Direction: Two steel truss members, AC md BC, each having cross sectional are of 100 mm2, are subjected to a horizontal force F as shown in figure. All the joints are hinged.
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The maximum force F in kN that can be applied at C such that the axial stress in any of the truss members DOES NOT exceed 100 MPa is
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- 8.17
- 11.15
- 14.14
- 22.30
- 8.17
Correct Option: B
From Lami’s theorem,
| = | = | ||||
| sin 105° | sin 120° | sin 135° |
⇒ FA = 0.8965 F; FB = 0.732 F
Hence maximum force is FA
| and Stress = | = 100 MPa | |
| Area |
| ∴ | = 100 MPa | |
| 100 |
⇒ F = 11154.48 N or 11.15 kN
