in to view the complete answer paper.
Establish the relation between bending moment and shear force.
Answer
Sign in to view the complete answer paper.
Define the terms: Shear centre and centre of twist.
Answer
Sign in to view the complete answer paper.
Why the moment of inertia of a boom section is zero?
Answer
Sign in to view the complete answer paper.
Define the term loading discontinuities in beams.
Answer
Sign in to view the complete answer paper.
How warping will occur in open section beams?
Answer
Sign in to view the complete answer paper.
What are the functions of wing ribs?
Answer
Sign in to view the complete answer paper.
How does a thin rectangular strip undergo warping across its thickness when subjected to torsion?
Answer
Sign in to view the complete answer paper.
Part B
Describe an experiment to determine the critical load of buckling for a flat panel.
Answer
Sign in to view the complete answer paper.
Discuss the significance of Wagner’s theory of beams.
Answer
Sign in to view the complete answer paper.
Derive the equations to find out primary and secondary warping of an open cross section beam subjected to torsion.
Answer
Sign in to view the complete answer paper.
The cross-section of a beam has the dimensions shown in figure 1. If the beam is subjected to a negative bending moment of 100 kNm applied in a vertical plane, determine the distribution of direct stress through the depth of the section.
Answer
Sign in to view the complete answer paper.
Calculate the shear flow distribution in the channel section shown in figure 2. Shown produced by a vertical shear load of 4.8 kN acting through its shear centre. Assume that the walls of the section are only effective in resisting shear stresses while the booms, each of area 300mm2, carry all direct stresses.
Answer
Sign in to view the complete answer paper.
The thin-walled single cell beam shown in figure 3 has been idealized into a combination of direct stress-carrying booms and shear-stress-only-carrying walls. If the section supports a vertical shear load of 10 kN acting in a vertical plane through booms 3 and 6, calculate the distribution of shear flow around the section.
Answer
Sign in to view the complete answer paper.
Discuss shear stress distributions of a closed section beam built in one end and subjected to bending.
Answer
Sign in to view the complete answer paper.
Elaborate the issues posed by shear lag in the analysis of wide, shallow and thin-walled beams.
Answer
Sign in to view the complete answer paper.
Derive the equation to find out shear flow in a tapered wing.
Answer
Sign in to view the complete answer paper.
Calculate the deflection at the free end of the two-cell beam shown in figure 4 allowing for both bending and shear effects. The booms carry all the direct stresses while the skin panels, of constant thickness throughout are effective only in shear. Take E = 69,000 N/mm2 and G = 25,900 N/mm2.
Answer
Sign in to view the complete answer paper.