This study investigates the application of computational hemodynamic modeling, involving both FSI and CFD models, using SimVascular to simulate blood flow in the right pulmonary artery for patient-specific cardiovascular assessment. The artery’s three-dimensional geometry was reconstructed from a computed tomography (CT) image, and pressure measurements from a CardioMEMS™ device were used as clinical ground truth for validation. To represent the arterial hemodynamics, we initially formulated a fluid–structure interaction (FSI) approach to capture wall mechanics. However, given the high computational cost of fully patient-specific FSI simulations for routine clinical decision-making, we evaluated the validity of key simplifications by assuming rigid vessel walls coupled with a three-element Windkessel (3WK) model and applying a half-sine inflow waveform derived from the patient’s cardiac output. These simplifications yielded results with minimal error: the rigid-wall assumption introduced a 1.1% deviation, while the idealized waveform resulted in a 0.56 mmHg offset. Crucially, while wall rigidity was acceptable, we found that arterial compliance in the boundary conditions is non-negotiable; reducing the model to a pure resistance approach resulted in non-physiological pressures (130 mmHg). A subsequent parametric analysis examined how varying resistance (R) and compliance (C) distinctively alter the pressure waveform morphology. The results underscore the potential of combining remote monitoring data with validated computational simulations to deepen the understanding of cardiovascular dynamics and enhance diagnostic and therapeutic approaches for cardiovascular diseases.

A new semi-implicit, two-phase, double-point formulation of the Material Point Method (MPM) for soil–water interaction with seepage and free-surface flows under large deformation is presented in this paper. The approach advances the water phase implicitly while keeping the soil phase explicit, enabling stable, efficient time integration in problems that involve rapid seepage and strong free-surface motion. The proposed framework models high-Reynolds-number interphase drag through a non-linear Darcy’s law implemented for the first time within an incremental fractional step MPM formulation without enlarging the implicit solve. This methodology also enhances the numerical stability for fast flows and wave breaking via a hyperelastic constitutive treatment of slightly compressible viscous water, and mitigates spurious oscillations through a new stabilisation approach for the velocity. Robustness of soil–water interface is achieved by combining nodal-based, free-surface detection, suited for higher-order spline functions with smooth porosity–permeability transitions that avoid constitutive divergence at sharp material boundaries. Validation against laboratory benchmark cases reported in the literature, including pure-water dam break, dam-break seepage through a porous barrier, two granular-collapse tsunami experiments, and a dam-break wave over a movable granular bed, shows accurate and stable free-surface evolution, pressure time histories, seepage fronts, and wave-gauge records. Using an advanced critical-state soil model (NorSand) further improves the reproduction of granular flow kinematics. The results demonstrate that the proposed formulation is a reliable and computationally efficient tool for geotechnical hazards involving intense soil–water coupling, seepage, sediment transport and free water.

Tumor progression is an inherently multiphysical phenomenon in which interstitial fluid dynamics, biochemical transport, and cellular mechanics interact across multiple spatiotemporal scales. Classical mesh-based solvers, although accurate, impose prohibitive computational costs for the repeated evaluations demanded by inverse parameter identification and future patient-specific predictive pipelines. In this work we introduce a Physics-Informed Neural Network (PINN) framework for a tractable chemo-fluidic continuum model of tumor growth that couples an advection-diffusion-reaction (ADR) equation for the tumor volume fraction with a quasi-static Darcy pressure equation for the interstitial fluid pressure. By intentionally decoupling the solid-mechanical equilibrium, we obtain a three-equation system whose gradient structure is stable under automatic differentiation, enabling robust deep-learning optimization. The network simultaneously learns both state variables from physics constraints alone (forward problem) and recovers hidden transport parameters from sparse, noisy synthetic measurements (Data-Assimilation PINN, DA-PINN, inverse problem). We verify the forward solver against a high-resolution finite-difference (FD) reference, achieving a mean absolute error below 0.002. For the inverse problem, starting from an initial permeability estimate of 0.08 (a factor of 4x above the true value of 0.02) with only 5

Breast‐conserving surgery is typically performed with the patient in a supine position, whereas preoperative diagnostic MRI breast images are obtained with the patient in a prone position. The change in patient positioning causes significant large deformations, requiring preoperative localization of the detected lesions. Developing an individual‐specific breast biomechanical model capable of simulating these deformations remains challenging yet highly desirable. This study presents a novel approach that combines finite element analysis with the optimization of mechanical properties of breast tissues, using only surface information to construct a personalized deformation model of the breast. A visco‐hyperelastic model is employed to characterize the stress–strain relationship of breast tissue. The proposed method has been tested on 15 cases of breast cancer and achieves a tumor localization error of 8.12 ± 4.15 mm. The results show that this approach provides an accurate and realistic estimation of large breast tissue deformations and yields smaller tumor localization errors compared to previously reported methods.

We present a fully coupled hydro-thermomechanical framework for multiphase model of porous media under extreme thermomechanical conditions, possibly involving extremely large deformation, heat conduction, phase transition and internal flow. The proposed computational framework combines the hot optimal transportation meshfree (HOTM) method and a meshfree formulation of Darcy’s law. In specific, the optimal transportation theory is introduced for temporal discretization, while material-point sampling method is employed for spatial discretization of the porous media. The linear momentum and energy conservation are formulated in the Lagrangian configuration and jointly solved in the HOTM framework to predict the solid-skeleton deformation and the temperature evolution in porous media. Meanwhile, the mass conservation and Darcy’s law are formulated in the current configuration at the material-point level and solved via a weighted residual method to predict the internal fluid flow and the porosity distribution in porous media. The detailed formulation of the computational framework is stated and validated. Then, we focus on a particular application: the hot-forming process of resin-based friction composites. In this simulation, the resin-based matrix is modeled as a continuous porous medium, while particles and fibers are modeled as explicit spheres and cylinders embedded in the porous matrix. Simulations with various loading conditions are conducted to investigate the effects of loading parameters on the internal fluid flow and porosity in the product. The sensitivity of product’s porosity on loading conditions including pressure and temperature is further studied.

A semi-implicit two-phase double-point Material Point Method (MPM) formulation, based on the incremental fractional-step method to model large deformation geotechnical problems has been derived. The semi-implicit formulation has two advantages compared with the explicit approach: the time step is independent of the water phase, and the pore pressure field is more stable. The semi-implicit MPM models based on the incremental fractional-step method available in the literature consist of modelling the soil and water mixture using a single set of material points only, in order to save computational time. In this study, we further derive this formulation with two sets of material points to represent the soil and water phases separately. The stress oscillations that are frequently found in the water and soil phases are stabilised with this approach. A new stabilisation method is developed based on the modified F-bar method. The proposed method is validated with two numerical examples under small and large deformations, respectively. After that, Nor-Sand constitutive soil model is used to simulate landslides. Numerical examples show an excellent performance of the proposed coupled MPM and the stabilisation method. The formulation with two sets of material points yields significantly different but more reliable results in the landslides analysis, compared with the single-point approach. Additionally, this research shows that the additional computational cost caused by the additional water material points is acceptable. Therefore, it is recommended to use two sets of material points for certain large deformation geotechnical problems.

In this research, a new semi-implicit two-phase double-point material point method is proposed, in which the soil and water phases are modelled using two distinct sets of material points, both being stabilised with a novel approach. The Nor-Sand constitutive model is implemented to simulate more realistic soil behaviour. Some landslide numerical examples are presented to investigate the performance of the proposed method and highlight the importance of using the double-point approach. The formulation with two sets of material points shows significantly different but more reliable results in the cases of landslides, compared with the conventional single-point approach. Furthermore, this research shows that the additional computational cost given by the additional water material points is acceptable. Therefore, it is recommended to use two sets of material points for some large deformation geotechnical problems.

Debris flows can be considered a type of landslide with large velocities and long run-out distances. There are many types of debris flows, depending on the properties of the solid and fluid components of the mixture. The triggering and propagation of debris flows can be studied using a single 3D mathematical model. The computational cost can be very high because of their length, and depth-integrated models provide a good combination of accuracy and cost. Both types of models can be combined in the analysis, using 3D models for initiation and at singular points where more accuracy is wanted. As in a chain where the strength is never higher than that of the weaker link, we have to ensure that all the models are accurate enough in a joint model. This paper deals with a new depth-integrated model which can take into account the changes caused by dewatering in a debris flow.

The Material Point Method (MPM) has drawn great attention in the numerical modelling of large deformation, geotechnical problems. The popularity of MPM is mainly because its formulation shares significant similarities with the Finite Element Method. In MPM, the iteration points can move independently from the mesh, allowing for the resolution of large deformation problems. However, because of this, the original MPM formulation suffers from the well‐known cell‐crossing noise and volumetric‐locking instabilities, resulting in a strongly oscillated stress field. A novel implicit locking‐free B‐spline MPM that controls stress oscillations to a negligible level is proposed in this paper. A novel, but very straightforward B‐spline shape function implementation procedure, avoids the need for a complex material point searching algorithm, providing seamless transformation from the original MPM to this robust B‐spline MPM, aiming at modelling large‐strain geotechnical problems. The newly proposed volumetric locking mitigation strategy is also very easy to implement, which facilitates the reproducibility of this research. The proposed method is validated against three numerical studies: granular column collapse experiment, slope failure and footing with large penetration. The proposed numerical method agrees well with experiments reported in the literature and previous numerical studies. Also, these numerical examples show that the proposed method provides a more prominent stress field than other available methodologies.

The numerical study of the scaphoid fracture, although it is relatively unexplored, can be of great clinical interest since it is highly common and can result in temporary or persistent disability. In this manuscript, seven combinations of boundary conditions and contacts between adjacent bones, together with four different loads, simulating real hand movements, are assessed. Three different fracture criteria for bones are employed to study the failure of the scaphoid with the aforementioned combination of interaction conditions. The results offer an interesting view of the accuracy of the possible interaction between adjacent bones. For future calculation, it would be possible to choose a combination of the balance between precision and computational cost savings. This study provides a comprehensive assessment into the modeling of the scaphoid bone and its interactions with adjacent bones. The findings reveal that various choices of interactions can yield similar results, allowing for flexibility in selecting interaction models based on desired accuracy or computational efficiency. Ultimately, this study establishes a foundational understanding for future research on modeling scaphoid motion.

Debris flows can be considered a type of landslide with large velocities and long run-out distances. There are many types of debris flows, depending on the properties of the solid and fluid components of the mixture. The triggering and propagation of debris flows can be studied using a single 3D mathematical model. The computational cost can be very high because of their length, and depth-integrated models provide a good combination of accuracy and cost. Both types of models can be combined in the analysis, using 3D models for initiation and at singular points where more accuracy is wanted. As in a chain where the strength is never higher than that of the weaker link, we have to ensure that all the models are accurate enough in a joint model. This paper deals with a new depth-integrated model which can take into account the changes caused by dewatering in a debris flow.

In this paper, an efficient and robust methodology to simulate saturated soils subjected to low-medium frequency dynamic loadings under large deformation regime is presented. The coupling between solid and fluid phases is solved through the dynamic reduced formulation u - p(w) (solid displacement - pore water pressure) of the Biot's equations. The additional novelty lies in the employment of an explicit two-steps Newmark predictor-corrector time integration scheme that enables accurate solutions of related geomechanical problems at large strain without the usually high computational cost associated with the implicit counterparts. Shape functions based on the elegant Local Maximum Entropy approach, through the Optimal TransportationMeshfree framework, are considered to solve numerically different dynamic problems in fluid saturated porous media.

In geotechnical engineering, very often, the soil behavior varies with time. This is of particular interest in many cases such as embankments in soft clays, shear band progression in slopes or where the speed of the application of the load affects the bearing capacity of the material. In this paper, we study the extension of non-local failures using algorithms such as eigenerosion and eigensoftening, in order to evaluate the failure of weak layers. In particular, the time dependence of the progression of shear bands is analyzed through the integration of a Perzyna-type visco-plastic model with a degradation algorithm within the Optimal Transportation Meshfree (OTM) framework. The validation of the proposed algorithm is carried out through three different practical cases, showing very good agreement in all of them.

Traditionally, Biot’s formulation is employed to model the behavior of saturated soils. The u-p_w (solid displacement–pore water pressure) formulation can be considered as the standard one, since involves a good computational performance together with excellent accuracy for slow and moderate speed phenomena. Dynamic processes can be studied even if the acceleration of the water is neglected, what occurs in the undrained limit. It is well-known that u-p_w formulation might display instabilities in the undrained-incompressible limit. Several techniques have been proposed to overcome this issue, principally within an implicit time integration scheme for small strains. In this paper, a robust implementation of the divergence of the momentum equation technique is presented for an explicit u-p_w approach within the framework of optimal transportation meshfree scheme at finite strain. Several examples are provided in order to assess the good performance of the proposed methodology.

In this paper, the theoretical framework is a depth-integrated two-phase model capable of considering many essential physical aspects such as reproducing the propagation of debris flows with soil permeability ranging from high to low and considering the pore-water pressure evolution. In this model, the pore fluid is described by an additional set of depth-integrated balance equations in order to take into account the velocity of pore fluid. The model employs a frictional rheological law for the granular material, and the interstitial fluid is treated as a Newtonian fluid. A drag law describes the interaction between interstitial fluid and grains. The variables of permeability, porosity, and drag force are included in the governing equations to consider the interaction between the phases. This paper aims to extend a generalized two-phase depth-integrated model to enhance the description of the interaction between the two phases and their respective movements. It allows us to increase our understanding of the mechanism behind natural rapid landslides. To evaluate the developed approach, a set of dam-break problems has been performed. These simulations provide interesting information in simple and controlled situations on the landslide propagations with different degrees of soil permeability and the interaction between solid and fluid phases. The extended model has also been applied to simulate the dynamics of the Acheron rock avalanche, which is an appropriate benchmark to examine the applicability of the model to real cases.

Entrainment of saturated bed material increases the mobility of fast landslides. The distribution of excess pore pressures changes in the body of the landslide, as the material entering it has much lower effective confining stresses which results on much smaller apparent basal friction angles. The purpose of this paper is to enhance the Finite Differences depth integrated SPH model developed by the authors to cope with material which is flowing up the FD meshes. The model is set within an Arbitrary Lagrangian Eulerian framework (ALE), and the resulting excess pore pressure evolution model will include now advective terms in addition to the diffusive and source terms. In order to assess the importance of the proposed modification, we introduce a basal Péclet number which relates two non dimensional reference times of consolidation and erosion.

In this paper, an efficient and robust methodology to simulate saturated soils subjected to low-medium frequency dynamic loadings under large deformation regime is presented. The coupling between solid and fluid phases is solved through the dynamic reduced formulation u-p_w (solid displacement – pore water pressure) of the Biot’s equations. The additional novelty lies in the employment of an explicit two-steps Newmark predictor-corrector time integration scheme that enables accurate solutions of related geomechanical problems at large strain without the usually high computational cost associated with the implicit counterparts. Shape functions based on the elegant Local Maximum Entropy approach, through the Optimal Transportation Meshfree framework, are considered to solve numerically different dynamic problems in fluid saturated porous media.

In this paper, an efficient and robust methodology to simulate saturated soils subjected to low-medium frequency dynamic loadings under large deformation regime is presented. The coupling between solid and fluid phases is solved through the dynamic reduced formulation $$u-p_\mathrm{w}$$ (solid displacement – pore water pressure) of the Biot’s equations. The additional novelty lies in the employment of an explicit two-steps Newmark predictor-corrector time integration scheme that enables accurate solutions of related geomechanical problems at large strain without the usually high computational cost associated with the implicit counterparts. Shape functions based on the elegant Local Maximum Entropy approach, through the Optimal Transportation Meshfree framework, are considered to solve numerically different dynamic problems in fluid saturated porous media.

AbstractIn this paper, an efficient and robust methodology to simulate saturated soils subjected to low-medium frequency dynamic loadings under large deformation regime is presented. The coupling between solid and fluid phases is solved through the dynamic reduced formulation $$u-p_\mathrm{w}$$ u - p w (solid displacement – pore water pressure) of the Biot’s equations. The additional novelty lies in the employment of an explicit two-steps Newmark predictor-corrector time integration scheme that enables accurate solutions of related geomechanical problems at large strain without the usually high computational cost associated with the implicit counterparts. Shape functions based on the elegant Local Maximum Entropy approach, through the Optimal Transportation Meshfree framework, are considered to solve numerically different dynamic problems in fluid saturated porous media.