GATE MT 2016 Q.48 A glass plate has two parallel cracks. One of them is an internal crack of length 5 μm and the other is a surface crack of length 3 μm. A tensile stress is applied perpendicular to the crack surfaces. The fracture stress (in MPa) is _______. Given data (for glass plate): Young’s Modulus = 70 GPa Surface energy per unit area = 1 J.m-2
GATE MT 2016 Q.48 A glass plate has two parallel cracks. One of them is an internal crack of length 5 μm and the other is a surface crack of length 3 μm. A tensile stress is applied perpendicular to the crack surfaces. The fracture stress (in MPa) is _______. Given data (for glass plate): Young’s Modulus = 70 GPa Surface energy per unit area = 1 J.m-2
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Correct answer is 121.8 Given that, internal crack( C1) of length 2.5 μm surface crack (C2) of length 3 μm As per question C2> C1 We know that, Griffith's theory, σf= √2Eγs/πC2 σf= √2×70×109×1 /π×3×10-6 = 121.8 MPa
Correct answer is 121.8
Given that, internal crack( C1) of length 2.5 μm
surface crack (C2) of length 3 μm
As per question C2> C1
We know that, Griffith’s theory, σf= √2Eγs/πC2
σf= √2×70×109×1 /π×3×10-6 = 121.8 MPa
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