MecMovies 4.0 : M5.4: Deformations in a Three-rod Assembly

scene 6 of 7

The figure shows the deflections suffered by the rigid bar A C B. Joints A and C are separated by 0.7 meters and joints C and B are separated by 0.3 meters. The deflection at joint A is v subscript A which equals 2.40 millimeters. The deflection at joint C is v subscript C. The deflection at joint B is v subscript B which equals 3.60 millimeters. A horizontal line is drawn from A and a diagonal line is drawn passing through A, C and B. Point C is offset from the horizontal by delta and point B is offset from the horizontal by 1.2 millimeters.

Use the principle of similar triangles to find the rigid bar deflection at $C$ .

$\frac{∆}{0.7 m} = \frac{1.20 mm}{1 m} ∴ ∆ = 0.84 mm$

$v_{C} = v_{A} + ∆ = 2.40 mm + 0.84 mm = 3.24 mm$