Subjects -> COMPUTER SCIENCE (Total: 2313 journals)
    - ANIMATION AND SIMULATION (33 journals)
    - ARTIFICIAL INTELLIGENCE (133 journals)
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    - COMPUTER SCIENCE (1305 journals)
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COMPUTER SCIENCE (1305 journals)            First | 1 2 3 4 5 6 7 | Last

Showing 201 - 400 of 872 Journals sorted alphabetically
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 12)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 11)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 1)
Computational Optimization and Applications     Hybrid Journal   (Followers: 9)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 15)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 35)
Computational Toxicology     Hybrid Journal  
Computer     Full-text available via subscription   (Followers: 141)
Computer Aided Surgery     Open Access   (Followers: 5)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Communications     Hybrid Journal   (Followers: 19)
Computer Engineering and Applications Journal     Open Access   (Followers: 8)
Computer Journal     Hybrid Journal   (Followers: 7)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 25)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 10)
Computer Methods in Biomechanics and Biomedical Engineering : Imaging & Visualization     Hybrid Journal  
Computer Music Journal     Hybrid Journal   (Followers: 18)
Computer Physics Communications     Hybrid Journal   (Followers: 9)
Computer Science - Research and Development     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 15)
Computer Science and Information Technology     Open Access   (Followers: 12)
Computer Science Education     Hybrid Journal   (Followers: 15)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Review     Hybrid Journal   (Followers: 12)
Computer Standards & Interfaces     Hybrid Journal   (Followers: 3)
Computer Supported Cooperative Work (CSCW)     Hybrid Journal   (Followers: 8)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 9)
Computer-Aided Design and Applications     Hybrid Journal   (Followers: 6)
Computers     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 12)
Computers & Education     Hybrid Journal   (Followers: 91)
Computers & Electrical Engineering     Hybrid Journal   (Followers: 8)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 9)
Computers & Structures     Hybrid Journal   (Followers: 43)
Computers & Education Open     Open Access   (Followers: 2)
Computers & Industrial Engineering     Hybrid Journal   (Followers: 6)
Computers and Composition     Hybrid Journal   (Followers: 11)
Computers and Education: Artificial Intelligence     Open Access   (Followers: 2)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 7)
Computers and Geotechnics     Hybrid Journal   (Followers: 12)
Computers in Biology and Medicine     Hybrid Journal   (Followers: 11)
Computers in Entertainment     Hybrid Journal  
Computers in Human Behavior Reports     Open Access  
Computers in Industry     Hybrid Journal   (Followers: 7)
Computers in the Schools     Hybrid Journal   (Followers: 8)
Computers, Environment and Urban Systems     Hybrid Journal   (Followers: 11)
Computerworld Magazine     Free   (Followers: 2)
Computing     Hybrid Journal   (Followers: 2)
Computing and Software for Big Science     Hybrid Journal   (Followers: 1)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 31)
Computing Reviews     Full-text available via subscription   (Followers: 1)
Concurrency and Computation: Practice & Experience     Hybrid Journal  
Connection Science     Hybrid Journal  
Control Engineering Practice     Hybrid Journal   (Followers: 46)
Cryptologia     Hybrid Journal   (Followers: 3)
CSI Transactions on ICT     Hybrid Journal   (Followers: 2)
Cuadernos de Documentación Multimedia     Open Access  
Current Science     Open Access   (Followers: 116)
Cyber-Physical Systems     Hybrid Journal  
Cyberspace : Jurnal Pendidikan Teknologi Informasi     Open Access  
DAIMI Report Series     Open Access  
Data     Open Access   (Followers: 4)
Data & Policy     Open Access   (Followers: 3)
Data Science and Engineering     Open Access   (Followers: 6)
Data Technologies and Applications     Hybrid Journal   (Followers: 209)
Data-Centric Engineering     Open Access  
Datenbank-Spektrum     Hybrid Journal   (Followers: 1)
Datenschutz und Datensicherheit - DuD     Hybrid Journal  
Decision Analytics     Open Access   (Followers: 3)
Decision Support Systems     Hybrid Journal   (Followers: 13)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 33)
Digital Biomarkers     Open Access   (Followers: 1)
Digital Chemical Engineering     Open Access  
Digital Chinese Medicine     Open Access  
Digital Creativity     Hybrid Journal   (Followers: 11)
Digital Experiences in Mathematics Education     Hybrid Journal   (Followers: 2)
Digital Finance : Smart Data Analytics, Investment Innovation, and Financial Technology     Hybrid Journal   (Followers: 3)
Digital Geography and Society     Open Access  
Digital Government : Research and Practice     Open Access   (Followers: 1)
Digital Health     Open Access   (Followers: 10)
Digital Journalism     Hybrid Journal   (Followers: 7)
Digital Medicine     Open Access   (Followers: 3)
Digital Platform: Information Technologies in Sociocultural Sphere     Open Access   (Followers: 1)
Digital Policy, Regulation and Governance     Hybrid Journal   (Followers: 2)
Digital War     Hybrid Journal   (Followers: 1)
Digitale Welt : Das Wirtschaftsmagazin zur Digitalisierung     Hybrid Journal  
Digitális Bölcsészet / Digital Humanities     Open Access   (Followers: 2)
Disaster Prevention and Management     Hybrid Journal   (Followers: 30)
Discours     Open Access   (Followers: 1)
Discourse & Communication     Hybrid Journal   (Followers: 26)
Discover Internet of Things     Open Access   (Followers: 2)
Discrete and Continuous Models and Applied Computational Science     Open Access  
Discrete Event Dynamic Systems     Hybrid Journal   (Followers: 3)
Discrete Mathematics & Theoretical Computer Science     Open Access   (Followers: 1)
Discrete Optimization     Full-text available via subscription   (Followers: 7)
Displays     Hybrid Journal  
Distributed and Parallel Databases     Hybrid Journal   (Followers: 2)
e-learning and education (eleed)     Open Access   (Followers: 39)
Ecological Indicators     Hybrid Journal   (Followers: 22)
Ecological Informatics     Hybrid Journal   (Followers: 3)
Ecological Management & Restoration     Hybrid Journal   (Followers: 15)
Ecosystems     Hybrid Journal   (Followers: 32)
Edu Komputika Journal     Open Access   (Followers: 1)
Education and Information Technologies     Hybrid Journal   (Followers: 53)
Educational Philosophy and Theory     Hybrid Journal   (Followers: 10)
Educational Psychology in Practice: theory, research and practice in educational psychology     Hybrid Journal   (Followers: 13)
Educational Research and Evaluation: An International Journal on Theory and Practice     Hybrid Journal   (Followers: 7)
Educational Theory     Hybrid Journal   (Followers: 9)
Egyptian Informatics Journal     Open Access   (Followers: 5)
Electronic Commerce Research and Applications     Hybrid Journal   (Followers: 5)
Electronic Design     Partially Free   (Followers: 125)
Electronic Letters on Computer Vision and Image Analysis     Open Access   (Followers: 10)
Elektron     Open Access  
Empirical Software Engineering     Hybrid Journal   (Followers: 8)
Energy for Sustainable Development     Hybrid Journal   (Followers: 13)
Engineering & Technology     Hybrid Journal   (Followers: 22)
Engineering Applications of Computational Fluid Mechanics     Open Access   (Followers: 23)
Engineering Computations     Hybrid Journal   (Followers: 3)
Engineering Economist, The     Hybrid Journal   (Followers: 4)
Engineering Optimization     Hybrid Journal   (Followers: 19)
Engineering With Computers     Hybrid Journal   (Followers: 5)
Enterprise Information Systems     Hybrid Journal   (Followers: 2)
Entertainment Computing     Hybrid Journal   (Followers: 2)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 7)
Environmental Communication: A Journal of Nature and Culture     Hybrid Journal   (Followers: 16)
EPJ Data Science     Open Access   (Followers: 10)
ESAIM: Control Optimisation and Calculus of Variations     Open Access   (Followers: 2)
Ethics and Information Technology     Hybrid Journal   (Followers: 64)
eTransportation     Open Access   (Followers: 1)
EURO Journal on Computational Optimization     Open Access   (Followers: 5)
EuroCALL Review     Open Access  
European Food Research and Technology     Hybrid Journal   (Followers: 8)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
European Journal of Computational Mechanics     Hybrid Journal   (Followers: 1)
European Journal of Information Systems     Hybrid Journal   (Followers: 85)
European Journal of Law and Technology     Open Access   (Followers: 18)
European Journal of Political Theory     Hybrid Journal   (Followers: 27)
Evolutionary Computation     Hybrid Journal   (Followers: 11)
Fibreculture Journal     Open Access   (Followers: 9)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 5)
Fixed Point Theory and Applications     Open Access  
Focus on Catalysts     Full-text available via subscription  
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 5)
Forensic Science International: Digital Investigation     Full-text available via subscription   (Followers: 317)
Formal Aspects of Computing     Hybrid Journal   (Followers: 3)
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Forschung     Hybrid Journal   (Followers: 1)
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and Trends® in Databases     Full-text available via subscription   (Followers: 2)
Foundations and Trends® in Human-Computer Interaction     Full-text available via subscription   (Followers: 5)
Foundations and Trends® in Information Retrieval     Full-text available via subscription   (Followers: 30)
Foundations and Trends® in Networking     Full-text available via subscription   (Followers: 1)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 7)
Foundations and Trends® in Theoretical Computer Science     Full-text available via subscription   (Followers: 1)
Foundations of Computational Mathematics     Hybrid Journal  
Foundations of Computing and Decision Sciences     Open Access  
Frontiers in Computational Neuroscience     Open Access   (Followers: 23)
Frontiers in Computer Science     Open Access   (Followers: 1)
Frontiers in Digital Health     Open Access   (Followers: 4)
Frontiers in Digital Humanities     Open Access   (Followers: 7)
Frontiers in ICT     Open Access  
Frontiers in Neuromorphic Engineering     Open Access   (Followers: 2)
Frontiers in Research Metrics and Analytics     Open Access   (Followers: 4)
Frontiers of Computer Science in China     Hybrid Journal   (Followers: 2)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 3)
Frontiers of Information Technology & Electronic Engineering     Hybrid Journal  
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 9)
Functional Analysis and Its Applications     Hybrid Journal   (Followers: 3)
Future Computing and Informatics Journal     Open Access  
Future Generation Computer Systems     Hybrid Journal   (Followers: 2)
Geo-spatial Information Science     Open Access   (Followers: 7)
Geoforum Perspektiv     Open Access  
GeoInformatica     Hybrid Journal   (Followers: 7)
Geoinformatics FCE CTU     Open Access   (Followers: 8)
GetMobile : Mobile Computing and Communications     Full-text available via subscription   (Followers: 1)
Government Information Quarterly     Hybrid Journal   (Followers: 28)
Granular Computing     Hybrid Journal  
Graphics and Visual Computing     Open Access  
Grey Room     Hybrid Journal   (Followers: 16)
Group Dynamics : Theory, Research, and Practice     Full-text available via subscription   (Followers: 15)
Groups, Complexity, Cryptology     Open Access   (Followers: 2)
HardwareX     Open Access  
Harvard Data Science Review     Open Access   (Followers: 3)
Health Services Management Research     Hybrid Journal   (Followers: 16)
Healthcare Technology Letters     Open Access  
High Frequency     Hybrid Journal  
High-Confidence Computing     Open Access   (Followers: 1)
Home Cultures     Full-text available via subscription   (Followers: 7)
Home Health Care Management & Practice     Hybrid Journal   (Followers: 1)

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Similar Journals
Journal Cover
Computational Mechanics
Journal Prestige (SJR): 1.775
Citation Impact (citeScore): 3
Number of Followers: 11  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1432-0924 - ISSN (Online) 0178-7675
Published by Springer-Verlag Homepage  [2469 journals]
  • Mathematical foundations of FEM-cluster based reduced order analysis
           method and a spectral analysis algorithm for improving the accuracy

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      Abstract: Abstract As a reduced order homogenization approach, the FEM-Cluster based reduced order Analysis method (FCA) proposed by Cheng et al. provides an efficient approach to predict the nonlinear effective properties of heterogeneous materials. In its improved version, the clustered Minimum Complementary Energy (MCE) approach is adopted for the computations of incremental strain–stress relation. This work mainly focuses on the mathematical foundations of FCA with clustered MCE. The completeness of the interaction matrix as the clustered self-equilibrium stress space is proved, and the prediction error of FCA solution is analyzed. The deductions also reveal that some bases of the clustered self-equilibrium stress space denoted by the interaction matrix may contradict the basic hypothesis of the cluster-based reduce order methods, and they are mainly responsible for the error of FCA. According to this observation, a spectral analysis algorithm is developed to refine the interaction matrix and improve the accuracy of FCA.
      PubDate: 2022-06-01
       
  • Improved hyper-reduction approach for the forced vibration analysis of
           rotating components

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      Abstract: Abstract Forced vibration analysis is an indispensable process for the design of a rotating component. However, rather expensive nonlinear static and linear frequency response analyses are usually accompanied by a frequency domain analysis. The traditional mode-superposition method (MSM) effectively reduces the cost of the frequency response analysis. However, the nonlinear static analysis of earlier processes remains as the computational bottleneck. In this paper, the application of the hyper-reduction method will be proposed along with the model order reduction (MOR) framework for rotating component forced vibration analysis. The energy-conserving sampling and weighting (ECSW) method will be employed for the nonlinear iterative computation. The pre-stressed stiffness matrix of the reduced finite elements (FEs) resulting from the ECSW will be used for the post computation stage. Also, a variety of MOR will be attempted for the performance comparison, including MSM, proper orthogonal decomposition (POD)-based reduced order model (ROM), and a hybrid approach. It is found that the present ECSW-combined MOR will significantly relieve the computational bottleneck, provide a minimal loss of accuracy, and be compatible with both nonlinear and linear analyses of the rotating component forced vibration analysis.
      PubDate: 2022-06-01
       
  • Large deflection of composite beams by finite elements with node-dependent
           kinematics

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      Abstract: Abstract In this paper, the use of the node-dependent kinematics concept for the geometrical nonlinear analysis of composite one-dimensional structures is proposed With the present approach, the kinematics can be independent in each element node. Therefore the theory of structures changes continuously over the structural domain, describing remarkable cross-section deformation with higher-order kinematics and giving a lower-order kinematic to those portion of the structure which does not require a refinement. In this way, the reliability of the simulation is ensured, keeping a reasonable computational cost. This is possible by Carrera unified formulation, which allows writing finite element nonlinear equilibrium and incremental equations in compact and recursive form. Compact and thin-walled composite structures are analyzed, with symmetric and unsymmetric loading conditions, to test the present approach when dealing with warping and torsion phenomena. Results show how finite element models with node-dependent behave as well as ones with uniform highly refined kinematic. In particular, zones which undergo remarkable deformations demand high-order theories of structures, whereas a lower-order theory can be employed if no local phenomena occur: this is easily accomplished by node-dependent kinematics analysis.
      PubDate: 2022-06-01
       
  • A comparative review of peridynamics and phase-field models for
           engineering fracture mechanics

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      Abstract: Abstract Computational modeling of the initiation and propagation of complex fracture is central to the discipline of engineering fracture mechanics. This review focuses on two promising approaches: phase-field (PF) and peridynamic (PD) models applied to this class of problems. The basic concepts consisting of constitutive models, failure criteria, discretization schemes, and numerical analysis are briefly summarized for both models. Validation against experimental data is essential for all computational methods to demonstrate predictive accuracy. To that end, the Sandia Fracture Challenge and similar experimental data sets where both models could be benchmarked against are showcased. Emphasis is made to converge on common metrics for the evaluation of these two fracture modeling approaches. Both PD and PF models are assessed in terms of their computational effort and predictive capabilities, with their relative advantages and challenges are summarized.
      PubDate: 2022-06-01
       
  • Effective hyperelastic material parameters from microstructures
           constructed using the planar Boolean model

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      Abstract: Abstract We construct two-dimensional, two-phase random heterogeneous microstructures by stochastic simulation using the planar Boolean model, which is a random collection of overlapping grains. The structures obtained are discretized using finite elements. A heterogeneous Neo-Hooke law is assumed for the phases of the microstructure, and tension tests are simulated for ensembles of microstructure samples. We determine effective material parameters, i.e., the effective Lamé moduli \(\lambda ^*\) and \(\mu ^*\) , on the macroscale by fitting a macroscopic material model to the microscopic stress data, using stress averaging over many microstructure samples. The effective parameters \(\lambda ^*\) and \(\mu ^*\) are considered as functions of the microscale material parameters and the geometric parameters of the Boolean model including the grain shape. We also consider the size of the Representative Volume Element (RVE) given a precision and an ensemble size. We use structured and unstructured meshes and also provide a comparison with the FE \(^2\) method.
      PubDate: 2022-06-01
       
  • A damage phase-field model for fractional viscoelastic materials in finite
           strain

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      Abstract: Abstract This paper proposes a thermodynamically consistent phase-field damage model for viscoelastic materials following the strategy developed by Boldrini et al. (Methods Appl Mech Eng 312:395–427, 2016). Suitable free-energy and pseudo-potentials of dissipation are developed to build a model leading to a stress-strain relation, under the assumption of finite strain, in terms of fractional derivatives. A novel degradation function, which properly couples stress response and damage evolution for viscoelastic materials, is proposed. We obtain a set of differential equations that accounts for the evolution of motion, damage, and temperature. In the present work, for simplicity, this model is numerically solved for isothermal cases by using a semi-implicit/explicit scheme. Several numerical tests, including fitting with experimental data, show that the developed model accounts appropriately for damage in viscoelastic materials for small and finite strains. Non-isothermal numerical simulations will be considered in future works.
      PubDate: 2022-06-01
       
  • A digital-twin and machine-learning framework for precise heat and energy
           management of data-centers

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      Abstract: Abstract The massive growth in data-centers has led to increased interest and regulations for management of waste heat and its utilization. This work seeks to develop a combined Digital-Twin and Machine-Learning framework to optimize such systems by controlling both the ventilation and the cooling of the bases of data units/processors in the system. This framework ascertains optimal cooling strategies to deliver a target temperature in the system using a minimum amount of energy. A model problem is constructed for a data-center, where the design variables are the flow rates and air-cooling at multiple ventilation ports and ground-level conduction-based base-cooling of processors. A thermo-fluid model, based on the Navier–Stokes equations and the first law of thermodynamics, for the data-center is constructed and a rapid, stencil-based, iterative solution method is developed. This is then combined with a genomic-based machine-learning algorithm to develop a digital-twin (digital-replica) of the system that can run in real-time or faster than the actual physical system, making it suitable as either a design tool or an adaptive controller. Numerical examples are provided to illustrate the framework.
      PubDate: 2022-06-01
       
  • Dynamic brittle fracture with a new energy limiter-based scalar damage
           model

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      Abstract: Abstract We present a new scalar damage model for dynamic brittle fracture. In contrast to existing damage theories, the internal damage variable is alternatively derived based on energy limiter theory, directly tightening to its physical meaning. Finite element implementation for the developed approach at small strain towards localized brittle failure is given. We integrate the energy decomposition into the theory to eliminate nonphysical damaged phenomenon when cracks develop in compression domain, while the crack band theory is employed to treat mesh sensitivity. As a result, the current model does not involve any length scale parameter, and therefore nor diffusive equation of damage evolution characterizing the degradation of material stiffness is required. Two simple methods for estimating crack-tip velocity and dissipated energy are provided. Discrete forms of governing equation are solved by a simple staggered scheme in an effective manner. Several numerical examples for dynamic brittle fracture including crack branching are studied.
      PubDate: 2022-06-01
       
  • A viscoelastic model of geometry-constraint-based non-ordinary state-based
           peridynamics with progressive damage

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      Abstract: Abstract In this work, the geometry-constraint-based non-ordinary state-based peridynamic (GC-NOSBPD) model is further generalized to study the mechanical responses and rate-dependent fracture behaviors of viscoelastic materials. The viscoelasticity is generated by directly incorporating the classical viscoelastic constitutive relation in the form of the Generalized Maxwell Model, which is expressed as Prony-series type expansion, into the GC-NOSBPD framework. A strain-based scalar damage variable only driven by elastic energy, whose evolution follows a rate-independent law, is proposed to describe the progressive growth of the mode-I crack. Combining the rate-independent damage variable and viscoelasticity results in a rate-dependent damage model in the hypothesis that the fracture of viscoelastic material is driven by both elastic and viscous components of the energy. The fidelity of this model is established in the absence of damage by comparison with the benchmark solution for the viscoelastic response of a 3D bar subjected to various load histories. Further, the proposed model is employed to simulate two quasi-static fracture tests under various loading rates: a three-point bend fracture test for concrete and a double-cantilever-beam delamination test for rubber interface. These numerical results agree well with experimental tests, showing that the proposed model can effectively capture rate-dependent crack propagation.
      PubDate: 2022-06-01
       
  • A predictive multiphase model of silica aerogels for building envelope
           insulations

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      Abstract: Abstract This work develops a systematic uncertainty quantification framework to assess the reliability of prediction delivered by physics-based material models in the presence of incomplete measurement data and modeling error. The framework consists of global sensitivity analysis, Bayesian inference, and forward propagation of uncertainty through the computational model. The implementation of this framework on a new multiphase model of novel porous silica aerogel materials is demonstrated to predict the thermomechanical performances of a building envelope insulation component. The uncertainty analyses rely on sampling methods, including Markov-chain Monte Carlo and a mixed finite element solution of the multiphase model. Notable features of this work are investigating a new noise model within the Bayesian inversion to prevent biased estimations and characterizing various sources of uncertainty, such as measurements variabilities, model inadequacy in capturing microstructural randomness, and modeling errors incurred by the theoretical model and numerical solutions.
      PubDate: 2022-06-01
       
  • How drugs modulate the performance of the human heart

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      Abstract: Abstract Many drugs interact with ion channels in the cells of our heart and trigger heart rhythm disorders with potentially fatal consequences. Computational modeling can provide mechanistic insight into the onset and propagation of drug-induced arrhythmias, but the effect of drugs on the mechanical performance of the heart remains poorly understood. Here we establish a multiphysics framework that integrates the biochemical, electrical, and mechanical effects of drugs, from cellular excitation to cardiac contraction. For the example of the drug dofetilide, we show that drug concentrations of 5x and 8x increase the heart rate to 122 and 114 beats per minute, increase myofiber stretches by 5%, and decrease overall tissue relaxation by 6%. This results in inter-ventricular and atrial-ventricular dyssynchronies and changes in cardiac output by \(-2.5\) % and +7%. Our results emphasize the need for multiphysics modeling to better understand the mechanical implications of drug-induced arrhythmias. Knowing how different drug concentrations affect the performance of the heart has important clinical implications in drug safety evaluation and personalized medicine.
      PubDate: 2022-06-01
       
  • Fuzzy forward dynamics of distinct gait phases with a prosthetic foot

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      Abstract: Abstract This work considers epistemic uncertainty in the form of fuzzy parameters in a multibody forward dynamics simulation of the human leg with a prosthetic foot. The thigh and shank are modelled as rigid bodies while the prosthetic foot, modelled after a carbon spring prosthesis, is represented by a predeformed geometrically exact beam model. A variational integrator is used to solve the equations of motion in the forward dynamics simulation and the Graph Follower algorithm is used to include epistemic uncertainty. Two cases are considered. Large movements are examined using a pendulum swing, similar to the swing phase during human gait. To validate the deformation of the prosthesis, a second case is examined, where the prosthesis is fixed in space and deforms under the weight of the body segments. Both cases consider a fuzzy Young’s modulus and determine the envelopes of the resulting uncertain target output. The Graph Follower algorithm was modified to substantially increase computational efficiency, enabling the propagation of fuzzy uncertainty through the complex multibody model with rigid and flexible bodies.
      PubDate: 2022-05-22
       
  • How viscous is the beating heart' Insights from a computational study

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      Abstract: Abstract Understanding tissue rheology is critical to accurately model the human heart. While the elastic properties of cardiac tissue have been extensively studied, its viscous properties remain an issue of ongoing debate. Here we adopt a viscoelastic version of the classical Holzapfel Ogden model to study the viscous timescales of human cardiac tissue. We perform a series of simulations and explore stress–relaxation curves, pressure–volume loops, strain profiles, and ventricular wall strains for varying viscosity parameters. We show that the time window for model calibration strongly influences the parameter identification. Using a four-chamber human heart model, we observe that, during the physiologically relevant time scales of the cardiac cycle, viscous relaxation has a negligible effect on the overall behavior of the heart. While viscosity could have important consequences in pathological conditions with compromised contraction or relaxation properties, we conclude that, for simulations within the physiological range of a human heart beat, we can reasonably approximate the human heart as hyperelastic.
      PubDate: 2022-05-13
       
  • Correction to: A damage phase-field model for fractional viscoelastic
           materials in finite strain

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      Abstract: A Correction to this paper has been published: 10.1007/s00466-022-02145-2
      PubDate: 2022-05-09
       
  • Model-free data-driven simulation of inelastic materials using structured
           data sets, tangent space information and transition rules

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      Abstract: Abstract Model-free data-driven computational mechanics replaces phenomenological constitutive functions by numerical simulations based on data sets of representative samples in stress-strain space. The distance of strain and stress pairs from the data set is minimized, subject to equilibrium and compatibility constraints. Although this method operates well for non-linear elastic problems, there are challenges dealing with history-dependent materials, since one and the same point in stress-strain space might correspond to different material behaviour. In recent literature, this issue has been treated by including local histories into the data set. However, there is still the necessity to include models for the evolution of specific internal variables. Thus, a mixed formulation of classical and data-driven modeling is obtained. In the presented approach, the data set is augmented with directions in the tangent space of points in stress-strain space. Moreover, the data set is divided into subsets corresponding to different material behaviour. Based on this classification, transition rules map the modeling points to the various subsets. The approach will be applied to non-linear elasticity and elasto-plasticity with isotropic hardening.
      PubDate: 2022-05-09
       
  • A new method based on Taylor expansion and nearest-node strategy to impose
           Dirichlet and Neumann boundary conditions in ordinary state-based
           Peridynamics

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      Abstract: Abstract Peridynamics is a non-local continuum theory which is able to model discontinuities in the displacement field, such as crack initiation and propagation in solid bodies. However, the non-local nature of the theory generates an undesired stiffness fluctuation near the boundary of the bodies, phenomenon known as “surface effect”. Moreover, a standard method to impose the boundary conditions in a non-local model is not currently available. We analyze the entity of the surface effect in ordinary state-based peridynamics by employing an innovative numerical algorithm to compute the peridynamic stress tensor. In order to mitigate the surface effect and impose Dirichlet and Neumann boundary conditions in a peridynamic way, we introduce a layer of fictitious nodes around the body, the displacements of which are determined by multiple Taylor series expansions based on the nearest-node strategy. Several numerical examples are presented to demonstrate the effectiveness and accuracy of the proposed method.
      PubDate: 2022-05-09
       
  • The parametrized superelement approach for lattice joint modelling and
           simulation

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      Abstract: Abstract From large scale structures such as bridges and cranes to small-scale structures such as lattices, mechanical structures today increasingly consist of “tuneable parts”: parts with a simple geometry described by a small set of strongly varying parameters. For example, although a bridge is a macroscale structure with a complex geometry, it is made from simple beams, bolts and plates, all of which depend on spatially varying, geometrical parameters such as their length-to-width ratio. Accelerating this trend is the concurrent improvement of, on one hand, Additive Manufacturing techniques that allow for increasingly complex parts to be manufactured and, on the other, structural optimization techniques that exploit this expanded design space. However, this trend also poses a challenge to current simulation techniques, as for example the Finite Element Method requires large amounts of elements to represent such structures. We propose to exploit the large conformity between parts inside the mechanical structure through construction of semi-analytic “Parametrized Superelements”, built by meshing with solid elements, reduction to a fixed interface and approximation of the reduced stiffness matrices. These new elements can be employed next to standard elements, enabling the simulation of more complex geometries. The technique we propose is applied to lattice structures and provides a flexible, differentiable, more accurate but still efficient way to simulate their elastic response. A net gain in total computation time occurs after simulating more than twenty lattices. As such, the proposed method enables large-scale parameter exploration and optimization of lattice structures for improved energy absorption, mass and/or stiffness.
      PubDate: 2022-05-07
       
  • An efficient numerical scheme for the FE-approximation of magnetic stray
           fields in infinite domains

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      Abstract: Abstract In this contribution we propose an efficient and simple finite-element procedure for the approximation of open boundary problems for applications in magnetostatics. In these problems, the interaction of the solid with external space plays a crucial role because of the magnetic stray fields that arise. For this purpose, the infinite region under consideration is approximated by a sufficiently large domain. This region is then divided into a so-called interior domain and an exterior domain. As an essential prerequisite, we assume linear behavior of the (large) exterior domain. The latter is then reduced to the degrees of freedom of the connecting line (2D)/connecting surface (3D) of both domains via static condensation. The proposed finite element scheme can be seen as an alternative to established methods for infinite domains. These methods often require semi-analytical solutions to describe the behavior in the exterior domain, which can be difficult to obtain if heterogeneous structures are present. The proposed finite element procedure is not subject to any restrictions with regard to the topology of the exterior space. After a general introduction of the numerical scheme, we apply the method to problems of magnetostatics with nonlinear behavior in the interior domain.
      PubDate: 2022-05-06
       
  • A generalised path-following solver for robust analysis of material
           failure

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      Abstract: Abstract When analysing complex structures with advanced damage or material models, it is important to use a robust solution method in order to trace the full equilibrium path. In light of this, we propose a new path-following solver based on the integral of the rate of dissipation in each material point, for solving problems exhibiting large energy dissipating mechanisms. The method is a generalisation and unification of previously proposed dissipation based path-following solvers, and makes it possible to describe a wider range of dissipation mechanisms, such as large strain plasticity. Furthermore, the proposed method makes it possible to, in a straightforward way, combine the effects from multiple dissipation mechanisms in a simulation. The capabilities of the solver are demonstrated on four numerical examples, from which it can be concluded that the proposed method is both versatile and robust, and can be used in different research domains within computational structural mechanics and material science.
      PubDate: 2022-05-05
       
  • Virtual element method with adaptive refinement for problems of
           two-dimensional complex topology models from an engineering perspective

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      Abstract: Abstract Virtual element methods (VEM) provide great flexibility in solving numerical problems defined on arbitrarily shaped polygonal or polyhedral discretizations. In this paper, we develop a framework for two dimensional elastic problems defined on complex topology models using high-order virtual element methods from an engineering perspective. The VEM discrete formulations are detailedly derived following the rule used in standard FEM. An arbitrarily complex model is first embedded into a rectangular domain which is then discretized into a structured grid. The elements intersecting with the boundaries are further adaptively refined through a quad-tree refinement strategy controlled by a subdivision level or an approximation error. An optimization method is proposed to avoid the generation of tiny elements and two averaged schemes for stress recovery in post-processing are discussed. The behavior of the proposed VEM is thoroughly studied and the results are compared with analytical solutions and that obtained from FEM. The heavy burden placed on meshing complex CAD geometries is greatly alleviated and the convergence studies confirm the accuracy and convergence of the method.
      PubDate: 2022-05-05
       
 
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