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Unformatted text preview: there is a limitation to the free expansion. Example
► Prob. 453 (variation). A 10mm. steel bolt (Est = 200 GPa) is surrounded by bronze sleeve with 10 mm. ID and 20mm. OD(Ebr = 100 GPa). Assume bolt and sleeve length is 100mm. If the nut is snug and the temperature is raised 70 °C what are the stresses in the bolt and sleeve? αsteel = 12ˣ10-6/°C αbronze =
/°C Stress Concentration
► ► ► Stress generated at the vicinity of discontinuities such as holes, corners, threads, etc. are much larger than the nominal stress based on the uniform stress distribution. When analyzing these types of problems, we are usually interested in the maximum stress value and where it occurs. We introduce the stress
concentration factor, K, which relates the maximum stress to the nominal stress. Stress Concentration Stress Concentration ► Stress Concentration Factor σ max
σ ave ► ► σave =P/Asmallest The nomimal strss is The nomimal strss is ave =P/A
determined using the smallest cross sectional area (at the mid
point of the hole,...
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