GATE 2025 ME – Question 61

Machine Design · Bolted, riveted and welded joints · 2 marks · Numerical answer

Two plates of thickness 10 mm each are to be joined by a transverse fillet weld on one side and the resulting structure is loaded as shown in the figure below.

If the ultimate tensile strength of the weld material is 150 MPa and the factor of safety to be used is 3, the minimum length of the weld required to ensure that the weld does NOT fail is ______ mm (rounded off to 2 decimal places).

Two overlapping plates of thickness 10 mm, joined by a single transverse fillet weld along one edge, and pulled apart by a 5 kN force at each end.

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Correct answer: 14.07 to 14.21

Explanation

The allowable stress is $\frac{150}{3} = 50$ MPa. The weld leg is equal to the plate thickness, 10 mm, so the throat is $0.707 \times 10 = 7.07$ mm. The throat area is $7.07 \times L$. Setting $\frac{5000}{7.07L} = 50$ gives $L = \frac{5000}{353.6} = 14.14$ mm.