The IPMash RAS scientists created a new mathematical model which can improve the accuracy of calculating the strength of promising «smart» materials — from shape memory alloys to adaptive composites. The key task is to predict how phase transformations (changes in the microstructure of the material) affect the propagation of cracks and, consequently, the reliability of structures.

Today, the engineers often face the problem of uncertainty in the properties of new materials. The classical strength assessment methods are ineffective due to complex mechanisms of deformation and microstructure changes. Due to the lack of accurate information, one has to compromise: either to make the structure heavier, that can reduce its effectiveness, or to risk its unforeseen behavior.

The Russian researchers have taken an important step by «stitching together» mathematically the macromechanics of deformation, microprocesses (phase transformations in a crystal lattice) and the fracture process. They managed to describe not just a sequence of events, but their interconnectedness: a crack causes a phase transition, and the area of the new phase around the crack, like a shield or a catalyst, changes its growth rate. Thus, the new model combines the processes of deformation, phase transformations and destruction, that is critically important for functional materials which properties change under external impact.

“Our approach allows us to avoid an isolated consideration of phase transitions, deformation, and fracture. We describe them as a single evolving set of phenomena, in which a change in the structure of the material in the vicinity of the crack tip directly dictates the mechanical conditions for its further growth or blocking. This is the key to moving from an empirical selection of materials to their purposeful design with the necessary margin of strength and functionality”, — said Polina Kabanova, a junior researcher at IPMash RAS.

The new model will provide materials scientists and designers with a tool for predicting and control of the durability of products in the aerospace industry, medicine, and power industry. The model may also be used in the development of digital twins of critical structures. The results of the study were presented at an international European Solid Mechanics Conference in Lyon.

The report was recognized as one of the three best poster presentations by young scientists.