Article
Mechanics
Nasser Firouzi, Marco Amabili
Summary: The aim of this work is to develop a non-linear finite element formulation for two-dimensional growth of soft tissues, and several examples are provided to validate the proposed model.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2024)
Article
Engineering, Geological
Yijun Chen, Mostafa E. Mobasher, Haim Waisman
Summary: This study presents a novel dynamic poroelastic model for soil consolidation in saturated porous media. Numerical simulations are conducted to investigate soil consolidation under harmonic excitations and demonstrate the effectiveness and stability of the damage model.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Elisa A. Bergkamp, Clemens V. Verhoosel, Joris J. C. Remmers, David M. J. Smeulders
Summary: This paper presents a model for fluid-driven propagation of discrete fractures in poroelastic continua. The model considers the skin permeability and fluid slip effects at the fracture walls, which are particularly important for subsurface applications. The development of a fracture propagation criterion requires the incorporation of all dissipative mechanisms involved. This work proposes a thermodynamically consistent J-integral formulation for fracture propagation based on the theory of linear elastic fracture mechanics. The proposed poroelastic J-integral formulation is validated using analytical approximations in the stationary setting. The propagation criterion is implemented in an extended finite element method (X-FEM) simulation framework for propagating fractures, providing insights into the role of skin and slip effects on fluid-driven fracture propagation in poroelastic media.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Mathematics, Applied
Dmitry Ammosov, Sergei Stepanov, Aleksei Tyrylgin, Alexander Karandeev
Summary: This paper investigates the decision-making process in fractured media, where only partial measurements of fracture pressures are available. The proposed Bayesian decision-making approach allows for the computation of posterior probabilities based on partial data, enabling optimal decision-making. The results demonstrate the efficiency and accuracy of the approach in both single and multiple decision scenarios.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2024)
Article
Mathematics, Interdisciplinary Applications
Abhilash Sreekumar, Savvas P. Triantafyllou, Fabien Chevillotte
Summary: A novel Virtual Element Method (VEM) was developed to solve the mixed Biot displacement-pressure formulation governing wave propagation in porous media. The method's convergence behavior, accuracy, and efficiency were examined through illustrative examples, and a node insertion strategy was proposed to resolve non-conforming interfaces in multilayered systems. The VEM was also used to analyze the acoustic response of composite materials with complex geometries.
COMPUTATIONAL MECHANICS
(2022)
Article
Engineering, Multidisciplinary
Stijn Jonckheere, Hadrien Beriot, Olivier Dazel, Wim Desmet
Summary: This article presents an adaptive higher order finite element method for solving poroelastic models. The method ensures reliable results by using trial and error and an adaptive mechanism to meet user-defined target error. The article also discusses the applications of poroelastic materials in vibro-acoustics.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Shao-Wei Wu, Chao Jiang, G. R. Liu, De-Tao Wan, Chen Jiang
Summary: This article presents an n-sided polygonal smoothed finite element (nSFEM) for dynamic analyses of nonlinear problems in visco-hyperelastic materials undergoing large deformations. The method constructs two types of smoothing domains for the mesh of n-sided polygonal elements and uses the gradient smoothing technique to simplify the calculation of the strain displacement matrix. A simple averaging point interpolation technique is employed to calculate the shape function values on the boundary of different smoothing domains. The nSFEM demonstrates high precision, super convergence, and robustness in analyzing incompressible visco-hyperelastic problems, as verified by numerous numerical examples.
APPLIED MATHEMATICAL MODELLING
(2022)
Article
Engineering, Mechanical
Renato Poli, Rafael Gioria, Ronaldo Carrion
Summary: This paper introduces a fully coupled hydromechanical full-field reservoir simulator to consider the effects of coupled effects on the propagation of tensile hydraulic fractures in injection projects. The research findings demonstrate the significant impact of fluid injection and production history on the properties of the fractures generated. Designers should avoid using off-the-shelf hydraulic fracturing simulators for long-term projects.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Giseok Yun, Jeehwan Lee, Do-Nyun Kim
Summary: In this study, we integrated a recently proposed pure displacement-based overlapping element with a displacement-pressure mixed formulation. By utilizing low-order triangles, the overlapping element can be effectively integrated with the displacement-pressure mixed formulation without violating stability conditions. Numerical stability tests were performed to identify stable displacement-pressure combinations suitable for practical use. Additionally, the effectiveness of the mixed overlapping elements compared to traditional mixed finite elements was demonstrated through numerical examples. Our findings suggest that the original overlapping element retains its salient feature of being insensitive to mesh distortion and providing accurate results in incompressible analysis.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Physics, Multidisciplinary
Hursanay Fyhn, Santanu Sinha, Alex Hansen
Summary: We investigate steady-state two-phase flow in porous media using a dynamic pore network model. Our study focuses on the statistical distributions of volumetric flow rate and saturation within a Representative Elementary Area (REA), and shows that these distributions become independent of the size of the entire model when it is sufficiently large. This independence is essential for developing a local statistical theory for the flow and allows for a description at scales where the pore size can be neglected using differential equations.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2023)
Article
Engineering, Mechanical
Yu-Fei Wang, Song Cen, Chen-Feng Li, Qun Zhang
Summary: In this paper, the authors modify the US-ATFH8 hexahedral solid element for the analysis of anisotropic nearly-incompressible hyperelastic soft tissues. The modified formulation employs linear analytical general solutions and consistent tangent modulus for formulating the trial functions, resulting in attractive properties such as absence of locking and insensitivity to mesh distortions. Numerical tests demonstrate high accuracy and faster convergence rates compared to existing models.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Computer Science, Interdisciplinary Applications
Kaibo Hu, Young-Ju Lee, Jinchao Xu
Summary: The study introduces finite element methods for the incompressible magnetohydrodynamics (MHD) system that accurately preserve the magnetic and cross helicity, the energy law and the magnetic Gauss law at the discrete level. Numerical tests are presented to demonstrate the algorithm's performance.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Engineering, Multidisciplinary
Farzam Dadgar-Rad, Shahab Sahraee
Summary: This contribution presents a nonlinear formulation for modeling the large deformation of elastic curved beams made of fully incompressible hyperelastic materials. By applying an incompressibility constraint and a plane stress assumption, a system of three nonlinear algebraic equations involving hydrostatic pressure and normal strain in the beam cross section is obtained. This strategy allows for using three-dimensional incompressible constitutive equations and a Total Lagrangian finite element formulation due to the highly nonlinear nature of the differential equations. Performance and accuracy of the formulation are examined through numerical examples.
APPLIED MATHEMATICAL MODELLING
(2021)
Article
Biotechnology & Applied Microbiology
Vesa Anttila, Antti Saraste, Juhani Knuuti, Marja Hedman, Pekka Jaakkola, Karl -Ludwig Laugwitz, Markus Krane, Anders Jeppsson, Saara Sillanmaeki, Jaya Rosenmeier, Pernilla Zingmark, Anna Rudvik, Pavlo Garkaviy, Christina Watson, Menelas N. Pangalos, Kenneth R. Chien, Regina Fritsche-Danielson, Anna Collen, Li-Ming Gan
Summary: The first clinical study of injecting naked mRNA encoding VEGF-A (AZD8601) into the human heart showed therapeutic cardiovascular effects without serious adverse events.
Article
Mechanics
Jie Jin, Xiaoqiang Wang, Xiaohua Liu, Yanmei Xu, Detang Lu
Summary: Hydraulic fracturing model using the phase-field method is proposed in this paper for simulating fracture propagation in poroelastic media with natural caves. The model couples the flow in fracture, cave, and reservoir domains, and is solved by a staggered scheme. The results show that the presence of caves can affect the hydraulic fracture's path and velocity, and increasing the distance, injection rate, and stress difference between the fracture and cave can limit the cave effect.
Article
Engineering, Biomedical
Nathaniel S. Kelly, Danny McCree, Libera Fresiello, Nils Brynedal Ignell, Andrew N. Cookson, Azad Najar, Ina Laura Perkins, Katharine H. Fraser
Summary: This study presents a novel strategy using Computational Fluid Dynamics (CFD) to simulate the haemodynamics in the Realheart (R) total artificial heart. By comparing different computational methods, it was found that video-prescribed motion was the most accurate in predicting chamber pressures and flow rates. This method shows promise for future optimization of the Realheart (R) design and operation.
Article
Cardiac & Cardiovascular Systems
Neal M. Duggal, Ienglam Lei, Xiaoting Wu, Keith D. Aaronson, Francis D. Pagani, Hugo Y. -K. Lam, Paul C. Tang
Summary: This study examined the differences in myocardial transcriptome signatures among patients with different degrees of mitral regurgitation (MR) pre-left ventricular assist device (LVAD) implantation. The results showed that patients with moderate-severe MR have increased expression of inflammation-related genes and reduced expression of cellular proliferation genes, which may have important implications for myocardial recovery.
JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY
(2023)
Article
Cardiac & Cardiovascular Systems
Harminder Gill, Joao Fernandes, Omar Chehab, Bernard Prendergast, Simon Redwood, Amedeo Chiribiri, David Nordsletten, Ronak Rajani, Pablo Lamata
Summary: Uni-dimensional Doppler echocardiography data is the primary method for quantitatively assessing aortic stenosis, with transvalvular pressure drop being a crucial indicator of hemodynamic burden. Advanced techniques in velocity data acquisition and computational analysis have improved the accuracy and reproducibility of measurements. Three-dimensional imaging modalities allow angle-independent valve interrogation and calculation of more precise measures of the transvalvular pressure drop. This manuscript explores the fundamental physics principles underlying aortic stenosis evaluation and discusses modern techniques that may offer more accurate grading and inform appropriate management.
TRENDS IN CARDIOVASCULAR MEDICINE
(2023)
Article
Oncology
Pedro Rocha, Jiexin Zhang, Raquel Laza-Briviesca, Alberto Cruz-Bermudez, Neus Bota-Rabassedas, Beatriz Sanchez-Espiridon, Katsuhiro Yoshimura, Carmen Behrens, Wei Lu, Ximing Tang, Apar Pataer, Edwin R. Parra, Cara Haymaker, Junya Fujimoto, Stephen G. Swisher, John Heymach, Don L. Gibbons, J. Jack Lee, Boris Sepesi, Tina Cascone, Luisa M. Solis, Mariano Provencio, Ignacio I. Wistuba, Humam Kadara
Summary: This study explores immune gene programs related to tumor immunity and response to neoadjuvant chemotherapy and chemoimmunotherapy in resectable NSCLC. The findings highlight the importance of specific immune signatures and pathways in predicting treatment response.
CLINICAL CANCER RESEARCH
(2022)
Article
Computer Science, Interdisciplinary Applications
Konstantinos G. Lyras, Jack Lee
Summary: This study investigates the impact of red blood cell aggregation on hemodynamics by using multiphase simulations. The results show that red blood cell aggregation leads to a decrease in pressure, as well as changes in secondary flow patterns, red blood cell distribution, shear stresses, and velocity.
COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE
(2022)
Article
Medicine, Research & Experimental
Rui (Sammi) Tang, Jian Zhu, Tai-Tsang Chen, Fang Liu, Xun Jiang, Bo Huang, J. Jack Lee, Robert A. Beckman
Summary: This study simulated oncology trials to assess the impact of the COVID-19 pandemic and discuss potential strategies for mitigation. The results showed that COVID-19 can have a significant impact on trial outcomes, including power loss and underestimation of treatment effect size. Therefore, adjustments and improvements need to be made in trial design and data collection.
CONTEMPORARY CLINICAL TRIALS
(2022)
Article
Computer Science, Interdisciplinary Applications
Konstantinos G. Lyras, Jack Lee
Summary: This article presents a finite volume method for simulating two-phase flows with sharp fluid interfaces using a level set approach coupled with volume of fluid method. The method achieves efficiency by calculating the interface to satisfy mass conservation without explicit interface reconstruction. The algorithm provides good accuracy and mass conservation.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2022)
Letter
Radiology, Nuclear Medicine & Medical Imaging
Maria Gusseva, Daniel A. Castellanos, Joshua S. Greer, Mohamed Abdelghafar Hussein, Keren Hasbani, Gerald Greil, Surendranath R. Veeram Reddy, Tarique Hussain, Dominique Chapelle, Radomir Chabiniok
JOURNAL OF MAGNETIC RESONANCE IMAGING
(2023)
Article
Anatomy & Morphology
Doyin S. Mansell, Eva Sammut, Vito D. Bruno, Raimondo Ascione, Jonathan C. L. Rodrigues, Harinderjit S. Gill, Katharine H. Fraser, Andrew N. Cookson
Summary: In a pig experimental model of myocardial infarction, a localized and layer-specific circumferential left ventricular strain metric has been found to indicate chronic changes in ventricular function post-infarction more effectively than ejection fraction. This study analyzed clinical volume indices, global strains, and the novel strain for a large human cohort to evaluate variations in ventricular function and morphology based on age, sex, and health status. Significant differences were observed between healthy and unhealthy populations, as well as between males and females. Care must be taken to correctly index critical values to age and sex when using regional circumferential strains for assessing cardiovascular health.
JOURNAL OF ANATOMY
(2023)
Review
Cardiac & Cardiovascular Systems
Ahmed Qureshi, Gregory Y. H. Lip, David A. Nordsletten, Steven E. Williams, Oleg Aslanidi, Adelaide de Vecchi
Summary: Atrial fibrillation (AF) is a major cause of ischemic stroke, and the left atrial appendage (LAA) is recognized as the primary source of embolism. Current stroke risk stratification methods mainly rely on clinical factors, rather than thrombogenic mechanisms. Cardiac imaging and image-based biophysical modeling have emerged as valuable tools for understanding thrombogenesis. However, neither technique alone is sufficient to fully assess thrombogenicity in AF. Future development integrating cardiac imaging, in-silico modeling, and machine learning approaches may improve personalized stroke risk stratification in AF patients.
FRONTIERS IN CARDIOVASCULAR MEDICINE
(2023)
Article
Engineering, Multidisciplinary
Will Zhang, Javiera Jilberto, Gerhard Sommer, Michael S. Sacks, Gerhard A. Holzapfel, David A. Nordsletten
Summary: Biomechanics is important in diagnosing and treating heart conditions. Computational models can provide personalized treatment options but require accurate constitutive equations for biomechanical behavior prediction. A fractional viscoelastic modeling approach that accurately captures the viscoelastic response of the human myocardium was previously developed. This approach has comparable computational costs and only requires two additional material parameters. In this study, the implementation of this approach in Finite Element Analysis was presented, numerical properties were examined, and the physiological implications were explored.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Biomedical
Will Zhang, Majid Jadidi, Sayed Ahmadreza Razian, Gerhard A. Holzapfel, Alexey Kamenskiy, David A. Nordsletten
Summary: This study introduces a new viscoelastic constitutive model for the human femoropopliteal artery, which accurately describes its mechanical characteristics and time-dependent behavior. The model improves the accuracy of computational simulations and expands our knowledge of arterial mechanophysiology.
ACTA BIOMATERIALIA
(2023)
Article
Computer Science, Artificial Intelligence
E. Ferdian, D. Marlevi, J. Schollenberger, M. Aristova, E. R. Edelman, S. Schnell, C. A. Figueroa, D. A. Nordsletten, A. A. Young
Summary: The development of cerebrovascular disease is closely related to changes in intracranial flow and pressure. We developed a two-step approach using a deep residual network and physics-informed image processing to non-invasively quantify cerebrovascular hemodynamics. Our method showed good accuracy in estimating velocity and flow, as well as quantifying functional relative pressures. Additionally, we successfully applied our method to in-vivo volunteers, generating high-resolution intracranial flow images and reducing low-resolution bias in pressure estimation.
MEDICAL IMAGE ANALYSIS
(2023)
Article
Cardiac & Cardiovascular Systems
Joao Filipe Fernandes, Harminder Gill, Amanda Nio, Alessandro Faraci, Valeria Galli, David Marlevi, Malenka Bissell, Hojin Ha, Ronak Rajani, Peter Mortier, Saul G. Myerson, Petter Dyverfeldt, Tino Ebbers, David A. Nordsletten, Pablo Lamata
Summary: Non-invasive assessment of the distance to pressure recovery is possible using 4D Flow CMR tracking of blood flow momentum. Current clinical practices underestimate the pressure recovery distance in aortic stenosis, calling for re-evaluation of the methods that measure the hemodynamic burden caused by this condition.
JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE
(2023)
Article
Biophysics
Nathan D. Camarillo, Rafael Jimenez-Silva, Frances T. Sheehan
Summary: This article discusses the statistical dependence between multiple measurements from the same participant and provides recommendations for using these measurements when they are not independent.
JOURNAL OF BIOMECHANICS
(2024)
Article
Biophysics
J. Huet, A. -S. Boureau, A. Sarcher, C. Cornu, A. Nordez
Summary: Standard compression in freehand 3D ultrasound induces a bias in volume calculations, but minimal compression and gel pad methods have similar results. With a trained examiner and precautions, the bias can be minimized and become acceptable in clinical applications.
JOURNAL OF BIOMECHANICS
(2024)
Article
Biophysics
C. Lariviere, A. H. Eskandari, H. Mecheri, F. Ghezelbash, D. Gagnon, A. Shirazi-Adl
Summary: Recent developments in musculoskeletal modeling have focused on model customization. Personalization of the spine profile may affect estimates of spinal loading and stability. This study investigates the biomechanical consequences of changes in the spinal profile and finds that personalizing the spine profile has medium to large effects on trunk muscle forces and negligible to small effects on spinal loading and stability.
JOURNAL OF BIOMECHANICS
(2024)
Article
Biophysics
Luke T. Mattar, Arash B. Mahboobin, Adam J. Popchak, William J. Anderst, Volker Musahl, James J. Irrgang, Richard E. Debski
Summary: Exercise therapy fails in about 25.0% of cases for individuals with rotator cuff tears, and one reason for this failure may be the inability to strengthen and balance the muscle forces that keep the humeral head in the correct position. This study developed computational musculoskeletal models to compare the net muscle force before and after exercise therapy between successfully and unsuccessfully treated patients. The study found that unsuccessfully treated patients had less inferiorly oriented net muscle forces, which may increase the risk of impingement.
JOURNAL OF BIOMECHANICS
(2024)
Article
Biophysics
Natsuki Sado, Takeshi Edagawa, Toshihide Fujimori, Shogo Hashimoto, Yoshikazu Okamoto, Takahito Nakajima
Summary: The existing methods for predicting hip and lumbosacral joint centres in Japanese adults are biased and differ between sexes. We propose new regression equations that consider soft-tissue thickness, sex differences, and a height-directional measure, and validate them using leave-one-out cross-validation.
JOURNAL OF BIOMECHANICS
(2024)
Article
Biophysics
Peimin Yu, Xuanzhen Cen, Qichang Mei, Alan Wang, Yaodong Gu, Justin Fernandez
Summary: This study aimed to explore the intra-foot biomechanical differences among individuals with chronic ankle instability (CAI), copers, and healthy individuals during dynamic tasks. The study found that copers and CAI individuals had smaller dorsiflexion angles and copers presented a more eversion position compared to healthy participants. Copers also had greater dorsiflexion angles in the metatarsophalangeal joint and more inversion moments in the subtalar joint during certain tasks. These findings can help in designing interventions to restore ankle joint functions in CAI individuals.
JOURNAL OF BIOMECHANICS
(2024)
Article
Biophysics
Jon Skovgaard Jensen, Anders Holsgaard-Larsen, Anders Stengaard Sorensen, Per Aagaard, Jens Bojsen-Moller
Summary: This study investigates the biomechanical effects of robot-assisted body weight unloading (BWU) on gait patterns in healthy young adults. The results show that dynamic robot-assisted BWU enables reduced kinetic requirements without distorting biomechanically normal gait patterns during overground walking.
JOURNAL OF BIOMECHANICS
(2024)
