V. P. Shvets

Assessment of the Damageability of Low-Carbon Steel Welded Joint Zones under Cyclic Loading Conditions

The paper discusses the results of an experimental study of scattered-damage accumulation in butt-welded joints in St.3sp steel, which is widely used in the assembly of constructions in industry and civil engineering. Welded joints were subjected to inhomogeneous stresses under cyclic bending loading conditions. The degree of metal damage is assessed by the LM-hardness method. A linear correlation between metal damage coefficient and the value of operating bending stresses has been established.

Studies on the Material Damageability by the Scratching Method

The method of studying the material damageability by scratching its surface is proposed. The damage level of the material is assessed by data scattering from multiple measurements of scratch depth differences. The proposed procedure is effected with a device that can analyze the damageability of the material in the article with vertical, inclined or overhead/ceiling surfaces.

Determination of Stresses and Strains in Elastoplastic Deformed Body from Hardness Characteristics

The paper considers the possibility of determining stresses and strains in elastoplastic deformed body from hardness spreading parameters.

Effect of a Loading Mode on Damage Accumulation in the Material

Results of experimental investigation of damage accumulation in different materials in uniaxial tension, compression, and torsion are presented. It is shown that a loading mode determines the arrangement of hardness curves, differing from that of the damage ones. Compression stresses retard damage kinetics, and tangential ones in pure shear lead to more intensive damage accumulation in the material.

Damage assessment of the metal subjected to recrystallization during subsequent deformation

A possible application of the LM-hardness method to assess the state of the metal under thermomechanical treatment is shown. The degree of influence of the initial plastic strain in the metal on its damage depending on the strain level during the subsequent deformation after recrystallization is determined from the data on the scatter of the mass values for the hardness characteristics. It is shown that in the pre-strained metal that has undergone recrystallization, with an increase in repeated plastic deformation, the damage accumulation in the metal structure occurs simultaneously with a decrease in the grain size and the hardness growth. Plastic pre-straining before annealing influences considerably the damage accumulation in the metal: the higher is its level before annealing, the more active is the damage accumulation during the deformation of specimens of the metals after annealing.

Assessment of the limiting levels of dispersed damage in materials under steady-state conditions of static and cyclic loading

The results on the analysis of possible ways of using the concept of dispersed defects in practice when making the admissible damage analysis of structures are presented. The experimental data on the limiting damage to some alloys widely used in mechanical engineering, which are obtained by the LM-hardness method using specimens fractured after the operating time under conditions of creep and cyclic fatigue, are processed and generalized. A linear correlation is found between the levels of the limiting damage and working stresses during the operating time. A version of the procedure for determining the parameters of the correlating equation from the results of basic experiments is proposed.