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Three wooden planks are fastened together by a series of
Chapter 1, Problem 1.20(choose chapter or problem)
Three wooden planks are fastened together by a series of bolts to form a column. The diameter of each bolt is 12 mm and the inner diameter of each washer is 16 mm, which is slightly larger than the diameter of the holes in the planks. Determine the smallest allowable outer diameter d of the washers, knowing that the average normal stress in the bolts is 36 MPa and that the bearing stress between the washers and the planks must not exceed 8.5 MPa.
Questions & Answers
QUESTION:
Three wooden planks are fastened together by a series of bolts to form a column. The diameter of each bolt is 12 mm and the inner diameter of each washer is 16 mm, which is slightly larger than the diameter of the holes in the planks. Determine the smallest allowable outer diameter d of the washers, knowing that the average normal stress in the bolts is 36 MPa and that the bearing stress between the washers and the planks must not exceed 8.5 MPa.
ANSWER:
Step 1 of 6
We have to find the smallest allowable diameter of the washer. As we decrease the diameter of the washer, the bearing area decreases and corresponding stress in the washer increases.First we will calculate the maximum possible tensile force in the bolt based on allowable tensile stress. Using the allowable bearing stress for washer and maximum tensile force in the bolt, we will calculate the minimum bearing area possible which gives us the smallest diameter of the washer.