Classical guitar necks were submitted to 40, 65 and 80% relative humidity (RH) during time periods ranging from 24 h to several months, and moisture-induced deformations were observed. Different types of classical guitar necks were investigated in terms of structure and reinforcement. The influences of the wood species and the neck reinforcements on the moisture content (MC)-induced deformation were in focus. First, before humidity exposure in the climatic chamber, the relative positions of three points marked on each sample were measured with a control ruler and noted. After exposure, the displacement of the reference points on the samples were verified periodically. The differences between the measurements in different stages and reference positions were calculated, resulting in relative displacement data of the measured points. During the experiments, the MC of the sample was monitored by weighing. The variation of RH leads to dimensional instability and moisture-induced stresses of the guitar necks, which affect the acoustic quality of a guitar. Steel enforcement of the guitar neck improves this situation.

This paper reports experimental and theoretical result derived from research on steel structural elements’ fire-protection with intumescent paint. The experimental results were obtained by means of an original testing bench, briefly described below and some basic cases, i.e., horizontally and vertically disposed, massive and square-tubular cross-sectioned, reduced-scale straight bars heated at one end. By means of the thermocouples mounted along the bars, the temperature distribution laws were monitored, depending on the heated end’s nominal temperature. The paper describes an original approach to the temperature distribution evaluation by means of some new parameters, based on the temperature distribution laws experimentally obtained with reduced-scale models. We involved the least-square method (LSM) and the curve-fitting one in order to obtain a more accurate temperature distribution law compared to the experimentally obtained ones. We also introduced some new parameters in order to define the amount of heat loss in a more accurate way. Based on the results obtained, the authors suggest that this approach to the temperature distribution law can be efficiently applied in further thermal analyses, for both 2D and 3D structures. The paper also includes a thorough analysis of “m” variation along the square-tubular-cross-section, reduced-scale straight bars, and similar new approaches are proposed by the authors. The sub-goals of this investigation were (1) to obtain useful correlations between the magnitudes of the massivity $\zeta =P/A$ and the parameter “m” along the bar, and (2) to analyze, on reduced-scale models, the heat distribution laws on unprotected and intumescent-paint-protected 2D and 3D steel structures.

Towing systems are an important component in the automobile industry, having to meet specific quality and resistance conditions. In most cases, the towbar is made of steel. Decreases in vehicle weight and manufacturing price mean that, in this field, research is also being conducted in order to replace the materials that make up the towbar and replace the steel with composite materials or aluminum alloys. In this paper, research was performed on towing systems built from other materials, and the obtained results were compared with those of steel systems. Theoretical calculations and experimental results made it possible to obtain a database and recommendations for the use of new and composite materials. The experimental tests validated the theoretical results obtained. Five towing systems made of different materials were studied. The results of the research are emphasized through recommendations regarding the manufacturing of towing systems.

In this contribution, the authors continued their initial study on the efficiency of the analysis of experimentally obtained temperature curves, in order to determine some basic parameters that are as simple and reliable as possible, such as “m”, the heat transfer coefficient. After the brief review of the previous results, on which the present article is based, the authors offered a brief argumentation of the importance of dimensional methods, especially the one called modern dimensional analysis, in these theoretical-experimental investigations regarding the propagation of the thermal field of structural elements with solid sections, and especially with tubular-rectangular sections. It could be concluded that modern experimental investigations mostly follow the behavior of models attached to the initial structures, i.e., prototypes, because there are clear advantages in this process of forecasting the behavior of the prototype based on the measurement results obtained on the attached model.

The mechanical behavior of a composite is determined by the value of the engineering constants for the composite under consideration. If we study a homogeneous and isotropic composite, then two engineering elastic constants are needed to characterize the material; if we refer to a transversely isotropic composite, five elastic constants are needed. For more complex materials it can be necessary to determine more elastic constants in order to obtain the behavior of the composite in practical applications. In this paper, the authors present the main classic methods for calculating the engineering constants of a fiber composite material that are used in parallel with the finite element method (FEM) and highlight the advantages (and disadvantages) of using direct FEM to achieve this. The arrangement of identical fibers provides regularities that allow for easier calculations and, in some cases, the application of simple methods. The results that have already become classics, current results, and unusual examples are all critically presented in this study. All of these findings are discussed in relation to the use of the FEM, either as the primary calculation method or as a useful aid in the application of classical methods. The paper focuses on presenting research on the use of FEM for this purpose. For the different approaches discussed and for the area overall, future research directions are emphasized.