N. R. Muzyka

Determination of Damage Accumulated in Structural Materials by the Parameters of Scatter of Their Hardness Characteristics

The authors propose a method for estimating “degradation” of the structural state of materials due to damage accumulation during their operation. The scatter of hardness characteristics determined from the results of mass tests is taken as a damage parameter. The paper presents the findings of experimental studies of the scatter of hardness characteristics of materials after some operation time under cyclic, short- and long-term static loading conditions.

Monitoring of Current State of Pipe Metal in Active Gas Pipelines. Experimental Method and Results

Degradation of the structural state of pipe metal in gas pipelines upon long-term operation is assessed by the proposed hardness method. It is demonstrated that the method provides information needed for monitoring operational reliability of gas pipelines.

Equipment for Testing Sheet Structural Materials under Biaxial Tension. Part 2. Testing by Biaxial Loading in the Plane of the Sheet

We analyze specific features of the design of equipment used for mechanical testing of sheet structural materials under the conditions of biaxial static, cyclic, or dynamic loading. We propose original solutions of the problems related to the fatigue testing of crosslike specimens performed without using complex hydraulic systems and their dynamic testing carried out by using very simple testing machines for uniaxial tension–compression.

Load-carrying capacity of a cracked plate under biaxial tension

The paper presents the findings of an experimental investigation into the possibility of estimating the load-carrying capacity of sheet materials with a central through crack under biaxial tension at low temperatures from the fracture-toughness parameters determined in uniaxial tests.

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.

Assessment of the Service Reliability of Elastoplastic Sheet Materials From Hardness Parameters

A new method for the assessment of the service reliability of cracked metallic sheet materials from hardness parameters is proposed. It has been shown that the state of the material in the pre-fracture zone of a uniaxially loaded specimen, which is acted upon by a stress that is close to the ultimate strength of the material, corresponds to the state of the damaged material in the crack tip zone before crack initiation.

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.

A Study of Damage Accumulation in Sheet Material Under Complex Stress State

The paper provides some results of the investigation of the influence of stress state type on accumulation of dispersed damages in structural carbon steel sheet under repeated static biaxial tensile loading. It is shown that the lowest damage accumulation ability of the metal is observed under biaxial tension with a biaxiality index ranging between 0.25 and 0.3.