Therefore:

of the bend in radians. The radian relates the length of

the arc generated to the size of the angle. For the

ba = 3.250 1.57 = 5.10 inches

purpose of computing bend allowance, the number of

radians per degree of bend is 0.017453. Thus, the

EXAMPLE 2 (fig. 13-50)--What is the bend

formula for bend allowance is:

allowance for a 180-degree bend which is to be made

in a length of l/2-inch stock?

ba = r R

r = 1.0 + 0.250 = 1.25 inches

Where:

8 = 0.017453 180 = 3.14 radians

ba = bend allowance

Therefore:

r= radius of the neutral axis of the bend

ba = 1.25 3.14 = 3.925 inches

EXAMPLE 1 (fig. 13-49)--What is the bend

allowance for a 90-degree bend with a 3-inch

radius which is to be made in plate that is l/2 inch

Much of your work will consist of repairs and

thick?

alterations made to the existing ship's structures.

r = 3.00 + 0.250 = 3.250 inches.

Repairs are different from alterations in that the design

(Remember you must add one-half the thickness of the

of the ship's structure is not changed by repairs.

plate to be bent to the radius of the bend.)

For example, if you remove a deteriorated section

8 = 0.017453 x 90 = 1.57 radians

of a watertight bulkhead and install a new section, it is

13-43