Rivets

Rivets are made of wrought iron or soft steel. It is used as fastener for joints in building, bridges, boilers, tanks, ships, and miscellaneous framework.

Types of Riveted Joints

1.  Lap Joints

a. A single riveted lap joint

b. Double riveted lap joint

c. Triple riveted lap joint

2. Butt Joint

a. Single riveted butt joint

b. Double riveted butt joint

c. Triple riveted butt joint

Common Assumptions

1. The load is distributed among the rivets according to the shear areas.

2. There is no bending stress in the rivets.

3. The tensile stress is equally distributed over the projected area of the rivets.

4. In a rivet subjected to double shear, the shear is equally distributed area of the rivet.

5. The crushing pressure is equally distributed over projected area of of the rivet.

6. The holes into which the rivets are given so not weaken the member if it is in compression.

7. After they have been driven, the rivet completely fills the holes.

8. Friction between adjacent surfaces does not affect the strength of the joints. 

For riveted Joints

               

1. Tangential Design Stress

S_t = P_i D_i

        2 t e

Where:

                S_t = tangential Stress , Mpa or psi

                P_i = inside pressure, Mpa or psi

                D_i = inside diameter, mm or in.

                t = wall thickness, mm or in.

                e = efficiency

2.  Factor of Safety

FS = S_tu / S_t

Where:

                S_t = tangential Stress , Mpa or psi

                S_{tu =} ultimate tensile, Mpa or psi

                FS = factor of safety

3.  Efficiency of the joint for single riveted but joint

e = p – d  X 100

         p

Where:

                p = pitch, mm or in.

                d = rivet diameter, mm or in.

                e = efficiency