Question

Knowing that theholw has a diameter of 9 mm, determine (a) the radius rf of the filler from which the same maximum stress occurs at the hole A and at the fillets, (b) thecorresponding maximum allowable load P if the alloable stress is 100 MPa.

Answer 1

Find the least cross-sectional area under stress at the drilled hole.

Here, is the breadth of the plate, is the diameter of circular hole, and t is the thickness of the plate.

Substitute for , 9 mm for t, and for

Calculate the ratio of

Here, r is radius of the hole.

Substitute for and for .

Obtain the value of stress concentration factor at from the Figure 2.60 (a)” Flat bars with holes” in the textbook.

Stress concentration factor,

(b)

Write the equation for average normal stress to find the maximum allowable load.

Here, is the maximum allowable stress and allowable load is .

Substitute for , for and for

Therefore, the maximum allowable load is .

Find the cross-section area at the right side part of the plate.

Here, is the breadth of right side of the plate and thickness of the plate is .

Substitute for and 9 mm for t.

Calculate the ratio of D/d.

Calculate the stress concertation factor at the fillet.

Substitute for for , and for A

Obtain the value of at from the Figure 2.60 (b)” Flat bars with fillets” in the textbook.

(a)

Calculate the radius of the fillet.

Substitute for .

Thus, the radius of fillet is .