The ability of structural elements withstanding impact and shock-wave loading has been considered. The dynamic stress-strain state of structural elements at the stage of occurrence of large elastic-plastic deformation and fracture has been investigated, and different criteria of the structure strength has been used. The numerical and experimental results have been compared.

To ensure the dynamic strength of modern constructions, protective elements are used. Studies have shown that even with the use of double-layer elements from similar materials, multilayer elements have enhanced protective properties with a smaller overall thickness compared to single-layer elements. Even greater effect is achieved when using layers of different materials. These features are widely used in the creation of linings to strengthen the bodies of gas turbine engines when exposed to fragments of blades and foreign objects. Numerical studies of the stress-strain state of three-layer element from two thin layers of a titanium alloy and an average ceramic layer under the influence of projectile with different velocities are carried out. The top layer of the titanium alloy perceives the main local load and plastic deformations occur up to the formation of the crater. In the average ceramic layer, the extensive deformations develop, during which the basic energy of impact is absorbed. The third layer limits the velocity of deformation and increases the protective properties of the element. Thus, it is shown that the multilayer elements can have improved protective properties with a general reduction of the weight of structure.

Abstract. Protective structures such as process chambers, protective boxes, facing elements of vehicles, personal protection equipment, motors cases etc. widely used in modern technology has been tested in the following project. Under the influence of impact loads, the three-dimensional dynamic stress-strain state with finite dynamic displacements and deformations has arised. The deformations occur in the elastic-plastic stage. In the analysis of the high-rate deformations, the dynamic properties of the materials, which are determined based on experimental data should be taken into account. The dynamic stress state of structural elements depends essentially on the dynamic properties of the materials used. The problem is solved using the finite element method, which takes into account the specifics of the process. Boundary conditions in the element nodes must satisfy the equality movement as well as derivatives. The formed function allows to describe continuous and smooth stress changes. The numerical analysis of the dynamic stress-strain state of structural elements under impact loads, takes into account different dynamic properties of the materials. A series of numerical calculations allows to reveal the features of high-rate deformation elements of protective structures and makes recommendations to improve their dynamic strength under different loading conditions.

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