Image of the plate is missing, so i have attached it.
Answer:
A) t = 7.854 mm
B) σ = 26.67 MPa
Explanation:
A) From shearing of rivet, formula for pressure is;
P = τ•A_rivets
Where;
τ is allowable stress
A_rivets is Area of rivet
We are given:
τ = 60 MPa
Diameter; d = 20 mm
A_rivets = πd²/4 = π × 20²/4 = 100π
Thus;
P = 60 × 100π
P = 6000π N
From bearing of plate material, we can calculate pressure as;
P = σ_b•A_b
We are given;
σ_b = 120 MPa
A_b is area of plate = 20t
Where t is the thickness
Thus;
6000π = 120 × 20t
t = 6000π/(120 × 20)
t = 7.854 mm
B) Largest average tensile stress is given by the formula;
σ = P/A
Where A = 110t - 20t
A = 90t
A = 90 × 7.854
Thus;
σ = 6000π/(90 × 7.854)
σ = 26.67 MPa
