A comparative analysis of the stress-strain state of disc specimens in assessing the structural strength of materials

A study of the stress-strain state (SSS) of disc specimens has been conducted when testing specimens with stress concentrators (grooves). The research has shown that the truncation of circular discs along two symmetrical chords makes it possible to change the type (the ratio of principal stresses) of SSS that occurs at the destruction site. Therefore, these specimens can be used to assess the structural strength of materials on standard single-drive testing machines, taking into account the real type of SSS that occurs in the bearing elements of machines. The results of numerical SSS modeling have been used to build the dependences of the SSS type and level on geometric parameters of specimens. Geometrical parameters can be chosen for a certain SSS type to assess both the static and fatigue strengths of materials used in the manufacture of bearing elements.

Theoretical research of dimensional optimization and choice of material strength in steel-concrete composite beams

The aim of this study is to find out how the change of individual parameters will affect the flexural strength of steel-concrete composite beams. The project was focused on the choice of strength of materials and the choice of dimension, specifically the height of the concrete slab and the size of the steel profile. The research aim is to reveal which parameters have dominant influence on the flexural strength and thus facilitate the optimization of the design in practice.

Surface and Interface Studies for Improved Performance of Metallic Parts and Devices

This work is to reveal and present some contemporary surface treatment methods used in view of improving performance of parts of a variety of metals and alloys. Stainless steels and titanium alloys are with the group of particular focus, important for medical implants in chirurgy and instruments used in dentistry. Improved, anti-corrosion properties and mechanical strength of materials are the primary features for examination.

From Galileo to Navier and Clapeyron

Galileo (1564-1642), in his well-known Discorsi (Galileo, 1638), briefly turning his attention to the fracture of a beam, starts an interesting discussion on the beam’s breakage as well as its location. Could the section and breaking point of a beam have been determined beforehand? Furthermore, is it specific to the material? What Galileo did was not merely challenge a physics problem, but the prevailing knowledge of his time: namely, Aristotelianism on one hand, and Nominalism on the other. As a matter of fact, must the breakage of an element be treated as a universal or is it particular to a given material? The present essay aims to prove how Galileo, confronting the structural problem and bringing it into the realm of science, was not just raising a problem but, using Salviati’s words, he also established what actually takes place. Many years later, with the progress of physics, strength of materials and theory of structures, figures such as Claude Navier (1785-1836) and Benoît Clapeyron (1799-1864) confirmed once again that the Pisan turned out to be right. This article intends to combine technical fields such as strength of materials and theory of structures with others like the history of science and philosophy proper. A cooperative approach to these disciplines can be doubtlessly helpful to improve the knowledge, learning and teaching of their different curricula, giving the reader a global, holistic perspective.

MODELING THE PROCESS OF INSPECTION OF REINFORCED CONCRETE SUPPORTS OF TECHNOLOGICAL OVERPASSES

The paper presents the process of assessing the technical condition of reinforced concrete supports of existing technological overpasses. The characteristics of overpasses are given. Defects identified in the process of assessing the technical condition are shown. The paper describes the control of concrete strength by the non-destructive method of elastic rebound using the Digi Shmidt 2000 device and the determination of the concrete cover thickness and the location of reinforcement by the magnetic method using the Profometer-5S device. The layout of the working reinforcement in the reinforced concrete supports of the overpass section has been determined. The results of verification calculations of the structures of technological ramps are given, taking into account the revealed defects and damages, the strength of materials and the specified actual loads. Proposals are given for improving the performance of concrete of reinforced concrete supports of overpasses.