The beam is made from two pieces of wood which are spot glue

The beam is made from two pieces of wood which are spot glued along the longitudinal axis. If each are spot can reliably carry 7516 in shear and are spaced at s=1.5 in, what is the max value of P that avoids delamination of the top board?

Solution

Shear stress of each glue spot = 75/(4*1.50) = 12.5 Psi.

Number of glue spots = 14

Total shear stress of joint = 14*12.5 = 175 Psi

Area of joint = 14*1.5*4 = 84 in²

Maximum value of P to avoid delamination of the top board = 84*175 = 14700 lbs.