On one approach to the assessing of the adhesive layer strength in a layered composite

The problem of a stress-strain state of a composite with undefined geometry of the face break of the adhesive layer is formulated and solved. A concept of the interactive layer is used which implies uniformity of the stress-strain state over adhesive layer thickness. In accordance with Timoshenko's hypotheses for displacements of the bearing layers, the problem is reduced to a system of linear differential equations. The reliability of the obtained analytical solution is confirmed by the numerical calculation with no additional hypotheses introduced. The product of the specific free energy by layer thickness, referred to as an energy product, is revealed to be applicable as a criterion of the adhesive layer destruction. On the basis of the analytical solution, a threshold value of the adhesive layer thickness is determined. A decrease in the latter does not affect the energy product value. Thus, employing the energy product as a criterion of destruction, calculations can be performed at any value of the adhesive layer thickness arbitrarily chosen in the range of the energy product suability.