http://hdl.handle.net/20.500.14044/33792 2026-07-26T13:38:18Z 2026-07-26T13:38:18Z Todor, Mihai-Paul Kiss, Imre Bulei, Ciprian http://hdl.handle.net/20.500.14044/32119 2025-09-17T08:30:13Z 2025-01-01T00:00:00Z

Design and Realization of a Compression Molding Press, used to Produce Plate Composite Parts Todor, Mihai-Paul; Kiss, Imre; Bulei, Ciprian Nowadays, there is a need to use material resources that incorporate low manufacturing, processing and exploitation costs. Thus, the existence and accessibility on the market of materials with increasing mechanical performance and with the lowest densities possible, under conditions of acceptable production and operating costs, is taken into account. Composite materials arouse a growing interest from many industrial sectors, and their use tends to generalize. For design, the emergence of these new materials represents a major change, which has a profound impact in the design and realization of industrial products. In the same time, compression molding is a high–volume, high– pressure method suitable for molding fiber or fabric reinforcements – unidirectional tapes, woven fabrics, randomly oriented fiber mat or chopped strand – into a polymer matrix material. We’ll show how anyone can use this process to create plate composite prototypes using an original designed compression molding press, realized within the Faculty’s Composite & Advanced Materials Laboratory, used to produce plate composite parts with post–consumer waste textile inserts.

2025-01-01T00:00:00Z Slimane, Sayah Mouhoub, Birane Khalil, Benmouiza http://hdl.handle.net/20.500.14044/32117 2025-09-17T08:29:59Z 2025-01-01T00:00:00Z

Deep Learning-based Control Perspective for Single-Phase Grid-connected Inverter Using Gated Recurrent Units Slimane, Sayah; Mouhoub, Birane; Khalil, Benmouiza This paper introduces a novel approach to control single-phase grid-connected inverters (GCIs) using artificial intelligence (AI), specifically employing a deep learning- based method with Gated Recurrent Unit (GRU) networks. The proposed GRU-based controller is trained offline using TensorFlow and Keras libraries in Python, and is subsequently implemented for real-time applications. Comparative analysis between the GRU-based controller and the conventional PI controller reveals distinct advantages of the former, including improved transient response and reduced oscillations. Furthermore, the GRU-based controller demonstrates superior performance, reducing the total harmonic distortion (THD) and efficiently regulating current in the presence of varying grid conditions.

2025-01-01T00:00:00Z Kostić, Sonja Tadić, Danijela Miljojković, Jasmina Kočović, Vladimir Komatina, Nikola Jovanović, Saša http://hdl.handle.net/20.500.14044/32115 2025-09-17T08:29:45Z 2025-01-01T00:00:00Z

Evaluation and Selection of Design Solutions for a Small Laboratory Tensile Testing Device under a Type 2 Fuzzy Environment Kostić, Sonja; Tadić, Danijela; Miljojković, Jasmina; Kočović, Vladimir; Komatina, Nikola; Jovanović, Saša In this research, evaluating and selecting design solutions for a small laboratory tensile testing device is stated as a multi-criteria, decision analysis problem, incorporating both quantitative and qualitative criteria. Fuzzy ratings of criteria values are provided by managers, students, and potential customers. Their assessments are described using linguistic expressions modelled by type 2 triangular fuzzy numbers. The ranking of various design solutions for the small laboratory tensile testing devices is carried out by applying the proposed two-stage fuzzy model. In the first stage, the weight vector is calculated by using Criteria Importance Through Intercriteria Correlation, which is extended with type 2 triangular fuzzy numbers. The ranking of small laboratory tensile testing device design solutions is obtained by applying the proposed Technique for Order Preference by Similarity to Ideal Solution with type 2 triangular fuzzy numbers. The proposed two-stage fuzzy model is tested on real-life data, originating from an industrial company, operating in the Republic of Serbia. By applying the proposed methodology, the best design solutions for the small laboratory tensile testing devices are selected in an exact manner. This solution is less burdened by subjective decision-makers' opinions, making it more accurate. In this way, the risk of diversification is reduced, while simultaneously enhancing the competitiveness and sustainability of the business in the long run.

2025-01-01T00:00:00Z Wang, Zhiqiang Lei, Zhenyu http://hdl.handle.net/20.500.14044/32113 2025-09-17T08:29:25Z 2025-01-01T00:00:00Z

Mechanism Analysis and Behavior Characterization of Stick-Slip Vibration Wang, Zhiqiang; Lei, Zhenyu In order to clarify stick-slip vibration mechanisms and characterize stick-slip vibration behaviors, a three-dimensional numerical model of the slider-plate friction contact was established using the finite element method, and the mechanism characteristics of slip vibration and stick-slip vibration were analyzed in terms of contact stick-slip and vibration responses. Meanwhile, the stick-slip vibration behaviors of the system under the influence of different parameters were investigated. The results show that depending on the vibration form of the system, the distribution and amplitude of contact stresses in adhesion and slip states differ. The frequency domain curve of the friction force for the slip vibration mainly includes three characteristic frequency ranges, namely, 0~75 Hz, 80~150 Hz and 1300~1600 Hz, while the characteristic frequency component of the friction force for the stick-slip vibration mainly exhibits 0~65 Hz. Therefore, the high-frequency component of the friction force may originate from the continuous slip vibration. The presence and monotonically increasing (or constant) of the relative velocity at the contact interface drives the formation of the slip vibration, while the presence of non-monotonically varying relative velocity drives the formation of the stick-slip vibration. Appropriate reductions in spring stiffness and plate motion velocity and increases in the damper damping will slow down the degree of stick-slip vibration, thereby reducing the effect of stick-slip vibration on the system behavior. In addition, compared to the constant value friction characteristic of the contact interface, the exponential decay friction characteristic has a smaller effect on the degree of stick-slip vibration of the system.

2025-01-01T00:00:00Z