The collar is rigidly attached to bar A . The cylindrical bar A is 80 mm in diameter and its shear modulus is G = 66 GPa. There are gaps b = 2 mm between the arms of the collar and the ends of the...

The collar is rigidly attached to bar
A. The cylindrical bar
A
is 80 mm in diameter and its shear modulus is
G
= 66 GPa. There are gaps
b
= 2 mm between the arms of the collar and the ends of the identical bars
B
and
C. Bars
B
and
C
are 30 mm in diameter and their modulus of elasticity is
E
= 170 GPa. The bars
B
and
C
are stretched until they come into contact with the arms of the collar and are welded to them. If bar
A
is made of a material that will safely support a tensile or compressive normal stress of 170 MPa, what is the largest safe value of
b?