Maximum embedded fiber length

Zmax maximum embedded fiber length for unstable debond process... 

Fig. 4.39. Comparisons of initial debond stress,

In this method [89], a single fiber is taken and partially embedded in a drop of uncured resin placed on a holder. The resin is then cured with the fiber held upright. The holder, with resin and fiber, is held in a grip attached to the crosshead and then pulled out from the resin. The force pulling the fiber out of the resin is balanced by shear stress at the resin-fiber interface holding the fiber in place. The maximum shear stress occurs as the embedded length tends to zero and is given by ... 

Calculate the maximum and average fiber stresses for glass fibers of diameter 15 pm and length 2 mm embedded in a polymer matrix. The matrix exerts a shear stress of 40 kgficm (3.9 MPa) at the interface, and the critical aspect ratio of the fiber is 50. 

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