Modeling of crack nucleation in covering

What is it about?

Based on the suggested design model that takes into account the presence of damages (area of the weakened interparticle bonds of the material) in the covering, a method for calculating the covering parameters under which the crack initiation happens is developed. Knowing the main values of critical parameters of crack initiation and influence of materials properties on them, the crack initiation phenomenon may be grounded controlled by means of design–technological decisions in the designing stage. The numerical realization of the obtained equations allows to solve the following practically important design problems: To estimate the guaranteed resource of the pair ‘‘covering-elastic base’’ with regard to expected defects and loading conditions; To establish the admissible level of deficiency and maximal value of workloads providing sufficient reliability reserve; To choose materials with necessary complex of statistical and cyclic crack resistance characteristics.

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Why is it important?

Experimental data of practice of exploitation of the pair ‘‘covering-elastic base’’ convincingly show that in the stage of design it is necessary to take into attention the cases when in there may arise cracks. The existing methods of strength analysis of the pair ‘‘covering-elastic base’’ ignore this circumstance. Such a situation makes impossible to design the pair ‘‘covering-base’’ of minimal specific consumption of materials under guaranteed reliability and durability. In this connection it is necessary to realize the limiting analysis of the pair ‘‘covering-elastic base’’ in order to establish ultimate loads under which the crack initiation happens in the covering. The size of the ultimate minimal prefracture zone under which the crack happens should be considered as design characteristics of the covering material.