If the deflection at free end of a uniformly loaded cantilever beam is...


_______1

_______2
From (2) ⇒

0.02 × 6 = 0.12
substitute in equation (1)

⇒ l = 1.2 m
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If the deflection at free end of a uniformly loaded cantilever beam is...
Understanding the Problem
In this problem, we are dealing with a cantilever beam subjected to a uniform load. We have two key pieces of information:
- The deflection at the free end of the beam (δ) is 18 mm.
- The slope of the deflection curve at the free end (θ) is 0.02.
The goal is to find the length of the beam (L).
Formulas for Cantilever Beam
For a uniformly loaded cantilever beam, the relationships between deflection, slope, and length can be defined as follows:
- The formula for deflection at the free end:
δ = (w * L^4) / (8 * E * I)
- The formula for slope at the free end:
θ = (w * L^3) / (3 * E * I)
Where:
- w = uniform load per unit length
- E = modulus of elasticity
- I = moment of inertia
Relating Deflection and Slope
From the two equations, we can derive a relationship between deflection and slope. By eliminating w, we can express L in terms of δ and θ.
By manipulating the equations, we arrive at a simplified relation:
L = (3 * δ / θ)^(1/3)
Calculating Length of the Beam
Substituting the given values:
- δ = 18 mm = 0.018 m
- θ = 0.02
L = (3 * 0.018 / 0.02)^(1/3)
Calculating this gives us:
L = (2.7)^(1/3) ≈ 1.2 m
Conclusion
Thus, the length of the cantilever beam is approximately 1.2 m, confirming that the correct answer is option 'C'.