Two Approaches to the Problem of High-cycle Fatigue of Materials and Structures

Creation of new types of materials and development of new methods aimed at extending the lifetime of structures are two interconnected approaches to solve the problem of metallic structures fatigue. The paper considers a method for estimating the efficiency of damping implemented in metallic structures by means of energy-intensive materials. The results of comparative calculation are given on the ultimate number of transverse vibration cycles in bridge girders. The calculation uses a linear hypothesis of fatigue-caused damage summation and a model of cyclic material degradation. Notable increase of the vibration decrement for foam-filled metallic structures is predicted, with the lifetime of products lengthening as a result.

Analysis of a Broken Pin on the Brake System of a Car Trailer

Fatigue of materials is the degradation process that results from the cyclical dynamic loading of components in combination with other internal or external factors, e.g. corrosion, defects, etc. This paper mainly focuses on the analysis of the causes leading to the damage of a pin in a car trailer´s braking system. The damage of the pin was caused by a few, mutually independent, parameters. Several techniques such as macroscopy, microscopy (light, SEM) and dimension measurement were used for the damage analysis. The material and geometry of the pin were the main issues identified leading to the failure of the part in question.

Characteristics and damage mechanisms of bending fretting fatigue of materials

Fretting fatigue has attracted substantial research interest in recent decades owing to its relevance in a wide range of applications. This paper reviews previous studies and describes ongoing research. Particularly, only a few studies on bending fretting fatigue have been conducted. This review paper emphasizes the effect of bending fretting fatigue of different materials under different operating parameters. In addition, the damage mechanisms with respect to nature of failure of materials are also discussed. This paper can be used as a reference for design and development of modern technologies and selection of appropriate material in industries.

PREREQUISITES TO UNCOVERING THE REGULARITIES OF THE FATIGUE RESISTANCE OF ANCHORAGE OF CURTAIN WALL SYSTEMS

Curtain wall systems are subjected to the influence of air flow, which is changing in its direction and speed. Such an influence gives rise to variable forces, which leads to fluctuating stresses in the structures of curtain wall systems. In case of fluctuating stresses the structural element is destroyed at lower loads, than in case of constant stresses. This fracture is called the fatigue. The fatigue fractures lead to drastic consequences because of their sudden emergence. The fracture mode of structural materials depends on the number of loading cycles. The authors state the notions of multicycle and low-cycle fatigue of materials. Some types of fatigue curves are offered. The authors hypothesize on the absence of horizontal areas of Wehler curve in case of plastic materials.