Three-dimensional Interaction Research Articles

Peridynamics topology optimization of three-dimensional structures with surface cracks for additive manufacturing

Additive manufacturing (AM) is an effective approach to fabricating intricate shapes obtained from topology optimization (TO). However, it may cause undesired manufacturing-induced defects/cracks due to high thermal residual stresses. This study proposes a PeriDynamics-enabled three-dimensional Topology Optimization method (PD-TO) for designing structures by considering surface cracks for the AM processes. The PD-TO approach employs a bi-directional evolutionary structural optimization method and uses particle discretization of geometry for mechanical analysis. Crack surfaces are generated by breaking three-dimensional nonlocal interactions of the particles, and thus, during the optimization process, complex multiple structural discontinuities can be diligently modeled. First, the proposed approach is validated by solving benchmark problems without cracks. For each benchmark geometry, the PD-TO analysis is then performed by considering different positions and numbers (single/multiple) of cracks. These analyses extensively investigate and demonstrate the effects of a priori knowledge of residual stress-induced damages/cracks on the optimum topology for additive manufacturing. Besides, the smoothing operation is applied to the optimum designs to transform voxel shapes into AM-friendly smooth surfaces. These geometries are manufactured by an extrusion-based AM process to demonstrate the practical engineering application of the proposed method. Finally, the comparison of numerical results is also supported by the experimental tests conducted on the optimized topologies. Overall, it is confirmed that the PD-TO approach is a viable and accurate optimization tool for additive manufacturing considering possible process-induced damages.

Clinical and genomic delineation of the new proximal 19p13.3 microduplication syndrome.

A small but growing body of scientific literature is emerging about clinical findings in patients with 19p13.3 microdeletion or duplication. Recently, a proximal 19p13.3 microduplication syndrome was described, associated with growth delay, microcephaly, psychomotor delay and dysmorphic features. The aim of our study was to better characterize the syndrome associated with duplications in the proximal 19p13.3 region (prox 19p13.3 dup), and to propose a comprehensive analysis of the underlying genomic mechanism. We report the largest cohort of patients with prox 19p13.3 dup through a collaborative study. We collected 24 new patients with terminal or interstitial 19p13.3 duplication characterized by array-based Comparative Genomic Hybridization (aCGH). We performed mapping, phenotype-genotype correlations analysis, critical region delineation and explored three-dimensional chromatin interactions by analyzing Topologically Associating Domains (TADs). We define a new 377 kb critical region (CR 1) in chr19: 3,116,922-3,494,377, GRCh37, different from the previously described critical region (CR 2). The new 377 kb CR 1 includes a TAD boundary and two enhancers whose common target is PIAS4. We hypothesize that duplications of CR 1 are responsible for tridimensional structural abnormalities by TAD disruption and misregulation of genes essentials for the control of head circumference during development, by breaking down the interactions between enhancers and the corresponding targeted gene.

Energetic Salts of Sensitive N,N'-(3,5-Dinitropyrazine-2,6-diyl)dinitramide Stabilized through Three-Dimensional Intermolecular Interactions.

N-nitration of 2,6-diamino-3,5-dinitropyrazine (ANPZ) leads to a sensitive energetic compound N,N'-(3,5-dinitropyrazine-2,6-diyl)dinitramide. This nitro(nitroamino) compound was stabilized by synthesizing energetic salts, dipotassium (3,5-dinitropyrazine-2,6-diyl)bis(nitroamide) (3) and diammonium (3,5-dinitropyrazine-2,6-diyl)bis(nitroamide) (4). Compounds 3 and 4 are fully characterized by single-crystal X-ray diffraction. Compound 3 exhibits a three-dimensional energetic metal-organic framework (3D EMOF) structure and an outstanding overall performance by combining high experimental density (2.10 g cm-3), good thermal stability (Td(onset) = 220 °C), and good calculated performance of detonation (D = 8300 m s-1, P = 29.9 GPa). Compound 4 has acceptable thermal stability (155 °C), moderate experimental density (1.73 g cm-3), and good calculated performance of detonation (D = 8624 m s-1, P = 30.8 GPa). The sensitivities of compounds 3 and 4 toward impact and friction were determined following standard methods (BAM). The energetic character of compounds 3 and 4 was determined using red-hot needle and heated plate tests. The results highlight a 3D EMOF (3) based on a six-membered heterocycle as a potential energetic material.

Control of three-dimensional separation due to sharp fins using co-rotating vanes ahead of quasi-conical and conical zones

This experimental investigation studies the effect of an array of 30° inclined co-rotating vanes in controlling a three-dimensional interaction generated by a 15° semi-infinite sharp fin at Mach 2.05. The array is located upstream of the quasi-conical and conical zones of interaction. The primary objective is to study variation in (i) vane chord length c/h = 7.2, 4.2, and 2.5 and (ii) vane height h/δ = 0.3, 0.5, and 0.75 for c/h = 2.5 case in controlling the interaction. Control with the smallest chord length of c/h = 2.5 and h/δ = 0.75 shows the most promising result relative to vanes with longer chord lengths. The vortex trails from this configuration penetrate deeply into the quasi-conical zone of interaction, thereby modifying it both azimuthally and radially. The plateau pressure in the conical region of interaction shows a reduction of approximately 60% with an accompanied reduction in the separation shock strength by nearly 70% for this case. Implementing control in either quasi-conical or conical zones reduces the overall control effectiveness considerably. Removing vanes ahead of quasi-conical zone reduces the effectiveness of favorably modifying the flow development in this region. The bow shock formed ahead of the first vane interacts with the three-dimensional interaction creating a pressure jump that separates the region of vortex influence from that of no control.

Validation of the plasma-wall interaction simulation code ERO2.0 by the analysis of tungsten migration in the open divertor region in the Large Helical Device

• Migration of tungsten sputtered from a tungsten-coated divertor plate was investigated. • The simulation reasonably explained the observed localization of tungsten migration. • The simulation reproduced observed tungsten deposition in the private side. • The simulated tungsten density on the plasma wetted areas disagreed with observation. Tungsten migration in the open divertor region in the Large Helical Device is analyzed for validating the three-dimensional plasma-wall interaction simulation code ERO2.0. The ERO2.0 simulation reproduced the measurement of localized tungsten migration from a tungsten-coated divertor plate installed in the inboard side of the torus. The simulation also explained the measurement of the high tungsten areal density in the private side on a carbon divertor plate, next to the tungsten-coated divertor plate, by the tungsten prompt redeposition in plasma discharges for a low magnetic field strength in a counterclockwise toroidal direction. However, the simulation disagreed with the measurement of low tungsten areal density on the plasma-wetted areas on the carbon divertor plates, which indicated that the actual erosion rate of the redeposited tungsten should be much higher than that used in the ERO2.0 code.

Chemically inducing room temperature spin-crossover in double layered magnetic refrigerants Pr1.4+Sr1.6-Mn2O7 (0.0 ≤ x ≤ 0.5)

The height of total entropy (ST) for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions. However, the participation of such transitions in layered materials is not well understood. Therefore, the purpose of this work is to investigate the interplay between double layer lattice with their single perovskite counterpart, to achieve optimal magnetocaloric performance. A series of self-doped Pr1.4+xSr1.6-xMn2O7 (0.0 ≤ x ≤ 0.5) Ruddlesden-Popper (R-P) perovskite have been prepared through the solid-state sintering method. With increasing the Pr-stoichiometry, the lattice faults have increased and the double layer lattice dramatically disintegrates into single perovskite structure. Due to the reduction of bilayer R-P phase into single perovskite the spin crossover occurs from weak bilayer (TC = 304 K) interactions towards the strong three-dimensional (TC = 308 K) interactions respectively. This series consistently develops thermomagnetic irreversibility in zero-field cooled (ZFC)-field cooled (FC) magnetization, which is indicative of a spin-glass state. The glassy nature has been ascribed collectively to the lattice strain produced because of dislocations and to an antiferromagnetic phase segregated at the surface. The maximum value of temperature average entropy change (TEC) and adiabatic temperature (ΔTad) has enhanced nearly by 4 folds from 0.53 J kg−1 K−1, 0.59 K (for x = 0.0) up to 1.85 J kg−1 K−1, 10 K (for x = 0.5) at 2.5 T, respectively. Additionally, the room temperature relative cooling power has improved from 26.94 J/kg up to 77.84 J/kg with an applied field of 2.5 T. Our findings in this work suggest that the controlled reduction of double layer lattice into single perovskite and/or existence of both phases simultaneously in bilayer R-P manganites may be very effective in obtaining the desirable characteristics of magnetocaloric effects.

Flow structures of strong interaction between an oblique shock wave and a supersonic streamwise vortex

The oblique shock/vortex interaction (OSVI) is numerically investigated based on the large-eddy simulation method. A Mach interaction between separated shock and incident shock can be found when the pressure at the recirculation region reaches a certain level. Based on the idea of spatial–temporal correlation, which considers the three-dimensional steady interaction as a two-dimensional unsteady problem, a qualitative analysis is conducted to explain complicated three-dimensional shock structures. The interaction can be regarded as a combination of the following events: the interaction between circular shock and normal shock, the reflection of shock wave on a subsonic interface, and the interaction between secondary circular shock and other shock structures. Though the original vortex has broken down, a pair of streamwise vortices can be observed in the downstream flow field, the formation of which is associated with the split of the recirculation region. Moreover, the recirculation region is found to act as a solid body, which means that the flow angle along a splitting curve can reflect the splitting speed. Three stages can be identified according to the change process of the flow angle along the splitting curve, which are rapid growth, linear growth, and decrease stages. Inspired by the studies on the shock-induced boundary layer separation, the flow field of the strong OSVI with a regular interaction is modeled to predict the initial flow angle of the splitting point which is the foundation of the study on other stages. The interaction type between separated shock and incident shock can also be judged according to this approach.

Cavitation in a periodontal pocket by an ultrasonic dental scaler: A numerical investigation

Periodontal pockets are spaces or holes surrounded by teeth under the gum line. These pockets can become filled with infection-causing bacteria resulting in tissue, bone, and tooth loss. Cavitation produced by the oscillating tip of dental ultrasonic scalers plays a significant role in routine periodontal therapy to clean these areas. Numerical studies were conducted for a scaler vibrating in a periodontal pocket which was simplified to a hole, using ABAQUS based on the finite element method. The simulations consider the three-dimensional, nonlinear, and transient interaction between the vibration and deformation of the scaler tip, the water flow around the scaler and the cavitation formation. The numerical model was validated by comparing results with experimental data for a scaler vibrating in an unbounded liquid, the displacement at the free end of the scaler and the cavitation pattern near the scaler tip displaying excellent agreement. A parametric study for a scaler vibrating in a hole has been carried out in terms of the volume of the hole, the taper ratio (the radius ratio between the circular opening and bottom of the hole), and the immersion depth of the scaler tip in the hole. The amount of cavitation generated is evaluated by the cavitation density (or the void fraction) which is the ratio of the volume of the cavitation occupied in the hole to the total volume of the hole. Numerical results indicate that the cavitation density in the hole increases with the decreasing hole volume and the increasing taper ratio. It is inferred that cleaning effects could be increased if some modifications to the scaler design could be made to increase the blocking effect of the hole during the cleaning process. Cavitation is observed in the hole even if the scaler is placed above the hole and increases with the immersion depth.

Numerical investigation of load-induced fatigue cracking in curved ramp bridge deck pavement considering tire-bridge interaction

Load-induced fatigue cracking is one of the main distresses of bridge deck pavement; however, due to the complexity of curved ramp bridge structures, it is difficult to effectively consider this damage behavior in the deck pavement design procedure. To deal with this problem, a three-dimensional (3D) tire-bridge interaction finite element (FE) model was developed in the present study to investigate the load-induced fatigue damage behavior within the curved ramp bridge deck pavement. In this FE model, an inflated tire model was developed to simulate the rolling tire load, and the Yeoh model was used to define the constitutive relationship of the hyperelastic material. In addition, the extended finite element method (XFEM) was utilized to describe the crack initiation and evolution, and a direct cycle algorithm was used to calculate the fatigue crack propagation law of deck pavement under different structural design parameters. The results indicated that the developed tire-bridge interaction FE model furnishes an in-depth insight into the fatigue crack propagation within curved ramp bridge deck pavement. The consideration of the tire-bridge interaction and structural design parameters has a significant influence on the accurate prediction of the fatigue crack evolution law within different deck pavement locations. Because the developed full-scale FE model is capable of simultaneously considering multiple factors, including the curvature radius, transverse and longitudinal slope, traffic speeds and tire-bridge interaction loads, it can be expected to be a mechanistic tool to facilitate and enhance fatigue damage analysis of curved ramp bridge deck pavement.

Evaluation of fatigue and creep-fatigue damage levels on the basis of engineering damage mechanics approach

Progressive degradation of material mechanical properties in the low cycle fatigue (LCF) and creep-fatigue (CF) interaction at high temperature affects the safe operation of in-service materials. By considering material degradation, the present work aims to establish a method for evaluating LCF and CF damage levels with wide applicability. Material-level data accumulations as well as theoretical foundations of LCF and CF are presented, including interrupted LCF and CF tests, subsequent tensile tests and energy-based damage models. A damage variable representing the degradation of material mechanical properties is then defined based on the tensile plastic strain energy density (TPSED), the physical mechanism of which is reflected in the microstructure evolution and fracture appearance. By taking into consideration the material degradation threshold in the traditional damage summation rule, a new three-dimensional (3D) damage interaction diagram is established, where the additional third axis indicates the material degradation level. Finally, taking GH4169 alloy and P92 steel as examples, this work demonstrates the implemented procedures of damage level evaluation, which has been validated via the experimental data.

A material point-finite element (MPM-FEM) model for simulating three-dimensional soil-structure interactions with the hybrid contact method

Large deformation in soils and frictional soil-structure contact are important geotechnical processes that should be considered when designing protective structures to cushion the impact of mass flows. In this paper, a numerical model combining the material point method and finite element method (MPM-FEM) is developed to simulate three-dimensional soil-structure interactions. In this model, soil with large deformation is discretized by using the MPM, while structures with small deformation are discretized by using the FEM. A hybrid contact method combining the advantages of point-point and point-segment contacts is used to model frictional soil-structure contact. In addition, to estimate energy dissipation properly, the Drucker-Prager model with the MiDi rheological relation is adopted as the constitutive model to characterize the dynamic characteristics of soil. The MPM-FEM is first validated for several geotechnical cases, including deformation of a flexible retaining wall and granular collapse, and achieves good agreement with an error smaller than 5.82%. Then, two numerical cases, i.e. impact of granular flow on a rigid structure and design of deformable structures, are studied by using the present model. It is demonstrated that the MPM-FEM model has potential applications in geotechnical engineering, especially when modelling the interaction between soil with large deformation and structures.

Gr Predictor: A Deep Learning Model for Predicting the Hydration Structures around Proteins.

Among the factors affecting biological processes such as protein folding and ligand binding, hydration, which is represented by a three-dimensional water site distribution function around the protein, is crucial. The typical methods for computing the distribution functions, including molecular dynamics simulations and the three-dimensional reference interaction site model (3D-RISM) theory, require a long computation time ranging from hours to tens of hours. Here, we propose a deep learning (DL) model that rapidly estimates the distribution functions around proteins obtained using the 3D-RISM theory from the protein 3D structure. The distribution functions predicted using our DL model are in good agreement with those obtained using the 3D-RISM theory. Particularly, the coefficient of determination between the distribution function obtained by the DL model and that obtained using the 3D-RISM theory is approximately 0.98. Furthermore, using a graphics processing unit, the prediction by the DL model is completed in less than 1 min, more than 2 orders of magnitude faster than the calculation time of the 3D-RISM theory. The position of water molecules around the protein was estimated based on the distribution function obtained by our DL model, and the position of waters estimated by our DL model was in good agreement with that of water molecules estimated using the 3D-RISM theory and of crystallographic waters. Therefore, our DL model provides a practical and efficient way to calculate the three-dimensional water site distribution functions and to estimate the position of water molecules around the protein. The program called "gr Predictor" is available under the GNU General Public License from https://github.com/YoshidomeGroup-Hydration/gr-predictor.

Numerical investigation on coupled thermo-mechanical critical response of curved ramp bridge deck pavement

This study investigated the critical response of the curved ramp bridge deck pavement under coupled thermo-mechanical loads through a three-dimensional (3D) tyre-bridge interaction numerical model. The temperature fields of bridge deck pavement in different seasons were simulated using measured air temperature and solar radiation data. The influence of seasonal temperature changes on the viscoelastic behaviour and stress accumulation of the deck pavement layer were assessed according to the changes of dissipated energy under different cyclic thermal loads. The results indicated that varying load modes could result in different damage patterns and adverse load locations. The deck pavements above the diaphragm and longitudinal clapboard have better thermal fatigue resistance when subjected to the cyclic thermal loading; while the ones near the flange cantilever panel have stronger resistance to coupled thermo-mechanical load. Compared with the tyre load, the coupled thermo-mechanical load can yield larger critical response and more potential damage initiations.

Exploring the phytoconstituents targeting TNF-α as potential lead compounds to treat inflammatory diseases: an in-silico approach

To explore the anti-inflammatory phytoconstituents from various plant sources as tumour necrosis factor- α (TNF- α )-inhibitor, a mediator involved in the inflammatory disorder, by in silico molecular docking. Based on previous findings, we performed the in silico assessment of anti-inflammatory phytoconstituents from different medicinal plants to understand their binding patterns against TNF- α (PDB ID: 6OP0) using AutoDock Vina. Molecular docking was performed by setting a grid box (25 × 25 × 25) Å centered at [– 12.817 × (– 1.618) × 19.009] Å with 0.375 Å of grid spacing. Furthermore, Discovery Studio Client 2020 program was utilized to assess two- and three-dimensional (2D and 3D) hydrogen-bond interactions concerning an amino acid of target and ligand. Physicochemical properties were reported using the Lipinski’s rule and SwissADME database to support the in silico findings. Results From the selected medicinal plants, more than 200 phytocompounds were screened against TNF- α protein with binding scores in the range of – 12.3 to – 2.5 kcal/mol. Amongst them, emodin, aloe-emodin, pongamol, purpuritenin, semiglabrin, ellagic acid, imperatorin, α -tocopherol, and octanorcucurbitacin A showed good binding affinity as – 10.6, – 10.0, – 10.5, – 10.1, – 11.2, – 10.3, – 10.1, – 10.1, and – 10.0 kcal/mol, respectively. Also, the absorption, distribution, metabolism, excretion, and toxicology (ADMET) profiles were well within acceptable limits. Based on our preliminary findings, we conclude that the selected phytoconstituents have the potential to be good anti-inflammatory candidates by inhibiting the TNF- α target. These compounds can be further optimized and validated as new therapeutic components to develop more effective and safe anti-inflammatory drugs. (i) Inflammation is a global clinical issue that involves several bio-chemical mediators. (ii) Phytoactive compounds are known to exhibit remarkable anti-inflammatory activities in traditional as well as some modern medicines. (iii) This study covers an in silico tool based findings that throw light on plant based bioactive compounds with potential for anti-inflammatory activity by inhibiting TNF- α. (iv) Precisely, 203 phyto-compounds were screened against target protein TNF- α trimer to find “best fit” based on docking score, binding energies, ADME studies, toxicity prediction, drug likeness, and molecular interactions.

Three-dimensional characteristics of crossing shock wave/turbulent boundary layer interaction in a double fin with and without micro-ramp control

The three-dimensional (3D) interactions between crossing shock waves and a turbulent boundary layer (CSWBLI) inside a symmetric double fin are experimentally studied using nanoparticle-based planar laser scattering, supersonic particle image velocimetry, and surface oil visualization. The possibility of controlling the separated flow generated by CSWBLI is considered by employing micro-ramp vortex generators. First, the fractal dimension, velocity profile, and logarithmic law of the incoming turbulent boundary layer at Mach number 2.8 are examined. Then, the flow structure and velocity distribution, which have seldom been presented in previous experiments, are measured in high resolution. The 3D behavior of the boundary layer after CSWBLI shows that the boundary layer becomes thicker behind the shock wave and converges toward the symmetry plane of the double fin. The converged effect contributes to the largest thickness of the boundary layer in the symmetry plane accompanied with a separation region near the wall. Introduction of seven equidistant micro-ramps upstream of the double fin is proved to suppress the separation region, where the arc-like vortices generated by the middle micro-ramps are found to be more sustainable along the streamwise direction. The micro-ramps can increase the momentum exchange between the boundary layer and the surrounding mainstream. At the same time, the momentum exchange induced by the micro-ramps decreases the flow velocity outside the converged region in comparison with the configuration without micro-ramps. The results obtained in this paper can provide an experimental insight into the 3D physical phenomena existing in the CSWBLI and its flow control.

Theoretical Analysis on the Stability of 1-Pyrenebutanoic Acid Succinimidyl Ester Adsorbed on Graphene.

The adsorbed structure of 1-pyrenebutanoic acid succinimidyl ester (PASE) on graphene was investigated based on density functional theory. We found two locally stable structures: a straight structure with the chainlike part of butanoic acid succinimidyl ester (BSE) lying down and a bent structure with the BSE part directed away from graphene, keeping the pyrene (Py) part adsorbed on graphene. Then, to elucidate the adsorption mechanism, we separately estimated the contributions of the Py and BSE parts to the entire PASE adsorption, and the adsorption effect of the BSE part was found to be secondary in comparison to the contribution of the Py. Next, the mobility of the BSE part at room temperature was confirmed by the activation energy barrier between straight and bent structures. To take account of the external environment, we considered the presence of amino acids and the hydration effect by a three-dimensional reference interaction site model. The contributions of glycine molecules and the solvent environment to stabilizing the bent PASE structure relative to the straight PASE structure were found. Therefore, the effect of the external environment around PASE is of importance when the standing-up process of the BSE part from graphene is considered.

Touch-Move-Release: Studies of Surface and Motion Gestures for Mobile Augmented Reality

Despite a broad range of mobile AR applications available to date, the majority still primarily use surface gestures, i.e., gesturing on the touch screen surface of the device and do not utilise the affordance of three-dimensional user interaction that AR interfaces support. In this research, we compared two methods of gesture interaction for mobile AR applications: Surface Gestures and Motion Gestures, which take advantage of the spatial information of the mobile device. We have conducted two user studies: an elicitation study (n = 21) and a validation study (n = 10). The first study elicited two sets of 504 gestures, surface and motion gestures, for 12 everyday mobile AR tasks. The two sets of gestures were classified and compared in terms of goodness, ease of use, and engagement. As expected, the participants’ elicited surface gestures are familiar and easy to use, while motion gestures were found more engaging. Using design patterns derived from the elicited motion gestures, we proposed a novel interaction technique called “TMR” (Touch-Move-Release). Through validation study we found that the TMR motion gesture enhanced engagement and provided a better game experience. In contrast, the surface gesture provided higher precision resulting in higher accuracy and was easier to use. Finally, we discuss the implications of our findings and give our design recommendations for using the elicited gestures.

3D-RISM-AI: A Machine Learning Approach to Predict Protein-Ligand Binding Affinity Using 3D-RISM.

Hydration free energy (HFE) is a key factor in improving protein–ligand binding free energy (BFE) prediction accuracy. The HFE itself can be calculated using the three-dimensional reference interaction model (3D-RISM); however, the BFE predictions solely evaluated using 3D-RISM are not correlated to the experimental BFE for abundant protein–ligand pairs. In this study, to predict the BFE for multiple sets of protein–ligand pairs, we propose a machine learning approach incorporating the HFEs obtained using 3D-RISM, termed 3D-RISM-AI. In the learning process, structural metrics, intra-/intermolecular energies, and HFEs obtained via 3D-RISM of ∼4000 complexes in the PDBbind database (ver. 2018) were used. The BFEs predicted using 3D-RISM-AI were well correlated to the experimental data (Pearson’s correlation coefficient of 0.80 and root-mean-square error of 1.91 kcal/mol). As important factors for the prediction, the difference in the solvent accessible surface area between the bound and unbound structures and the hydration properties of the ligands were detected during the learning process.

Nested epistasis enhancer networks for robust genome regulation.

Mammalian genomes have multiple enhancers spanning an ultralong distance (>megabases) to modulate important genes, but it is unclear how these enhancers coordinate to achieve this task. We combine multiplexed CRISPRi screening with machine learning to define quantitative enhancer-enhancer interactions. We find that the ultralong distance enhancer network has a nested multilayer architecture that confers functional robustness of gene expression. Experimental characterization reveals that enhancer epistasis is maintained by three-dimensional chromosomal interactions and BRD4 condensation. Machine learning prediction of synergistic enhancers provides an effective strategy to identify noncoding variant pairs associated with pathogenic genes in diseases beyond genome-wide association studies analysis. Our work unveils nested epistasis enhancer networks, which can better explain enhancer functions within cells and in diseases.

A three-dimensional fluid-structure interaction model based on SPH and lattice-spring method for simulating complex hydroelastic problems

The present work revolves around the development of a 3D particle-based Fluid-Structure Interaction (FSI) solver to simulate hydroelastic problems that involve free surface. The three-dimensional Volume-Compensated Particle Method (VCPM) for modelling deformable solid bodies is developed within the open-source SPH software package DualSPHysics. Complex 3D FSI problems are readily simulated within a reasonable time frame thanks to the parallel scalability of DualSPHysics on both CPU and GPU. The Sequential Staggered (SS) scheme paired with a multiple time-stepping procedure is implemented in DualSPHysics for coupling the SPH and VCPM models. It is found that the SPH-VCPM method is computationally more efficient than the previously reported SPH-TLSPH method. Extensive validations have been performed based on some very recent 3D experimental setups that involve violent free surface and complex structural dynamics. Findings from this research highlight the capability of the 3D SPH-VCPM model to reproduce some of the physical observations that were not captured by previous 2D studies. Some preliminary 3D FSI results involving solid fracture are also demonstrated.