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Item type:Publication, Access status: without files , Structural integrity of designed sandwich panels under low temperature conditions: blast effect assessment using finite element simulation(Springer, 2025-11-25); ; ; This research employs a detailed finite element analysis to investigate the blast resilience of metallic sandwich panels under various thermal and structural conditions. The investigation considers a range of parameters, including core shapes (tetragonal, hexagonal, and octagonal), core heights (0.021 m, 0.051 m, and 0.081 m), levels of pre-existing damage, and TNT charge masses (0.5 kg, 1.5 kg, and 2.5 kg), all tested under three distinct temperatures: ambient (293 K), sub-zero (193 K), and cryogenic (113 K). Blast loading is simulated using the ConWep method with a consistent stand-off distance of 0.1 m. The findings reveal that panels with octagonal cores significantly outperform other geometries, reducing front-face deflection by up to 46%. Similarly, increasing the core height leads to a more than 60% reduction in back-face deformation. Cryogenic conditions further enhance the structural response, with simulations showing faster kinetic energy decay and a smoother stress distribution across both damaged and intact models. Cryogenic panels absorbed up to 25% more internal energy while maintaining lower overall strain levels, indicating a more efficient mechanism for dissipating blast energy. Overall, the study highlights how geometric configuration, thermal environment, and damage state collectively govern the blast performance of sandwich panels, offering valuable guidance for designing high-performance protective structures in sectors such as aerospace, defense, and cryogenic systems.Publicationtype: Journal Article29 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Effects of crevice corrosion induced by biofouling on the mechanical response of engineered plate designs as an idealization of naval and marine structures(Elsevier, 2025-08-08); ; ; This study investigates the reduction in the mechanical strength of stainless-steel plates resulting from crevice corrosion induced by biofouling. A hole model based on the geometric characteristics of damage from 6-, 12-, and 36-month immersion data was developed and applied in ABAQUS CAE using the analytical mapped field feature. Finite element method (FEM) simulations were conducted using two types of loading—concentrated and uniform—with 15 random hole configurations each. The results were validated using Kirchhoff-Love plate theory. The results showed that corrosion reduces plate strength, as evidenced by increased deflection, strain, and von Mises stress with immersion duration. Under concentrated loading for 36 months, deflection increased by 10.65 %, strain by 17.22 %, and von Mises stress by 8.87 %. Under uniform loading, the increases were greater: 14.38 %, 43.26 %, and 22.03 %, respectively. A concentrated stress pattern emerged at the center of the plate under concentrated loading and spread diagonally under uniform loading. These findings provide a basis for predicting residual strength and designing biofouling-resistant marine structures.Publicationtype: Journal Article32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Data-driven fatigue assessment of welded engineering structures(2025)Publicationtype: Doctoral Thesis116 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Analysis of the ballistic impact on sandwich panel : influence of attack angle and target location in structure–bullet interaction(Springer, 2024-09-09); ; ; ; This study presents a numerical investigation of bullet impact on sandwich panel structures. This research aims to demonstrate the ideal performance of sandwich panel structures in resisting ballistic loads based on the type of core geometry and materials used. Numerical simulations were conducted using the Johnson–Cook material model and applied in ABAQUS/Explicit software. Parameters such as shot target location and bullet angle of attack were considered in this study to review the structure’s resistance to ballistic loads. The results showed that the sandwich panel structure with decagon core geometry and Armox 500 T material was optimal in resisting the impact of blunt bullets at 500–700 m/s. The contribution of this research is to provide understanding in the field of ballistics by showing the interaction between the sandwich structure and the bullet through the velocity drop that occurs on the bullet and the energy the structure can absorb. Overall, this research provides insight into improving the design and performance of protective structures.Publicationtype: Journal Article40 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Simulation of a two-dimensional ice crushing processes with the Mohr-Coulomb nodal split modelLevel ice poses a significant risk for ships, offshore-, and civil structures. Crushing loads are a relevant load case for different ice-structure interaction scenarios. In this paper, the new Mohr-Coulomb Nodal Split (MCNS) ice model is used for the first time to simulate two-dimensional brittle crushing loads for unconstrained and floating level ice conditions. The results of the presented feasibility study are in good qualitative agreement with previous experimental and numerical studies of various authors. Effects such as spatial variation of High Pressure Zones are accurately represented in the numerical MCNS model. The maximum achievable nominal contact pressures in the case of an ideal contact are in the range of the compression strength of the material model used. Whereas during the crushing process, a maximum of 40% of the compression strength is reached.Publicationtype: Conference Paper23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Internal flow effects in OTEC cold water pipe: Finite element modelling in frequency and time domain approaches(Elsevier, 2023-11-15); ; 38 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Assessment of corrosion fatigue in welded joints using 3D surface scans, digital image correlation, hardness measurements, and residual stress analysis(Elsevier, 2023-11); ; ; Corrosion can significantly reduce fatigue resistance of steel constructions including offshore support structures. This can be attributed to either localized stress concentration caused by pitting corrosion or to embrittlement of the material during the corrosion process. In addition to the stress concentrations that can arise from pitting corrosion, offshore steel structures are characterized by a significant number of notches at weld seams, which may also cause stress concentrations. Therefore, it is of great importance to study the interaction between the pre-existing notches from welds and the notches from corrosion. Thus, reference material specimens as well as butt- and fillet-welded specimens from a mild steel S355 were investigated in this study. Before being stored in a salt spray chamber, the specimens were clean blasted as usually carried out for offshore support structures. After one month of exposure, the specimens were tested against fatigue and monitored by digital image correlation (DIC). The specimens were scanned with high-resolution 3D-scanners before and after corrosion exposure. In addition, material hardness and residual stresses were investigated to quantify the influence of corrosion on the material side and the influence from the welding process. It is shown that corrosion strongly influences the weld geometry. Both, individual pits and uniform corrosion are observed at the weld toe, which is relevant for fatigue. It was also shown that the fatigue strength of welded specimens depends not only on the geometry and its degradation by corrosion, but to a greater extent on the residual stresses present after corrosion. The residual compressive stresses applied by clean blasting were partly relieved by corrosion. The fatigue tests have shown increased fatigue strength after clean blasting and subsequent reduction due to corrosion. The fatigue strength of fillet welded specimen, for example, were increased from 74 N/mm2 in its as-welded condition to 158 N/mm2 through clean blasting. However, due to corrosion, fatigue strength decreases to 98 N/mm2.Publicationtype: Journal Article47 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Evaluation of high-tensile steel using nonlinear analysis: Experiment-FE materials benchmarking of LNG carrier structures under low-temperature conditions(2023-09); ; 24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Yield Strength and Thickness Effect on Fatigue Strength of Thermal Cut Plate EdgesThe increasing size of container vessels is accompanied by an increase of plate thicknesses as well as the extensive use of higher tensile strength steels. For large plate thicknesses as well as high yield strengths, the influence of these parameters on fatigue strength of thermal cut plate edges is not well validated. This paper describes results based on fatigue tests for specimens with yield strengths of 355 to 460 MPa and plate thicknesses of 25 to 80 mm. The specimens were fabricated using gas and plasma cutting as well as usual post-treatment methods. The objective of the investigations was to verify and, if suggested by the results, to modify the current fatigue assessment procedures for thermal cut plate edges.Publicationtype: Conference Paper35 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Mechanical behavior of additively and conventionally manufactured 316L stainless steel plates joined by gas metal arc weldingCombining several additive manufactured (AM) parts to larger parts by welding may be required due the limited building volume of powder bed AM methods. Laser powder bed fusion (LPBF) has a great potential because it enables the production of nearly full-density components through AM processes; however, additional residual stresses and production defects are induced by LPBF. These residual stresses affect the residual stress state of welded AM parts. In combination with the production related defects, both alter the mechanical and—in particular—the fatigue behavior of these welded joints. In this study, various tests are performed to characterize the butt joints of 316L AM steel plates made by gas metal arc welding. To this goal, joints are produced with weld seams parallel and vertical to the layer orientation of AM plates. The results are compared to joints of conventionally rolled steel plates produced with the same welding parameter. The residual stress states in initial (unloaded) condition and after cyclic loading were determined by X-ray diffraction techniques for AM and rolled plates. Complex residual stress states were determined at the welds made of AM steel plates compared to the welds made of rolled steel plates; however, the residual stress level in the heat affected zone of the butt-welded AM steel plates was similar to the welds made of hot-rolled steel plates. After cyclic loading with a high load level, high residual stress relaxations were observed in the parent materials. The fatigue design curve for butt joints from international standards is exceeded by all three test series, but the fatigue strength of the butt joints made by LBPF and hot rolling vary significantly. This is thought to be related to differences between the AM and conventional joints in microstructure, static strength, residual stress level, and small crack-like defects that partially interact with stress concentrations at the weld transition.Publicationtype: Journal Article40