http://hdl.handle.net/123456789/172 Tue, 02 Jun 2026 05:31:20 GMT 2026-06-02T05:31:20Z http://hdl.handle.net/123456789/224197 Title: Low-Computational-Cost Technique for Modeling Macro Fiber Composite Piezoelectric Actuators Using Finite Element Method Authors: Mohamed A. Fanni; Abdelfatah M. Mohamed; Shigeo Yoshida; Mohamed, Diaa Abstract: The large number of interdigitated electrodes (IDEs) in a macro fiber composite (MFC) piezoelectric actuator dictates using a very fine finite element (FE) mesh that requires extremely large computational costs, especially with a large number of actuators. The situation becomes infeasible if repeated finite element simulations are required, as in control tasks. In this paper, an efficient technique is proposed for modeling MFC using a finite element method. The proposed technique replaces the MFC actuator with an equivalent simple monolithic piezoceramic actuator using two electrodes only, which dramatically reduces the computational costs. The proposed technique was proven theoretically since it generates the same electric field, strain, and displacement as the physical MFC. Then, it was validated with the detailed FE model using the actual number of IDEs, as well as with experimental tests using triaxial rosette strain gauges. The computational costs for the simplified model compared with the detailed model were dramatically reduced by about 74% for memory usage, 99% for result file size, and 98.6% for computational time. Furthermore, the experimental results successfully verified the proposed technique with good consistency. To show the effectiveness of the proposed technique, it was used to simulate a morphing wing covered almost entirely by MFCs with low computational cost. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/123456789/224197 2021-01-01T00:00:00Z http://hdl.handle.net/123456789/224194 Title: Trajectory tracking control of autonomous underwater vehicles: a review from classical methods to AI-based approaches Authors: Eissa, Aly M.; Mohamed, Samer A.; Awad, Mohammed Ibrahim; Abd El Munim, Hossam E.; Mohamed, Diaa Abstract: Autonomous Underwater Vehicles (AUVs) are essential for applications such as seabed mapping, environmental monitoring, offshore infrastructure inspection, and search-and-rescue operations. However, achieving accurate trajectory tracking remains a fundamental challenge due to nonlinear and strongly coupled six-degree-of-freedom dynamics, hydrodynamic parameter uncertainties, environmental disturbances, and limitations introduced by sensor noise, actuator faults, and imperfect modeling of added mass, damping, and Coriolis–centripetal forces.Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, this review systematically classifies trajectory-tracking control strategies for AUVs into three main categories. (i) Classical controllers, including PID and Sliding Mode Control (SMC), are analyzed for their simplicity, robustness, and ease of implementation. (ii) Intelligent controllers, such as Fuzzy Logic Control (FLC), Reinforcement Learning (RL), and Physics-Informed Neural Networks (PINNs), are reviewed for their adaptability, learning capabilities, and effectiveness in handling nonlinearities and time-varying disturbances, while addressing challenges related to data availability and computational cost. (iii) Hybrid approaches, including Adaptive Neuro-Fuzzy Inference Systems (ANFIS), Physics-Informed Reinforcement Learning (PI-RL), Fault-Tolerant Control (FTC), and Sim-to-Real Transfer (SRT) techniques, are examined for their ability to integrate model-based reliability with data-driven adaptability and improve resilience under uncertainties, noise, and faults.Classical controllers provide structural simplicity and robustness but suffer reduced accuracy in highly nonlinear and noisy environments. Intelligent methods like RL and PINNs improve adaptability and reduce tracking errors but demand extensive data and computational resources. Hybrid approaches, particularly ANFIS and PI-RL, achieve high tracking accuracy and maintain robust performance under various uncertainties. Sim-to-Real Transfer (SRT) techniques further enhance real-world deployment. A meta-analysis of 120 peer-reviewed studies quantifies performance trends in terms of root-mean-square error (RMSE), settling time, robustness, and computational cost. The review highlights future research opportunities in domain randomization, adaptive fault-tolerant control, and physics-guided hybrid learning to enable reliable real-world AUV operations. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/123456789/224194 2026-01-01T00:00:00Z http://hdl.handle.net/123456789/221683 Title: Experimentally investigating the structural capacity of slender web tapered built up plate girder with web opening Authors: Ebid, Ahmed M; Ibrahim, Sherif M.; El-Aghoury, Mohamed A; Taher, Mohamed Abstract: Built-up plate girders are widely used in structural applications where hot-rolled beams may not provide sufficient strength or stiffness. To achieve a cost-effective design, tapered plate girders are often employed, allowing for an optimized distribution of material by gradually varying the web depth along the span. In many practical applications, web openings are introduced to accommodate service ducts, utilities, and weight reduction, making them an essential feature in modern steel structures. However, while design codes provide well-established methods for prismatic girders, the web behavior of tapered girders with web openings remains insufficiently investigated, leading to gaps in existing predictive models. This research presents a novel equation to estimate the web capacity of tapered plate girders with web opening, considering parameters such as the panel aspect ratio, web opening size to panel average height ratio and tapering ratio. The equation was validated with the experimental results giving a maximum error of 8%. A comparative study was conducted using different methodologies of steel design standards and previous researches to evaluate their results with the experiments. The results of these methodologies demonstrated significant contradictions. Where some standards underestimated the web capacity by up to 58% while some others overestimated it by up to 45%. The presented formula gives significant improvement in designing the steel plate girders with web opening, hence in structural design. Future research may consider enhancing the equation taking into consideration widening the range of values for taken parameters or by considering more parameters regarding the girders' geometry, loading and boundary conditions. Thu, 31 Jul 2025 00:00:00 GMT http://hdl.handle.net/123456789/221683 2025-07-31T00:00:00Z http://hdl.handle.net/123456789/221682 Title: Experimental and numerical investigation of cold-formed sigma sections subjected to bending and torsion moments Authors: Ismail, Mohamed; Hammad, Ali; Ibrahim, Sherif M. Abstract: Cold-Formed Steel (CFS) has gained prominence in the construction industry due to its sustainability and cost-effectiveness. This paper explores the behavior of CFS sigma beams, a monosymmetric profile that deviates from lipped C-sections by incorporating web stiffening to enhance structural efficiency in their applications as flexural members. The beams' behavior is experimentally investigated under eccentric loading, caused by load application offset from the cross-section shear center, combining bending and torsional moments. A total of 24 experimental tests were conducted on simply supported sigma beams with various profiles subjected to eccentric load at mid-span, varying both the thickness and the loading eccentricity. The test setup was designed to induce the required loading and end conditions. These tests were then utilized in the construction of numerical models using Abaqus non-linear finite element analysis (FEA). The numerical models were validated against the experimental test results, showing good agreement in terms of ultimate strength, lateral deformations, and failure modes. Finally, a comparative analysis was conducted comparing the experimental outcomes and the GB 50018-2002 for bending and torsion. The comparison showed that the current code underestimates the sectional capacity by 67 % on average. A modified design equation is proposed to predict the sigma sections subjected to both bending moment and torsion. The proposed equation improved the accuracy significantly, with only 13 % lower estimation on average. Mon, 01 Sep 2025 00:00:00 GMT http://hdl.handle.net/123456789/221682 2025-09-01T00:00:00Z