Péter Grubits

58853840100

Publications - 11

Automated elasto-plastic design of truss structures based on residual plastic deformations using a geometrical nonlinear optimization framework

Majid Movahedi Rad Péter Grubits

Publication Name: Computers and Structures

Publication Date: 2025-09-01

Volume: 316

Issue: Unknown

Page Range: Unknown

Description:

This paper introduces a novel automated framework for the optimal design of steel truss structures, incorporating plastic deformations through the complementary strain energy of residual forces while minimizing weight. The presented methodology is equally applicable to purely elastic scenarios, ensuring zero plastic deformations and further reducing material usage. To achieve this, a nonlinear finite element (FE) program was developed, capable of accounting for large deformations and initial geometric imperfections. A genetic algorithm (GA) was integrated to iteratively optimize the objective function, enabling a fully automated design process. The efficiency and versatility of the framework were validated through four numerical examples. The first two comprise benchmark cases: a 9-bar planar truss and a 25-bar space truss. The remaining two examples were selected to be more representative of practical applications, involving a prestressed arched truss and a double-layer space truss. Analyses of various configurations were performed to demonstrate the robustness of the approach. Using the proposed methodology, significant improvements in plastic performance and material efficiency were achieved, underscoring its potential, adaptability, and effectiveness in advancing truss design techniques.

Open Access: Yes

DOI: 10.1016/j.compstruc.2025.107855

A Nonlinear Computational Framework for Optimizing Steel End-Plate Connections Using the Finite Element Method and Genetic Algorithms

Majid Movahedi Rad Péter Grubits Tamás Balogh

Publication Name: Algorithms

Publication Date: 2025-08-01

Volume: 18

Issue: 8

Page Range: Unknown

Description:

The design of steel connections presents considerable complexity due to their inherently nonlinear behavior, cost constraints, and the necessity to comply with structural design codes. These factors highlight the need for advanced computational algorithms to identify optimal solutions. In this study, a comprehensive computational framework is presented in which the finite element method (FEM) is integrated with a genetic algorithm (GA) to optimize material usage in bolted steel end-plate joints, while structural safety is ensured based on multiple performance criteria. By incorporating both material and geometric nonlinearities, the mechanical response of the connections is accurately captured. The proposed approach is applied to a representative beam-to-column assembly, with numerical results verified against experimental data. By employing the framework, an optimized layout is obtained, yielding a (Formula presented.) improvement in the overall performance objective compared to the best-performing validated model and a (Formula presented.) reduction in material volume relative to the most efficient feasible alternative. Furthermore, a (Formula presented.) decrease in equivalent plastic strain is achieved compared to the configuration exhibiting the highest level of inelastic deformation. These findings demonstrate that the developed method is capable of enhancing design efficiency and precision, underscoring the potential of advanced computational tools in structural engineering applications.

Open Access: Yes

DOI: 10.3390/a18080460

Script-Based Material and Geometrical Modeling of Steel–Concrete Composite Connections for Comprehensive Analysis Under Varied Configurations

János Szép Majid Movahedi Rad Daniel Gosztola Péter Grubits

Publication Name: Applied Sciences Switzerland

Publication Date: 2025-03-01

Volume: 15

Issue: 6

Page Range: Unknown

Description:

The behavior of steel–concrete composite structures is significantly influenced by the efficiency of the shear connections that link the two materials. This research examines the performance of stud shear connectors, with an emphasis on analyzing the effect of different geometric design parameters. A computational model was created utilizing Python 3.13 to enable thorough digital monitoring of the influence of these parameters on the structural performance of composite connections. Developed within the ABAQUS framework, the model integrates geometric nonlinearity and the Concrete Damage Plasticity (CDP) approach to achieve detailed simulation of structural behavior. Essential design aspects, including stud diameter, stud height, head dimensions, and spacing in both longitudinal and transverse directions, were analyzed. The Python-based parametric model allows for easy modification of design parameters, ensuring efficiency and minimizing modeling errors. The significance of stud diameter changes was analyzed in accordance with Eurocode standards and previous studies. It was found that stud length has a reduced effect on structural performance, particularly when considering the concrete properties used in bridge construction, where compressive failure of the concrete zone is more critical at lower concrete strengths. Additional factors, such as stud head dimensions, were investigated but were found to have minimal effect on the behavior of steel–concrete composite connections. Longitudinal stud spacing emerged as a critical factor influencing structural performance, with optimal results achieved at a spacing of 13d. Spacings of 2d, 3d, and 4d demonstrated overlapping effects, leading to significant performance reductions, as indicated by comparisons of ultimate load and force–displacement responses. For transverse spacing, closer stud arrangements proved effective in reducing the likelihood of slip at the steel–concrete interface, enhancing composite action, and lowering stress concentrations. Additionally, reducing the transverse distance between studs allowed for the use of more shear connectors, increasing redundancy and enhancing performance, especially with grouped-stud connectors (GSCs).

Open Access: Yes

DOI: 10.3390/app15063095

Optimization of Bolted Steel T-Stub Connection Based on Nonlinear Finite Element Analysis Using Genetic Algorithm

Majid Movahedi Rad Péter Grubits Tamás Balogh

Publication Name: Infrastructures

Publication Date: 2025-01-01

Volume: 10

Issue: 1

Page Range: Unknown

Description:

The equivalent T-stub method is frequently employed in infrastructure projects, including bridge engineering, to simplify bolted connection analysis. However, steel connections remain inherently complex due to nonlinear behavior, cost considerations, and code compliance, framing the design process as a discrete structural optimization problem. This research addresses these challenges by presenting a comprehensive calculation framework that combines the finite element method (FEM) and genetic algorithm (GA) to accurately evaluate the structural performance of bolted T-stub configurations. The proposed approach accounts for nonlinear behavior, thereby reflecting realistic structural responses. To enhance the simulation efficiency and reduce the computational time without significantly compromising accuracy, the study introduces a simplified modeling methodology. The effectiveness of the approach is demonstrated through the development and experimental validation of a selected T-stub connection. Furthermore, a parameter sensitivity analysis is conducted to showcase the range of possible outcomes, emphasizing the potential for optimization. Finally, the proposed connections were optimized using GA, highlighting the benefits of structural optimization in achieving efficient and precise designs for steel connections.

Open Access: Yes

DOI: 10.3390/infrastructures10010008

Structural topology optimization for plastic-limit behavior of I-beams, considering various beam-column connections

Marco Domaneschi Peyman Aela Majid Movahedi Rad Raffaele Cucuzza Muayad Habashneh Péter Grubits

Publication Name: Mechanics Based Design of Structures and Machines

Publication Date: 2025-01-01

Volume: 53

Issue: 4

Page Range: 2719-2743

Description:

This work proposes topology optimization for steel I-beams, including consideration of bolted beam-column connections with geometric and material nonlinear analysis. The aim is to assess and compare the topological configurations influenced by different connections, examining their stress distribution and rotational stiffness to illustrate the potential of structural optimization. The bi-directional evolutionary structural optimization (BESO) approach is implemented. Furthermore, several bolted steel beam-column configurations were validated based on experimental tests. Subsequently, a series of finite element models were developed, contributing to a comprehensive understanding of the plastic-limit behavior of I-beams under different loading conditions. The proposed method could potentially use a lesser quantity of material while maintaining the same level of structural performance. The results indicate that the implementation of structural topology optimization on I-beams while considering various beam-column connections, yields structural performance similar to that of solid web configurations, achieved through material reduction.

Open Access: Yes

DOI: 10.1080/15397734.2024.2412757

Advanced Numerical Simulation and Modeling of Multi-Pass Welding Processes: Detailed Analysis of Temperature Distribution in Structural Elements

János Szép Majid Movahedi Rad Daniel Gosztola Péter Grubits

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 823-828

Description:

The growing importance of numerical simulations in the welding industry stems from their ability to enhance structural performance and sustainability by ensuring optimal manufacturing conditions. The use of the finite element method (FEM) allows for detailed and precise calculations of the mechanical and material changes caused by the welding process. Acquiring knowledge of these parameters not only serves to augment the quality of the manufacturing process but also yields consequential benefits, such as reducing adverse effects. Consequently, the enhancement of structural performance and prolonged lifespan becomes achievable, aligning with overarching sustainability goals. To achieve this goal, this paper utilizes numerical simulations of welding processes based on experimental tests, with a specific focus on analyzing temperatures generated within the structures. In the finite element analysis (FEA), a total of 12 welding cycles were systematically modeled to align with experimental conditions, incorporating cooling intervals, preheating considerations, and the relevant section of the connecting concrete structure with studs. The outcomes of this research exemplify the potential of numerical simulation in the welding industry, demonstrating a diverse range of results achieved through FEA to enhance the quality of structures within the context of sustainability.

Open Access: Yes

DOI: 10.3303/CET24114138

Numerical Modeling of Multi-Pass Arc Welding Processes: Integration with Experimental Validation for Distortion analysis and Characterization

János Szép Marco Domaneschi Majid Movahedi Rad Raffaele Cucuzza Daniel Gosztola Péter Grubits

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 248-254

Description:

The increasing significance of numerical simulations in the welding industry arises from their capacity to improve manufacturing conditions, ensuring greater effectiveness and precision. The utilization of the finite element method (FEM) enables comprehensive and focused calculations of mechanical and material structural alterations induced by the welding process. Acquiring knowledge of these parameters not only serves to augment the quality of the manufacturing process but also yields consequential benefits, such as reducing adverse effects like base plate distortion. Consequently, enhancing structural performance and prolonging lifespan becomes achievable, aligning with overarching sustainability goals. To accomplish this objective, this paper involves the numerical simulation of a welding process based on experimental tests, with a focus on investigating the deformations caused by the heat generated during welding as the primary parameter of interest. Advanced modeling techniques are employed to assess the results as part of a comprehensive thermo-mechanical analysis framework, examining and characterizing the impact of the temperature distribution. In the finite element analysis (FEA), a total of 12 welding cycles were systematically modeled to align with experimental conditions, incorporating cooling intervals and preheating considerations. The outcomes of this research exemplify the potential of numerical simulation in the welding industry, demonstrating a diverse range of results achieved through FEA to enhance the quality of structures.

Open Access: Yes

DOI: 10.3233/ATDE240552

Advanced Numerical Simulation and Modeling of Welding Processes: Stochastic representation of parameters for Improved Fabrication

János Szép Majid Movahedi Rad Muayad Habashneh Daniel Gosztola Péter Grubits

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 619-624

Description:

Numerical simulations play a pivotal role in advancing fabrication processes and welding technologies, enabling the pursuit of sustainable practices. By employing the finite element method, crucial insights regarding welded specimens can be derived, encompassing deformed shapes, residual stresses, and even microstructural properties such as phase proportions and hardness. This study focuses on the modeling framework of welding processes, emphasizing the influence of various welding parameters on sustainable outcomes, including reduced environmental impact and enhanced resource efficiency. The investigation delves into the characterization of heat sources, accounting for temperature-dependent material properties and developing a comprehensive thermo-mechanical analysis. By incorporating sustainability considerations and utilizing our Finite Element (FE) model, we conducted further analysis to elucidate the stability behavior, aligning with sustainable objectives. By considering welding current, arc voltage, and welding speed as random variables with mean values and standard deviations, the study aims to identify a model that effectively accounts for the inherent randomness of the welding process. This research contributes to the growing body of knowledge on sustainable welding practices by merging numerical simulations, advanced modeling techniques, and sustainability principles. The outcomes of this study have the potential to inform industry stakeholders and decision-makers about the most effective strategies for achieving sustainable welding processes and minimizing the ecological footprint of the welding operations.

Open Access: Yes

DOI: 10.3303/CET23107104

Elasto-plastic truss optimization under geometric nonlinearity using a genetic algorithm

Pálma Porrogi Majid Movahedi Rad Péter Grubits

Publication Name: Fracture and Structural Integrity

Publication Date: 2026-01-01

Volume: 20

Issue: 75

Page Range: 124-156

Description:

No description provided

Open Access: Yes

DOI: 10.3221/IGF-ESIS.75.10

Sustainable Design of Steel Frames Based on Topological Optimization Considering Geometrical and Material Nonlinearities

Marco Domaneschi Majid Movahedi Rad Raffaele Cucuzza Muayad Habashneh Péter Grubits

Publication Name: Lecture Notes in Civil Engineering

Publication Date: 2025-01-01

Volume: 770 LNCE

Issue: Unknown

Page Range: 204-213

Description:

This research introduces a sustainable approach to designing steel frames, specifically focusing on the topological optimization of I-beam webs. The proposed methodology incorporates the plastic behavior of structural steel and considers geometric nonlinearity. The primary objective of the study is to provide an environmentally sustainable design that achieves maximum material efficiency. To accomplish this goal, the bi-directional evolutionary structural optimization (BESO) approach is employed. Four different beam-column setups, each featuring various beam web formations, were validated according to previous experimental tests. Based on the results, topology optimization was conducted, considering the volume fraction corresponding to the different web openings. Subsequently, the structural behavior in terms of stress intensity of the optimized and conventional configurations was compared. Subsequently, during the final stage, the volume fraction was reduced to 60%, and the performance of the resulting setup was examined. The results of this research demonstrate the efficiency of topology optimization and suggest that this technique has the potential to reduce the material quantity required for producing steel structures while achieving better performance in terms of stress levels, thus providing an environmentally sustainable design.

Open Access: Yes

DOI: 10.1007/978-3-032-08407-1_18

GENETIC ALGORITHM-BASED OPTIMIZATION OF BOLTED T-STUB CONNECTION UNDER DYNAMIC LOADING USING FINITE ELEMENT ANALYSIS

Ákos Wolf Majid Movahedi Rad Péter Grubits Majid Movahedi Rad

Publication Name: Compdyn Proceedings

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: 3413-3423

Description:

The equivalent T-stub technique is widely utilized as a design solution for steel bolted connections, which are otherwise complex to analyze. However, traditional standard-based methods often lack the precision required for accurate analysis, particularly when accounting for dynamic effects, such as those caused by earthquakes, leading to designs that may not be sustainable. This research addresses this issue by introducing a framework aimed at optimizing the bolt layout in a selected T-stub connection to maximize structural performance under cyclic loading, thereby enhancing sustainability. The finite element method (FEM) was employed to account for nonlinear characteristics, including the elastic-plastic behavior of steel, large deformations, and contact nonlinearities, ensuring precise analysis. The developed T-stub model was validated against experimental tests to reflect real-world behavior, utilizing ABAQUS finite element software. Optimization was conducted using a genetic algorithm (GA) implemented in the PYTHON programming language, linked to the simulation process. The results demonstrate the effectiveness of the proposed framework in significantly enhancing the structural performance of the steel T-stub connection under cyclic loading conditions without requiring additional material, thereby contributing to a more sustainable design.

Open Access: Yes

DOI: 10.7712/120125.12662.25059