VOJNOTEHNIČKI GLASNIK

Introduction/purpose: Temperature and time-dependent effects such as concrete shrinkage and creep significantly affect the behavior of steel-concrete composite beams. Hence, taking into account the demands brought by these additional effects is necessary. This necessity has resulted in various theoretical and numerical research studies. This article proposes an analytical tool capable of predicting a new redistribution of stresses brought by the combined action of temperature and concrete shrinkage in composite steel-concrete beams in partial shear connection. In this work, the partial shear connection at the steel-concrete interface is taken into account according to the degree of connection (N/Nf).

Methods: This involves reformulating the model proposed in 2024 by Rahal et al analyzing the behavior of composite steel-concrete beams in full shear connection under the effect of temperature and concrete shrinkage. In this present study, the main contribution is the introduction of the effect of the connection degree (N/Nf) at the steel-concrete interface, thus leading to an analytical model capable of predicting additional stresses brought by shrinkage and temperature in composite steel-concrete beams in partial shear connection.

Results: When referred to the model proposed in 2024 by Rahal et al, the results from this current approach are satisfactory. They clearly show that the degree of connection significantly affects the forces brought about by the combined action of concrete shrinkage and temperature.

Conclusion: The results of the present approach and those of the existing model developed by Rahal et al are in good agreement. They clearly show the effect of concrete shrinkage and temperature as a function of the connection degree N/Nf on the behavior of composite steel-concrete beams.

Introduction/purpose: Wheeled armored combat vehicles are combat systems that are increasingly present in modern armed conflicts, especially in operations against asymmetric threats. The global wheeled armored vehicle market is constantly growing, which reflects their application in a wide range of missions and tasks of armed forces. The existence of numerous models of these vehicles with different technical and exploitation characteristics, along with the possibility of adaptation to specific needs, further complicates the choice of the most suitable alternative. The paper presents the case of solving the problem of selecting the most suitable multi-purpose medium-class wheeled armored vehicle with a 4x4 drive formula when choosing one of the four alternatives, using individual and group multi-criteria decision-making methods.

Methods: In the paper, the methods of multi-criteria decision making were applied to solve problems in the field of complex combat systems selection. Experts from the field of tactics with weapon systems have ranked the alternatives following the defined criteria using the AHP (Analytic Hierarchy Process) and the PROMETHEE II (Preference Ranking Organization Method for Enrichment Evaluations II) methods. The results obtained by individual decision making were subjected to the Condorcet method of group decision making to make a final decision.

Result: Selection of the most suitable vehicle by the defined criteria.

Conclusion: Solving the problem involves taking into account the views of military experts regarding the optimization of multiple criteria to provide the best performance vehicle suitable for use in various missions. The choice of a multi-purpose wheeled armored combat vehicle is a complex process influenced by numerous factors that cannot be analyzed objectively without the application of adequate mathematical models.

Introduction/purpose: The study of the theory of fuzzy sets was prompted by the presence of uncertainty as an essential part of real-world problems, leading Zadeh to address the problem of indeterminacy. The notion of fuzzy logic was introduced by Zadeh. Unlike traditional logic theory, where an element either belongs to the set or does not, in fuzzy logic, the affiliation of the element to the set is expressed as a number from the interval [0, 1].

Methods: The theory of a fixed point in fuzzy metric spaces can be viewed in different ways, one of which involves the use of fuzzy logic. Fuzzy metric spaces, which are specific types of topological spaces with pleasing ”geometric” characteristics, possess a number of appealing properties and are commonly used in both pure and applied sciences. Metric spaces and their various generalizations frequently occur in computer science applications. For this reason, a new space called a Pompeiu-Hausdorff fuzzy b-metric space is constructed in this paper. Results: In this space, some new fixed point results are also formulated and proven. Additionally, a general common fixed point theorem for a pair of multi-valued mappings in Pompeiu-Hausdorff fuzzy b-metric spaces is investigated. The findings obtained in fuzzy metric spaces, such as those discussed in the article of Shen, Y. et al. (2012. Fixed point theorems in fuzzy metric spaces. Applied Mathematics Letters, 25, pp.138-141), are generalized by the results in this paper, and additional specific findings are produced and supported by examples.

Conclusions: The study of denotational semantics and their applications in control theory using fuzzy b-metric spaces and Pompeiu-Hausdorff fuzzy b-metric spaces will be an important next step.