Antal Bakonyi

59394734000

Publications - 7

In Silico Benchmarking of Fatigue Life Estimation Models for Passive SMD Solder Joints Under Thermal Cycling

Ambrus Zelei Gusztáv Fekete Antal Bakonyi

Publication Name: Applied Mechanics

Publication Date: 2024-12-01

Volume: 5

Issue: 4

Page Range: 877-907

Description:

Related to microelectronics’ reliability, lifetime estimation methods have gained importance, especially for surface-mounted devices. The virtual testing of electronic assemblies necessitates the geometry modeling and finite element analysis of the solder joint. The effect of the simplification of the solder geometry on the predicted lifetime is an open question. Furthermore, there is still not yet straightforward guidance for the choice of the material model and fatigue lifetime model. In this study, the impact of the geometry input method, the material model and the lifetime model choice is investigated on two different surface-mounted capacitors in a simulation-based benchmark analysis under thermal cyclic loading. Four different types of solder geometry modeling approaches are compared, among which one is a physics-based approach. Ten different fatigue models founded on plastic and viscoplastic material models are benchmarked. The results show that the component standoff height and the solder volume have a positive effect on the lifetime, while the capacitor size has a slightly negative effect on the lifetime. The results also suggest that approximate geometries can be used to replace the physics-based model with a restriction for the minimum standoff height.

Open Access: Yes

DOI: 10.3390/applmech5040049

Benchmark Analysis of Plastic Strain-Based Lifetime Estimation Fatigue Models in Aspect of SMD Component Standoff Height

Ambrus Zelei Antal Bakonyi

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 128-134

Description:

Thermomechanical fatigue is one of the most common cause of the failure in microelectronic technology in the solder joints. The lifetime prediction for microelectronic components is a very important area in nowadays automotive industry, because the lifetime estimation fatigue models in the literature differ in their results by orders of magnitude. However, developing an accurate lifetime estimation methodology for microelectronic components is not straightforward, because the failure mechanism of the solder joints under cyclic thermomechanical load is not fully understood. In addition, there are numerous tolerances and uncertainties during the designing and manufacturing processes, such as component size, copper pad area, solder material volume or the formed standoff height of the component from the copper pad. These parameters can hugely affect the lifetime of the solder joint. In this paper a benchmark analysis based on finite element method were carried out with four plastic strain-based fatigue models to understand the impact of the standoff height to the estimated lifetimes. Three CAD models were created with identical parameters, except the standoff height of the components. Creating the solder geometries for the 3D models, Surface Evolver software were used. The result shows that the fatigue models give the same tendencies varying the standoff height values. However, changing the standoff height increases the differences between models, even if they are tuned so that the estimated lifetime matches for a certain standoff height.

Open Access: Yes

DOI: 10.3233/ATDE240536

Energy-Based Approach on Calculating Stand-Off Height of Different Solder Joints

Ambrus Zelei Antal Bakonyi

Publication Name: 2024 IEEE 10th Electronics System Integration Technology Conference Estc 2024 Proceedings

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In the lifetime prediction simulations of microelectronics solder joints, the stand-off height and misalignment parameters are founded on a variety of estimation methods from very simple to complex approaches. However, the stand-off height and misalignment play essential role in the lifetime of solder joints. Thus, a reliable lifetime simulation requires proper solder geometry model. Many researchers calculate the solder geometry with the software called Surface Evolver, which minimizes the total energy, including the surface tension energy. Some of these studies used energy-based methods for the stand-off height prediction. The first hypothesis is that by changing the predefined value of stand-off height in the Surface Evolver simulation, we gain different total energy values and by differentiating the energy with respect to the stand-off height, we can obtain the vertical force and a nonlinear spring characteristic for the molten solder. Similar results can be found in the literature for BGA. Secondly, it is hypothesized that this spring-like behaviour is observable in horizontal direction too, which is related with the misalignment of the component. The presented approach provides a simple model for the prediction of the stand-off height and misalignment.

Open Access: Yes

DOI: 10.1109/ESTC60143.2024.10712056

Sustainable Water and Energy Management Through a Solar-Hydrodynamic System in a Lake Velence Settlement, Hungary

Katalin Bene Attila Kálmán Antal Bakonyi Richard P. Ray

Publication Name: Infrastructures

Publication Date: 2025-10-01

Volume: 10

Issue: 10

Page Range: Unknown

Description:

The Lake Velence watershed faces increasing challenges driven by local and global factors, including the impacts of climate change, energy resource limitations, and greenhouse gas emissions. These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns. Such dynamics strain the region’s scarce water resources, negatively affecting the environment, tourism, recreation, agriculture, and economic prospects. Nadap, a hilly settlement within the watershed, experiences frequent flooding and poor water retention, yet it also boasts the highest solar panel capacity per property in Hungary. This research addresses these interconnected challenges by designing a solar-hydrodynamic network comprising four multi-purpose water reservoirs. By leveraging the settlement’s solar capacity and geographical features, the reservoirs provide numerous benefits to local stakeholders and extend their impact far beyond their borders. These include stormwater management with flash flood mitigation, seasonal green energy storage, water security for agriculture and irrigation, wildlife conservation, recreational opportunities, carbon-smart winery developments, and the creation of sustainable blue-green settlements. Reservoir locations and dimensions were determined by analyzing geographical characteristics, stormwater volume, energy demand, solar panel performance, and rainfall data. The hydrodynamic system, modeled in Matlab, was optimized to ensure efficient water usage for irrigation, animal hydration, and other needs while minimizing evaporation losses and carbon emissions. This research presents a design framework for low-carbon and cost-effective solutions that address water management and energy storage, promoting environmental, social, and economic sustainability. The multi-purpose use of retained rainwater solves various existing problems/challenges, strengthens a community’s self-sustainability, and fosters regional growth. This integrated approach can serve as a model for other municipalities and for developing cost-effective inter-settlement and cross-catchment solutions, with a short payback period, facing similar challenges.

Open Access: Yes

DOI: 10.3390/infrastructures10100275

Data-driven lifetime estimation of solder joints with various geometries

Ambrus Zelei Antal Bakonyi Zoltan Safar

Publication Name: Pollack Periodica

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Virtual lifetime estimation of microelectronic devices has become essential, due to the tightening requirements and the trend of electronification. Thermal cycling load cause fatigue crack in solder joints and therefore functional failures. The application of the fatigue models viable in the literature is circumstantial for industrial scale problems. The exploitation of the already existing simulation data in data-driven models is a promising solution for speeding up the virtual lifetime estimation process. This paper benchmarks data-driven methods to predict the lifetime of solder joints with different geometric properties using a dataset originated from finite element simulation results. This case study shows that the nonlinear function fitting and the neural network are applicable.

Open Access: Yes

DOI: 10.1556/606.2025.01301

Finite Element Simulation of Surface-Mount Resistor Solder Joint Quarter Models Under Thermomechanical Loading †

Antal Bakonyi Norbert Kiss Dániel Székely Matthew Joshua Sandy Yashveer Dunputh Mahmud M.D. Firoz

Publication Name: Engineering Proceedings

Publication Date: 2025-01-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

Virtual lifetime estimation is growing in importance, as replacing physical tests by simulations leads to cost reductions in the development of microelectronics assemblies. However, the predictions made by fatigue models often differ significantly from the lifetimes recorded in physical tests. Tuning these models is not straightforward, and results are often accurate only in specific test cases. Deviations may arise from manufacturing tolerances in the soldering process which can lead to deviations in the solder joint geometry. These include variations in the size of the copper pad area or in the volume of solder material. These factors, which have impacts on estimated lifetimes, are not fully understood. This paper assesses the impact of solder geometry in parallel with that of thermal cycling properties on estimated lifetimes. It is demonstrated that the shape and thermocycling properties of the solder joint significantly affect the thermomechanical lifetimes of surface-mounted resistors.

Open Access: Yes

DOI: 10.3390/engproc2025113050

Sensitivity Analysis of SAC 305 Solder Polycrystal Mechanical Parameters and Predicted Fatigue Lifetime with Different Grain Structures

Ambrus Zelei Antal Bakonyi Levente Bodnár

Publication Name: Applied Sciences Switzerland

Publication Date: 2026-01-01

Volume: 16

Issue: 2

Page Range: Unknown

Description:

The microstructural behaviours of solder joints during thermomechanical stresses are still not fully understood, and the thermomechanical reliability of solder joints remains a research area for scientists. In many cases, the solder material is modelled as a homogeneous material in Finite Element-based lifetime estimation calculations, while the microstructural effects are neglected. The development of virtual lifetime estimation methods is required; these methods should involve grain structure and therefore provide accurate results for a variety of test cases under thermomechanical loading. This paper presents a meso-scale analysis of lead-free SAC305 solder polycrystals using DAMASK modelling of the grain structure of the solder material and emulating mechanical loading while investigating the mechanical response of the polycrystal. Our finding is that the orientations and grain sizes of the solder polycrystal have significant effects on the mechanical parameters, and these microstructural parameters could not be neglected, because the impact of these also has a very relevant impact on the estimated lifetimes.

Open Access: Yes

DOI: 10.3390/app16020704