This paper describes the effect of tool modeling accuracy on the accuracy of springback simulation in sheet metal forming. Simulations of a two-dimensional draw-bending process are carried out by using the polyhedral ...
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This paper describes the effect of tool modeling accuracy on the accuracy of springback simulation in sheet metal forming. Simulations of a two-dimensional draw-bending process are carried out by using the polyhedral tool model and the model whose surface is smoothed by quadratic parametric surfaces proposed by Nagata [1]. It is found that the tool modeling, especially the normal vector accuracy in the present model, plays an important role in the prediction not only of deformation but also of stress distribution. The simulated results show that the tool model based on the so-called Nagata patch enables a more accurate and efficient simulation.
This paper presents the effect of tool modelling accuracy on the simulation accuracy of springback in high strength steels. Simulations of a two‐dimensional draw‐bending process are carried out by using a polyhedral...
This paper presents the effect of tool modelling accuracy on the simulation accuracy of springback in high strength steels. Simulations of a two‐dimensional draw‐bending process are carried out by using a polyhedral tool model whose surface is approximated by a polyhedron, and a model whose surface is smoothed by quadratic parametric surfaces proposed by Nagata [Nagata, Comput. Aided Geom. D, 22(2005), 55–59] (Nagata patch model). It is found that not only the shape accuracy but also the normal vector accuracy of tool models are of importance for accurate springback predictions. The use of the Nagata patch model is an efficient approach not only to improve the simulation accuracy but also to make the simulation be hardly influenced by the tool mesh, even for simulations of a high strength steel in which large amount of springback is involved.
作者：
S. AshhabKoji MaruyamaFranco NoriFrontier Research System
Institute of Physical and Chemical Research (RIKEN) Wako-shi Saitama 351-0198 Japan CREST
Japan Science and Technology Agency Kawaguchi Saitama 332–0012 Japan Physics Department
Michigan Center for Theoretical Physics Applied Physics Program Center for the Study of Complex Systems University of Michigan Ann Arbor Michigan 48109-1040 USA
We discuss the possibility of observing quantum nonlocality using the so-called mode entanglement, analyzing the differences between different types of particles in this context. We first discuss the role of coherent ...
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We discuss the possibility of observing quantum nonlocality using the so-called mode entanglement, analyzing the differences between different types of particles in this context. We first discuss the role of coherent states in such experiments, and we comment on the existence of coherent states in nature. The discussion of coherent states naturally raises questions about the role of particle statistics in this problem. Although the Pauli exclusion principle precludes coherent states with a large number of fermionic particles, we find that a large number of fermionic coherent states, each containing at most one particle, can be used to achieve the same effect as a bosonic coherent state for the purposes of this problem. The discussion of superselection rules arises naturally in this context, because their applicability to a given situation prohibits the use of coherent states. This limitation particularly affects the scenario that we propose for detecting the mode entanglement of fermionic particles.
Summary: In the present work, various surface modifications have been applied to titanium surface. The aim of the modifications was to improve cell adhesion and to determine their influence on the properties of titani...
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Summary: In the present work, various surface modifications have been applied to titanium surface. The aim of the modifications was to improve cell adhesion and to determine their influence on the properties of titanium surface. The unmodified and modified surfaces were observed using SEM. Subtle changes in modified surface layer of titanium samples were examined using the Auger Electron Microanalysis and Photoelectron Spectroscopy. The properties of surfaces were evaluated by contact angle and roughness measurements. The results revealed large differences in morphology of Ti modified with different procedures whereas only minor differences in the chemistry of the surfaces were detected. Preliminary quantitative measurements (cell number, viability and differentiation) of the MG 63 osteoblast-like cells in the direct contact with the surface of the investigated materials show that both the not pre-treated titanium surface and the surfaces modified by the methods used in the this work are all well tolerated by the living cells. Within the experimental scatter all the surfaces provided good substrate for proliferation and growth of the cells.
In this paper we evaluate the enhancement of nonequilibrium concentration fluctuations induced by the Soret effect when a binary fluid layer is subjected to a stationary temperature gradient. Starting from the fluctua...
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In this paper we evaluate the enhancement of nonequilibrium concentration fluctuations induced by the Soret effect when a binary fluid layer is subjected to a stationary temperature gradient. Starting from the fluctuating Boussinesq equations for a binary fluid in the large-Lewis-number approximation, we show how one can obtain an exact expression for the nonequilibrium structure factor in the long-wavelength limit for a fluid layer with realistic impermeable and no-slip boundary conditions. A numerical calculation of the wave-number dependence of the nonequilibrium enhancement and of the corresponding decay rate of the concentration fluctuations is also presented. Some physical consequences of our results are briefly discussed.
Effective attraction between like-charged walls mediated by counterions is studied using local molecular field (LMF) theory. Monte Carlo simulations of the “mimic system” given by LMF theory, with short-ranged “Cou...
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Effective attraction between like-charged walls mediated by counterions is studied using local molecular field (LMF) theory. Monte Carlo simulations of the “mimic system” given by LMF theory, with short-ranged “Coulomb core” interactions in an effective single particle potential incorporating a mean-field average of the long-ranged Coulomb interactions, provide a direct test of the theory, and are in excellent agreement with more complex simulations of the full Coulomb system by Moreira and Netz [Eur. Phys. J. E 8, 33 (2002)]. A simple, generally applicable criterion to determine the consistency parameter σmin needed for accurate use of the LMF theory is presented.
We develop a formalism for single molecule dynamic force spectroscopy to map the energy landscape of protein-protein complex (P1P2). The joint distribution P(τ1,τ2) of unbinding lifetimes τ1 and τ2, measurable in ...
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We develop a formalism for single molecule dynamic force spectroscopy to map the energy landscape of protein-protein complex (P1P2). The joint distribution P(τ1,τ2) of unbinding lifetimes τ1 and τ2, measurable in a compression-tension cycle, which accounts for the internal relaxation dynamics of the proteins under tension, shows that the histogram of τ1 is not Poissonian. The theory is applied to the forced unbinding of protein P1, modeled as a wormlike chain, from P1P2. We propose a new class of experiments which can resolve the effect of internal protein dynamics on the unbinding lifetimes.
We determine the persistence length lp for a bacterial group I ribozyme as a function of concentration of monovalent and divalent cations by fitting the distance distribution functions P(r) obtained from small angle x...
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We determine the persistence length lp for a bacterial group I ribozyme as a function of concentration of monovalent and divalent cations by fitting the distance distribution functions P(r) obtained from small angle x-ray scattering intensity data to the asymptotic form of the calculated PWLC(r) for a wormlike chain. The lp values change dramatically over a narrow range of Mg2+ concentration from ∼21 Å in the unfolded state (U) to ∼10 Å in the compact (IC) and native states. Variations in lp with increasing Na+ concentration are more gradual. In accord with the predictions of polyelectrolyte theory we find lp∝1/κ2 where κ is the inverse Debye-screening length.
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