Design of Fixtures

Design Of L Bracket• Design of a simple “L” shaped

bracket:• The bracket is subjected to a load

of 10 kg at point ‘B’ and fixed by bolt at point ‘A’. For initial design we have started with 5 mm thick plate.

Calculating maximum bending moment

• In order to find out the section where the maximum bending stress occurs, we need to draw bending moment diagram.

• Let’s consider our case as a cantilever beam (though it is not a proper cantilever beam but for the initial analysis we are considering this as a cantilever beam).

• From the bending moment diagram we can easily point out the location of maximum bending moment and the value of the maximum bending moment is 750 kg-mm.

• So, the maximum bending moment M=750 kg-mm

• The area moment of inertia for this section = (bd^3)/12

• = 1041.667 mm4

Calculating bending stress• The classic formula for determining the bending

stress in a member is: f/y=M/I

f = M.y/ I= 750 X 2.5/1041.667 kg/mm2= 1.8 kg/mm2

• If we consider a steel with yield strength is 25 kg/mm2, then we can see that stress generated in the clip is substantially low , so we have the chance to further reduce the thickness of the clip.