Question

Flexibility coefficients are used in which of the following method?

• A. Force method
• B. Displacement method
• C. Both force and displacement method
• D. Virtual force method

Hint:

Remember: Force method → flexibility coefficients, Displacement method → stiffness coefficients.

Answer 1

The Correct Option is A

Step 1: Understanding flexibility coefficients.
Flexibility coefficients represent the displacement produced at a point due to a unit force applied at another point.
Step 2: Relation with structural analysis methods.
In the force method (also known as the flexibility method), unknown forces are taken as redundants and compatibility conditions are written using flexibility coefficients.
Step 3: Analysis of options.
(A) Force method: Correct, flexibility coefficients are fundamental to this method.
(B) Displacement method: Incorrect, this method primarily uses stiffness coefficients.
(C) Both force and displacement method: Incorrect, as each method uses different coefficients.
(D) Virtual force method: Incorrect, this method is mainly used for deflection calculations.
Step 4: Conclusion.
Hence, flexibility coefficients are used in the force method.