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computational framework enabling comparative analysis of progressive damage models for composite materials

Computational framework enabling comparative analysis of pro...

ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2020

作者： Apetre, A. Michopoulos, J.G. Iliopoulos, A.P. Steuben, J.C. Phan, N. Naval Research Laboratory Computational Multiphysics Systems Laboratory Center of Materials Physics and Technology Washington DC20375 United States Structures Division Naval Air Systems Command Patuxent River MD20670 United States

ISBN: (纸本)9780791883945

The present work is motivated by the need for an efficient and quantifiable assessment of how various strain-or stressbased composite materials failure criteria and damage evolution models that capture the load-induced material degradation, along with their intrinsic parameters, can affect our understanding of material behavior and facilitate suitability decisions of such criteria. The difficulty of performing comparative analysis among many of these criteria and models has been a significant impediment to the composite materials design and material certification communities. In response to these needs, the present work describes the development, verification and validation of such a general computational framework. This framework enables not only increasing the user's understanding of the effect of parameters associated with models under consideration on the model predicted results but also allowing the user to address more advanced problems such as material design, optimization and potentially certification. The framework implemented into "COMSOL multiphysics" utilizes symbolic algebra to automatically generate the required expressions to be used in the respective computational modules. Two strain-based models for two distinct specimen geometries are used to show the framework capabilities: One model is described by three damage modes and a second one is given by four damage modes. The first geometry is that of a unnotched coupon whereas the second is that of an open hole specimen in tension. The theoretical predictions are compared with the experimental ones in terms of load-strain responses. The results indicate that by proper selection of specific input parameters, these models can accurately predict the structural response of composite laminate structural systems up to failure. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Failure (mechanical)

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Projection-tree reduced order modeling for fast N-body computations

arXiv

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arXiv 2021年

作者： Rodriguez, Steven N. Iliopoulos, Athanasios P. Carlberg, Kevin T. Brunton, Steven L. Steuben, John C. Michopoulos, John G. Computational Multiphysics Systems Laboratory U. S. Naval Research Laboratory WashingtonDC United States Department of Mechanical Engineering University of Washington SeattleWA United States

This work presents a data-driven reduced-order modeling framework to accelerate the computations of N-body dynamical systems and their pair-wise interactions. The proposed framework differs from traditional acceleration methods, like the Barnes-Hut method, which requires online tree building of the state space, or the fast-multipole method, which requires rigorous a priori analysis of governing kernels and online tree building. Our approach combines Barnes-Hut hierarchical decomposition, dimensional compression via the least-squares Petrov-Galerkin (LSPG) projection, and hyper-reduction by way of the Gauss-Newton with approximated tensor (GNAT) approach. The resulting projection-tree reduced order model (PTROM) enables a drastic reduction in operational count complexity by constructing sparse hyper-reduced pairwise interactions of the N-body dynamical system. As a result, the presented framework is capable of achieving an operational count complexity that is independent of N, the number of bodies in the numerical domain. Capabilities of the PTROM method are demonstrated on the two-dimensional fluid-dynamic Biot-Savart kernel within a parametric and reproductive setting. Results show the PTROM is capable of achieving over 2000× wall-time speed-up with respect to the full-order model, where the speed-up increases with N. The resulting solution delivers quantities of interest with errors that are less than 0.1% with respect to full-order model. Copyright © 2021, The Authors. All rights reserved.

关键词： Dynamical systems

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Coupled electromagnetic and thermoelastic response of conductive materials under mechanical loading and high current pulse conditions 41

Coupled electromagnetic and thermoelastic response of conduc...

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41st Computers and Information in Engineering Conference, CIE 2021, Held as Part of the ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2021

作者： Michopoulos, J.G. Iliopoulos, A.P. Steuben, J.C. Apetre, N.A. Douglass, S. Lynn, A.G. Cairns, R.L. Computational Multiphysics Systems Lab. Code 6394 Center of Materials Physics and Technology U.S. Naval Research Laboratory WashingtonDC20375 United States Plasma Physics Division Code 6752 U.S. Naval Research Laboratory WashingtonDC20375 United States Alion Science and Technology McLeanVA221025 United States

ISBN: (纸本)9780791885376

Understanding, modeling and simulating the behavior of thermally and electrically conductive materials under simultaneous high electric current pulse and mechanical preload conditions has long been a topic of interest for various applications involving electromechanical systems. To this end, the present work describes a computational framework that enables the fully coupled electromagnetic and thermoelastic analysis of such systems. The partial differential equations (PDEs) representing the electrodynamic and thermodynamic conservation laws are utilized and encapsulated in a computational environment enabling their numerical solution. A specific contribution of the framework is that it is capable of solving the non-linear forms of the relevant PDEs that are formed due to the dependence of the material properties on state variables such as temperature. The proposed framework is applied for a specific high-current testing apparatus under construction in our laboratory. A high current pulse is conducted through a mechanically pretensioned specimen and generates Joule heating activating thermo-elastic strains in conjunction with Lorentz body forces influencing the associated dynamic thermo-structural response of specimens of interest. Application of the developed framework enables the generation of field predictions for the quantities of interest. Selective simulation results are presented to demonstrate the capabilities of the proposed framework followed by discussion and conclusions. Copyright © 2021 by The United States Government

关键词： Conductive materials

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Inverse identification of non-linear odes for the dynamic control of material testing systems

Inverse identification of non-linear odes for the dynamic co...

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ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2020

作者： Lunasin, Evelyn M. Iliopoulos, Athanasios P. Michopoulos, John G. Steuben, John C. Department of Mathematics United States Naval Academy AnnapolisMD21402 United States Computational Multiphysics Systems Laboratory Center of Materials Physics and Technology U.S. Naval Research Laboratory WashingtonDC20375 United States

ISBN: (纸本)9780791883983

The development of advanced robotic systems for material testing by the U.S. Naval Research laboratory has expanded the set of requirements for mechatronic system control. This expansion lies beyond the limits of readily available control system capabilities because of the high control rate requirements. To establish this capability, a control mechanism based on the online identification of the ordinary differential equation governing the coupled equations of motion and deformation is proposed in the present work. The part of the proposed approach involving the inverse identification of the ODEs at hand is described in its general form first. Subsequently, the numerical verification is demonstrated via synthetic tests for a compliant actuation system with varying levels of noise injected in the system. Copyright © 2020 ASME.

关键词： Ordinary differential equations

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Investigating the coupled effects between rotor-blade aeroelasticity and tip vortex stability

Investigating the coupled effects between rotor-blade aeroel...

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ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2020

作者： Rodriguez, Steven N. Iliopoulos, Athanasios P. Michopoulos, John G. Jaworski, Justin W. Computational Multiphysics Systems Laboratory Center of Materials Physics and Technology U.S. Naval Research Laboratory WashingtonDC20375 United States Department of Mechanical Engineering and Mechanics Lehigh University BethlehemPA18015 United States

ISBN: (纸本)9780791883983

The relationship between rotor-blade aeroelasticity and tip-vortex stability is investigated numerically. An aeroelastic framework based on the free-vortex wake and finite element methods is employed to model a subscaled helicopter rotor in hover and forward-tilted conditions. A linear eigenvalue stability analysis is performed on tip vortices to associate the coupled impact of aeroelastic effects and vortex evolution. Prior numerical investigations have shown that highly flexible wind turbine rotor-blades have the potential to decrease levels of the instability of tip vortices. The present work focuses on testing these findings against a subscaled rotor within the range of helicopter operational rotation frequencies. The presented work aims to develop further insight into rotor-wake interactions and blade-vortex interaction to explore the mitigation of adverse rotorcraft operational conditions, such as their effect on aerodynamic-induced airframe vibrations and the associated life-cycle fatigue performance. Copyright © 2020 ASME.

关键词： Aeroelasticity

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Determination of the Thermal Conductivity of Gas-Hydrate-Containing Porous Media using Discrete Geometric Analogues

Determination of the Thermal Conductivity of Gas-Hydrate-Con...

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IEEE Region 8 International Conference on computational Technologies in Electrical and Electronics Engineering, SIBIRCON

作者： Sergey I. Markov Ella P. Shurina Natalya B. Itkina Department of Computer Technologies Novosibirsk State Technical University Laboratory of Mathematical Modeling of Multiphysics Phenomena in Native and Artificial Multiscale Heterogeneous Media Trofimuk Institute of Petroleum Geology and Geophysics SB RAS Novosibirsk Russia SB RAS Department of Computer Technologies Laboratory of Analysis and Optimization of Nonlinear Systems Institute of Computational Technologies Novosibirsk State Technical University Novosibirsk Russia

ISBN: (纸本)9781665464819

This work deals with the problem of reconstructing the thermal conductivity coefficient of ice-gas- hydrate rocks. It is proposed to use the results of direct mathematical simulation of heat transfer processes in a heterogeneous porous medium with different phase composition, and the principles of energy conservation law. The results of high-resolution X-ray tomography are applied to construct a digital model of the gas-hydrate-containing medium using machine learning procedure and special thresholding methods. A discrete geometrical model of the digital model is constructed by methods based on adapted symplectic partitions. In contrast to existing solutions to the above problem, our approach is not based on the application of phenomenological reduced models. We apply continuum models of the medium under study, and the heat transfer process. This approach makes it possible to obtain physically relevant results for determining the thermal conductivity coefficient of a heterogeneous medium using its digital analogue. The influence of the phase composition and contrast of the thermal characteristics on the value of thermal conductivity coefficient of ice-gas-hydrate-containing samples is presented.

关键词： Adaptation models computational modeling Thermal engineering Conductivity X-ray tomography Rocks Mathematical models

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Performance signature qualification for additively manufactured parts under conditions emulating in-service loading 3

Performance signature qualification for additively manufactu...

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3rd ASTM Symposium on Structural Integrity of Additive Manufactured Parts

作者： Michopoulos, John G. Steuben, John C. Iliopoulos, Athanasios P. Nguyen, Trung Phan, Nam Computational Multiphysics Systems Lab U.S. Naval Research Laboratory Code 6394 WashingtonDC20375 United States Structures Division Naval Air Systems Command 48110 Shaw Rd. Patuxent RiverMD20670 United States

ISBN: (纸本)9780803176867

The micro- and meso-scale material morphologies generated by additive manufacturing (AM) processes can differ remarkably from those arising from conventional manufacturing (CM) methods. A consequence of this fact is the substandard functional performance of the produced parts that can limit the use of AM in some applications. In the present work, a rapid functional qualification methodology for AM-produced parts is presented. This method is based on a concept defined as absolute and differential performance signature qualification. The concept of performance signature (PerSig) is introduced both as a vector of featured quantities of interest (QoIs) and as a graphic representation in the form of radar or spider graph, representing the QoIs associated with the performance of relevant parts. The PerSigs are defined for both the prequalified CM parts and the AM-produced parts. Comparison measures are defined and enable the construction of differential PerSigs (dPerSig) in a manner that captures the differential performance of the AM part versus the prequalified CM one. The dPerSigs enable AM part qualification based on how their PerSigs are different from those of prequalified CM parts. After defining the steps of the proposed methodology, a description of its application is given for a part of an aircraft landing gear assembly and demonstrate its feasibility for the case of static loads. Furthermore, the extension of this methodology is introduced for a multiaxial loading environment intended to reproduce the proper loading conditions of more complex structures, by using the custom-designed six degrees of freedom testing frames. © 2020 ASTM International.

关键词： 3D printers

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Simulation informed effects of solidification rate on 316l single tracks produced by selective laser melting

Simulation informed effects of solidification rate on 316l s...

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ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2020

作者： Rawlings, A.L.K. Birnbaum, A.J. Michopoulos, J.G. Steuben, J.C. Iliopoulos, A.P. Ryou, H. Computational Multiphysics Systems Laboratory Center of Materials Physics and Technology U.S. Naval Research Laboratory WashingtonDC20375 United States Ceramics and Rapid Prototyping Section Multifunctional Materials Branch U.S. Naval Research Laboratory WashingtonDC20375 United States

ISBN: (纸本)9780791883983

The formation of sub-grain cellular structures generated during the rapid solidification associated with selective laser melting (SLM) typically yields enhanced mechanical properties in terms of yield stress without considerable loss in ductility when compared with those of wrought material. The extent to which the sub-grain structure appears under standard metallographic preparation shows dependence on multiple systematic conditions. This study identifies the effects of solidification and cooling rate on the grain and sub-grain structure in stainless steel through varying the processing parameters (laser power, scan velocity and spot size) of single tracks on both as-received, small grain and annealed, giant grain substrates. The process parameters, in conjunction with the initial substrate microstructure, are key components in understanding the resulting microstructure. Process parameters, particularly scan velocity, dictate the solidification rate and primary regrowth directions while the initial microstructure and its thermomechanical history dictate the propensity for stored strain energy density. Modeling the thermal process allows for experimental analysis within the context of predicted location within processing space as it pertains to local interface velocity and temperature gradient. Furthermore, it highlights the fact that this specific material system behaves in a manner that is inconsistent with classical solidification theory. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Strain energy

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Measuring dielectric properties of ceramic powders at microwave frequencies for material processing applications

Measuring dielectric properties of ceramic powders at microw...

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ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2020

作者： Graber, B.D. Iliopoulos, A.P. Michopoulos, J.G. Steuben, J.C. Birnbaum, A.J. Fischer, R.P. Johnson, L.A. Bernhardt, P.A. Coombs, J.M. Gorzkowski, E.P. Patterson, E.A. Computational Multiphysics Systems Laboratory Center of Materials Physics and Technology Naval Research Laboratory WashingtonDC20375 United States Code 6700 Plasma Physics Division Naval Research Laboratory WashingtonDC20375 United States Code 6351 Multifunctional Materials Branch Naval Research Laboratory WashingtonDC20375 United States

ISBN: (纸本)9780791883983

Ceramic powders are commonly used as precursors for several ceramic part manufacturing processes. Their dielectric characterization is necessary for all the cases where electromagnetic radiation is used to induce heating. In support of such activities at the U.S. Naval Research laboratory, the present work introduces a technique for measuring the complex dielectric constants of ceramic powders at microwave frequencies. The data produced by this technique is critical for the proper modeling of ceramic powder microwave absorption and will assist in ongoing research into volumetric microwave sintering. This technique involves a transmission line measurement using a network analyzer and waveguide setup. Dielectric parameters are then extracted from these measurements using two established methods. Complex relative permittivity measurements are presented for ceramic powders of yttria stabilized zirconia (YSZ), barium titanate (BaTiO3), zinc oxide (ZnO), and titanium dioxide (TiO2) as well as a method for containing the sample shape during measurement. Experiments were carried out between 25 and 40GHz;in the Ka microwave band. Experimental results suggest that the dielectric constant (Ε0) of these powders are similar to those of bulk. Results are compared to lower frequency reference data showing reasonable agreement. Copyright © 2020 ASME.

关键词： Titanium dioxide

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Morphological analysis of 316l laser powder bed fusion melt-pool via the enriched analytical solution method

Morphological analysis of 316l laser powder bed fusion melt-...

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ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2020

作者： Michopoulos, J.G. Steuben, J.C. Birnbaum, A.J. Iliopoulos, A.P. Aroh, J. Rollett, A.D. Gould, B. Computational Multiphysics Systems Laboratory Center of Materials Physics and Technology U.S. Naval Research Laboratory WashingtonDC20375 United States Dpt. of Materials Science and Engineering Carnegie Mellon University PittsburghPA15213 United States Applied Materials Division Argonne National Laboratory ArgonneIL60439 United States

ISBN: (纸本)9780791883983

The recent development of the Enriched Analytical Solution Method (EASM) for evaluating the spatio-temporal distribution of the temperature fields generated during the Laser Powder Bed Fusion (LPBF) Additive Manufacturing (AM) processes is provides an opportunity to study the sensitivity of the morphological parameters characterizing the associated melt-pools as a function of process parameters. The present work exercises the EASM for the case of a single-path trace over a 316L base plate under LPBF heat deposition conditions. To assist in the evaluation of solidification parameters, the spatial derivatives of the EASM are also derived. A process parameter subspace spanned by the scan velocity and the laser power is considered and the EASM is utilized for deriving a number of geometrical morphological characteristics of the melt pool as well as the quantities controlling the evolution of the solidification front. Finally, comparisons with initial experimental results obtained by in-situ high speed synchrotron X-ray imaging, capturing the spatio-temporal evolution of the melt pool profile are also presented. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Solidification

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