bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical investigation of aerosol deposition on a single 2D fiber
Authors: Mohan Saravanan , Chaudhuri Jayotpaul , Gödeke Lutz , Ehrhard Peter 
Published: November 2019

AbstractThe aerosol filtration technique deserves extensive attention, due to its wide applications found in health, environment, and industry. The simulation of aerosol filtration over fibrous filters involves the numerical investigation of the motion and capture of particles (aerosols) under different fluid operating conditions.The capture of aerosol in fibrous filters involves the following deposition mechanisms: Impaction, interception, diffusion and gravitation. The motion of the particles is governed by the relevant forces acting on the particles. Due to the dilute concentration of the aerosol, the influence of particle motion onto the fluid and particle‐particle interaction can be neglected. The particles are removed by a fibrous filter when they collide and stick to the surface of the fiber. An Euler‐Lagrangian approach is engaged to simulate the particle trajectories. The air flow field (continuous phase) is simulated in Ansys CFX (Euler approach) and the particle trajectories (dispersed phase) are computed by Lagrangian simulations in MATLAB.Real fibrous filters consist of a large number of fibers of non‐uniform size and random orientation and position. For simplification, a single 2D fiber is considered and placed normal to the airflow to analyse several deposition mechanisms. The efficiency at which the particles are collected by a single fiber from an aerosol stream is called single‐fiber efficiency EΣ, which is highly dependent on particle size. The particle motion is also affected by diffusion, where the dispersion of particles due to Brownian motion follows a Gaussian distribution. The diffusion coefficient can be inferred from the mean distance travelled by the particle and agrees well with the theoretical diffusion coefficient calculated from the Stokes‐Einstein equation. The diffusion mechanism becomes significant at particle sizes below 0.2 µm. The single‐fiber efficiency is determined considering all deposition mechanisms and compared with existing theoretical models.
A higher order geometrically nonlinear Cosserat‐shell model with initial curvature effects
Authors: Neff Patrizio , Bîrsan Mircea , Ghiba Ionel-Dumitrel 
Published: November 2019

AbstractUsing a geometrically motivated 8‐parameter ansatz through the thickness, we reduce a three‐dimensional shell‐like geometrically nonlinear Cosserat material to a fully two‐dimensional shell model. Curvature effects are fully taken into account. For elastic isotropic Cosserat materials, the integration through the thickness can be performed analytically and a generalized plane stress condition allows for a closed‐form expression of the thickness stretch and the nonsymmetric shift of the midsurface in bending. We obtain an explicit form of the elastic strain energy density for Cosserat shells, including terms up to order O(h5) in the shell thickness h. This energy density is expressed as a quadratic function of the nonlinear elastic shell strain tensor and the bending‐curvature tensor, with coefficients depending on the initial curvature of the shell.
Towards overcoming the bottleneck of optimizing control parameters in finite element active human body models
Authors: Martynenko Oleksandr V. , Stollenmaier Katrin , Endler Carola A. , Neininger Fabian T. , Schmitt Syn , Haeufle Daniel F.B. 
Published: November 2019

AbstractThe number of Finite Element Active Human Body Model (FE aHBM) applications for the design and test of vehicle safety systems is growing. Primarily they are used for simulations of the accident pre‐crash phase where the influence of occupants active movements is significant. Such models are capable of accounting for dynamic human behaviour and reflexes by incorporating bio‐inspired muscle controllers. These controllers need to govern hundreds of active muscle elements during simulation in every time‐step thereby dramatically increasing runtime compared to passive HBMs. As runtime is an essential element of the entire research and development process of a new vehicle, new approaches for its reduction are required. The current contribution presents methods for the tuning of controller and active muscle element parameters using a reduced multibody (MB) model with a subsequent transfer to a fully deformable FE model.
On Osmotic Pressure in Hyperelastic Biphasic Fiber‐Reinforced Articular Cartilage
Authors: Egli Franziska , Ricken Tim 
Published: November 2019

AbstractArticular cartilage belongs to the group of connective tissues and ensures a low‐friction performance of the human musculoskeletal system. It is a complex multiphase material with two main components: a collagen fiber‐reinforced porous solid and a liquid phase. The mechanical behavior of articular cartilage is decisively determined by the interaction between the highly anisotropic, inhomogeneously distributed collagen fiber network, the isotropically distributed proteoglycans and the interstitial fluid. The electrically negatively charged proteoglycans generate an electrical gradient that creates an osmotic negative pressure on the fluid which causes swelling of the cartilage. This leads to mechanically prestressed collagen fibers resulting in a decrease of total pressure occurring inside the cartilage. An increasingly common joint disease is osteoarthritis (OA), which severely impairs everyday life, especially in the elderly population. It is characterized by a loss of matrix stiffness as well as by a reduced tension stiffness and viscoelasticity of the collagen fibers. The aim of the developed model is to describe the previously mentioned material properties of cartilage as precisely as possible. The biphasic model uses the Theory of Porous Media for homogenization and contains an incompressible poroelastic solid matrix reinforced with collagen fibers and an incompressible pore fluid. By including the occurring osmotic pressure, the correct initial stress state of the imaged configuration is considered.
Mean field surrogate model of a dilute and chaotic particle suspension
Authors: Vibe Alexander , Marheineke Nicole 
Published: November 2019

AbstractWe present a mean field approximation for a dilute suspension of small particles, which accounts for a non‐homogeneous particle distribution and small inertial effects of the particle phase. The model consists of the momentum equation for the fluid coupled to a transport equation for the probability density function on the particle phase space. Apart from the well‐known particle extra stress tensor first presented by Batchelor (1970), the fluid equation contains additional force terms resulting from inertia and hydrodynamic interaction of the particles. A brief sketch of the main derivation steps is presented.
Cabin noise prediction using wave‐resolving aircraft models
Authors: Langer Sabine C. , Blech Christopher 
Published: November 2019

AbstractWithin the Coordinated Research Center (CRC) 880, future civil aircraft with short take‐off and landing capabilities are investigated. A main motivation are efficient point‐to‐point connections within Europe. Environmental friendliness is a key factor in the development of such aircraft systems in order to ensure the acceptance of new technologies. Therefore, the sound immission at the ground and in the passenger cabin is a major focus in the project. In this paper, wave‐resolving models of complex aircraft fuselage structures and solution strategies of these large systems in frequency domain are presented.On the basis of preliminary aircraft design data available in the project, a mechanical model of all fluid and structural parts is developed. The model comprises the back partition starting from the wing‐box and assumes a linear behavior in deflection, strain and material. The thickness distribution on the outer surface, the stiffeners, the floor, the bulk heads and the inner panels are considered concerning the structural domain. The insulation is modeled by an equivalent fluid approach. The cabin fluid, the structural domain, and the insulation are fully coupled. All domains are discretized automatically applying coincident nodes at the coupling interfaces. Frequency‐dependent pressure fluctuations distributed on the outer surface as a result of Computational Aeroacoustic (CAA) simulations of jet noise are applied to the model. A realistic consideration of such characteristic noise footprints is only possible due to the wave‐resolving approach. The direct result of the aircraft model is the cabin's pressure field in frequency domain.The finite element discretization leads to a system of equations with 1‐3 mio degrees of freedom to be solved in frequency domain. As one solver run is easily realized, many solutions in the frame of uncertainty analyses or sensitivity studies require a highly efficient solution process. Different strategies applying direct solvers, iterative solvers or its combination are discussed within this contribution as well.
Impact of thin‐walled square aluminum tubes
Authors: Aghdam Nima Jafarzadeh , Tatikonda Uday Bhaskara Chary , Bühring Jannik , Mekala Narasimha Rao , Schröder Kai-Uwe 
Published: November 2019

AbstractThin‐walled profiles are widely used as crash energy absorbers. In this paper thin‐walled square aluminum crash boxes under impact load are studied numerically. ABAQUS commercial software is used for simulating the CBes. The simulated model is validated experimentally using a drop tower test. Folding pattern of a CB has a significant effect on the energy absorption of it. In this study the effects of different parameters such as wall thickness and width on the dynamic behavior and folding pattern of the CB under impact load have been investigated.
Structure‐preserving Galerkin approximation for a class of nonlinear port‐Hamiltonian partial differential equations on networks
Authors: Liljegren-Sailer Björn , Marheineke Nicole 
Published: November 2019

AbstractThe development of structure‐preserving approximation methods, which regard fundamental underlying physical principles, is an active field of research. Especially when the application of model reduction is desirable, systematic and rather generic approaches are of great interest. In this contribution we discuss a structure‐preserving Galerkin approach for a prototypical class of nonlinear partial differential equations on networks. Its derivation is guided by port‐Hamiltonian‐type modeling and appropriate variational principles. Also complexity‐reduction schemes can be integrated in a structure‐preserving way, which becomes crucial in the context of model reduction for nonlinear systems.
Modeling electro‐elastic coupling phenomena in electrostrictive polymers in the context of structural mechanics
Authors: Hansy-Staudigl Elisabeth , Krommer Michael , Vetyukov Yury , Humer Alexander 
Published: November 2019

AbstractBringing into focus the design aspect of thin film electro‐active polymer actuators justifies the deployment of a structural mechanics framework. We propose a physically consistent constitutive model for such actuators, which is valid for plates and shells as material surfaces within a complete direct formulation. To this end, we use the principle of virtual work to deduce the general form of the constitutive law from an augmented Helmholtz free energy, as a function of the structural Green‐Lagrange type strain measures and of the material electric field, without the need of a‐priori assumptions concerning the state of strain and stress.Mechanical deformations of thin film devices – e.g. made of polyurethane – under the action of an external electric field, are caused by two different sources. On the one hand, the applied electric field causes a dielectric polarization of the polymer matrix, yielding to corresponding attractive electrostatic forces between the electroded surfaces resulting into a squeezing of the film. On the other hand, crystalline graft units with a certain natural, but arbitrarily directed polarization, embedded in between the polymer chains, have to align in the direction of the applied electric field such that a rotation of the whole crystal unit takes place. This rotation results in an additional macroscopic thickness squeeze– known as the electrostrictive effect.We treat both electromechanical coupling phenomena separately, where it turns out, that the electrostatic forces can be accounted for by an electrical contribution to the augmented free energy, whereas, the electrostrictive effect is taken into account in the elastic part of the augmented free energy by virtue of a hybrid multiplicative and additive decomposition of the plate/shell deformation measures.Benefiting from the structural mechanics formulation, we gain a lower – two‐dimensional – formulation, which provides a clear physical insight into the nature of the deformation process initiated by the external electric field. E.g. for the linearised problem, a comparison to the literature on thermoelastic plates and shells uncovers the action of the electric field as a combined source of self‐stresses. In order to solve particular problems, the constitutive relation of the geometrically and physically nonlinear formulation is implemented into our in‐house finite element code. The computed results, which were tested against results from the literature as well as against test problems of our previous work (where numerical integration of the three dimensional plate/shell augmented free energy through the thickness was employed), show a very good agreement.
A counterexample for the inf‐sup stability of the RT0 − P1 ⊂ L2(Ω) × H10(Ω) finite element combination for the mixed Poisson equation
Authors: Bertrand Fleurianne , Boffi Daniele 
Published: November 2019

AbstractThis paper investigates the inf‐sup stability of a dual mixed discretization of the Poisson problem using the lowest‐order (Hdiv‐conforming) Raviart–Thomas space combined with the space of standard linear (continuous) Lagrange elements.
An investigation of the heat generated during cyclic loading of ultra‐high performance concrete
Authors: Tran Ngoc Linh , Deutscher Melchior , Scheerer Silke 
Published: November 2019

AbstractIn this paper, the mechanism of heat generation in concrete due to cyclic loading is studied, in which the development of load‐induced temperature is modelled using a heat transfer equation. The heat generation rate is theoretically determined and the calculation is experimentally validated. The influence of the maximum size of aggregate of concrete on the temperature development is also taken into account. It is shown that the load‐induced temperature is generated by conversion of dissipate energy, which mainly occurs at the interfacial transition zone between binders and concrete aggregates and can be described by the plastic work of concrete material.
Simulation of generalized Newtonian fluids with the Smoothed Particle Hydrodynamics method
Authors: Simeunović Miloš , Steeb Holger 
Published: November 2019

AbstractIn this paper we examine Direct Numerical Simulation DNS of single phase non‐Newtonian fluids described by a generalized Newtonian rheology. Non‐Newtonian flow including large deformations and free surface flow could be observed in a wide range of industrial and environmental applications. For that reason, we choose the Lagrangian Smoothed Particle Hydrodynamics (SPH) as a simulation tool. The non‐Newtonian solver is implemented into the general purpose particle framework HOOMD‐blue [1,2], which allows for massive parallel CPU and GPU simulations. Numerical accuracy of the model is demonstrated by simulating confined Poiseuille flow between parallel plates. The validation has been done for a wide variety of shear strain–shear stress ratios where also the effect of the solid‐fluid interface boundary condition is examined. Furthermore, a comparison with the experimental results for the broken dam problem [3] showed good accuracy of the free‐surface flow prediction. Additionally, we have investigated a slump test (Abrams cone [4]), a relatively simple but in practice often performed experiment for non‐Newtonian yield‐stress fluids. Finally, we have investigated in further detail the cone diameter, height, flow time, the final shape and the influence of the rheological model parameters as well as the boundary conditions related to the stationary cone configuration.
Asynchronous time integration in structural mechanics
Authors: Seibold Andreas S. , Rixen Daniel J. 
Published: November 2019

AbstractIn some cases of structural dynamics problems, that are decomposed into substructures, it might be beneficial to have different time‐step‐sizes in each substructure. This is often referred to as asynchronous time‐integration. Since we want to extend our nonlinear FETI‐framework with such an asynchronous time‐integrator in the future, a Lagrange‐multiplier‐based framework should suit us best. As a first step we apply the PASTA‐DDM, which is based on a three‐field‐approach, to a simple linear heterogeneous multi‐mass‐oscillator and investigate the method's energy‐conservation properties. The integration is stable but slightly more energy is dissipated in the asynchronous case than in the synchronous one. Furthermore we solve the global interface‐problem and the local update of Lagrange‐multipliers with a residual‐based conjugate‐gradient method in order to prepare the PASTA‐DDM for an iterative parallel implementation.
Low‐grade fibromyxoid sarcoma: A report of the Cooperative Weichteilsarkom Studiengruppe (CWS)
Authors: Scheer Monika , Vokuhl Christian , Veit‐Friedrich Iris , Münter Marc , von Kalle Thekla , Greulich Michael , Loff Steffan , Stegmaier Sabine , Sparber‐Sauer Monika , Niggli Felix , Ladenstein Ruth , Kazanowska Bernarda , Ljungman Gustaf , Jahnukainen Kirsi , Fuchs Jörg , Bielack Stefan S. , Koscielniak Ewa , Klingebiel Thomas ,   on behalf of the Cooperative Weichteilsarkom Studiengruppe (CWS)
Published: November 2019

ABSTRACTBackgroundLow‐grade fibromyxoid sarcoma (LGFMS) is a rare soft‐tissue tumor with benign histologic appearance, though fully malignant behavior is possible.MethodsPatients with LGFMS <21 years registered in Cooperative Weichteilsarkom Studiengruppe trials until 2017 were analyzed. Firstline treatment consisted of complete surgical resection whenever possible.ResultsMedian age of 31 patients was 10.9 years (first month to 17.1 years). Twenty‐six tumors were confirmed to the tissue of origin (T1), four invaded contiguous structures (T2), one was TX. Eight were >5 cm. The best surgical result was resection with free margins (R0) in 24 and microscopic residuals (R1) in seven. Five‐year event‐free (EFS), 5‐year local‐relapse‐free (LRFS), and 5‐year overall‐survival were 71 ± 18.6% confidence interval (CI) 95%, 76 ± 17.6% CI 95%, and 100%, respectively. Six patients suffered local relapse in a median of 1 year, one combined within 1.3 year and one metastatic relapse with lesions in the lung, back muscles, and thigh discovered in whole‐body imaging 6 years after the first diagnosis. In univariate analysis, T status correlated with EFS (T1 79.6 ± 18.6%, T2 50.0 ± 49.0%, P = .038). Resection with free margins tends to be associated with better LRFS (R0 82.4 ± 18.6%, R1 53.6 ± 39.4%, P = .053). Among 24 patients with R0 resection, five (21%) suffered relapse, thereof three local, one metastatic, and one combined. Among seven patients with R1‐resection, three (43%) suffered local relapse.ConclusionSpecial caution is advisable in T2 tumors. The metastatic potential with lesions in unusual sites indicates that affected patients need to be informed. If long‐term follow‐up with whole‐body imaging is beneficial, it may be addressed in larger intergroup analyses. Further research in disease biology is essential for optimal treatment and follow‐up care.
Neuroblastoma stage 4S: Tumor regression rate and risk factors of progressive disease
Authors: Tas Michelle L. , Nagtegaal Michelle , Kraal Kathelijne C.J.M. , Tytgat Godelieve A.M. , Abeling Nico G.G.M. , Koster Jan , Pluijm Saskia M.F. , Zwaan C. Michel , de Keizer Bart , Molenaar Jan J. , van Noesel Max M. 
Published: November 2019

AbstractBackgroundThe clinical course of neuroblastoma stage 4S or MS is characterized by a high rate of spontaneous tumor regression and favorable outcome. However, the clinical course and rate of the regression are poorly understood.MethodsA retrospective cohort study was performed, including all patients with stage 4S neuroblastoma without MYCN amplification, from two Dutch centers between 1972 and 2012. We investigated the clinical characteristics, the biochemical activity reflected in urinary catecholamine excretion, and radiological imaging to describe the kinetics of tumor regression, therapy response and outcome.ResultsThe cohort of 31 patients reached a 10‐year overall survival of 84% ± 7% (median follow‐up 16 years; range, 3.3‐39). During the regressive phase, liver size normalized in 91% of the patients and catecholamine excretion in 83%, both after a median of two months (liver size: range, 0‐131; catecholamines: range, 0‐158). The primary tumors completely regressed in 69% after 13 months (range, 6‐73), and the liver architecture normalized in 52% after 15 months (range, 5‐131). Antitumor treatment was given in 52% of the patients. Interestingly, regression rates were similar for treated and untreated patients. Four of seven patients < 4 weeks old died of rapid liver expansion and organ compression. Three patients progressed to stage 4, 3 to 13 months after diagnosis; all had persistently elevated catecholamines.ConclusionPatients < 4 weeks old with neuroblastoma stage 4S are at risk of fatal outcome caused by progression of liver metastases. In other patients, tumor regression is characterized by a rapid biochemical normalization that precedes radiological regression.
The genesis of the first specialist PV Bachelor of Engineering program—The educational legacy of Stuart Ross Wenham
Authors: Corkish Richard 
Published: November 2019

AbstractStuart Wenham was not only an outstanding researcher and inventor and mentor but also an outstanding educator. This paper documents some of the major aspects of his educational contributions and legacy, especially through the creation of the first specialised Bachelor of Engineering degree in photovoltaics at The University of New South Wales.
Generalizing Rosenbluth's Algorithm to Include Along‐the‐Chain Intramolecular Energies
Authors: Aldaais Ebtisam A. , Crittenden Scott 
Published: November 2019

ABSTRACTWe incorporate the Boltzmann factors for inter‐monomer bending energy into the monomer growth direction choice in Rosenbluth's algorithm to model chains of arbitrary nearest‐neighbor rigidity. This allows for the consideration of compact (bent state lower in energy), free (straight and bent state equal in energy), or extended chains (bent state higher). We validate against, and compare to, various other results, showing very good agreement with known results for short chains and demonstrate the ability to model chains up to 500 segments long, far beyond the length at which the normal Rosenbluth method becomes unstable for reasonable nonzero bending energies. This approach is easily generalizable both to other energies determinable during chain growth, for example, polymers composed of more than one type of monomer with differing monomer interaction energies, as well as to other chain production algorithms. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1684–1691