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71.
Sébastien Hentz Laurent Daudeville Frédéric V. Donzé 《Canadian Metallurgical Quarterly》2004,130(6):709-719
The use of a three-dimensional discrete element method (DEM) is proposed to study concrete structures submitted to dynamic loading. The aim of this paper is to validate the model first in the quasistatic domain, and second in dynamic compression, at the sample scale. A particular growing technique is used to set a densely packed assembly of arbitrarily sized spherical particles interacting together, representing concrete. An important difference from classical DEMs where only contact interactions are considered, is the use of an interaction range. First, the correct identification of parameters of the DEM model to simulate elastic and nonlinear deformation including damage and rupture is made through quasistatic uniaxial compression and tension tests. The influence of the packing is shown. The model produces a quantitative match of strength and deformation characteristics of concrete in terms of Young’s modulus, Poisson’s coefficient, and compressive and tensile strengths. Then, its validity is extended through dynamic tests. The simulations exhibit complex macroscopic behaviors of concrete, such as strain softening, fractures that arise from extensive microcracking throughout the assembly, and strain rate dependency. 相似文献
72.
In sheep, recognition of the familiar lamb by the mother depends on the learning of its olfactory signature after parturition. The authors quantified Fos changes in order to identify brain regions activated during lamb odor memory formation. Brain activation was compared with those measured in anosmic ewes displaying maternal behavior but not individual lamb recognition. In intact ewes, parturition induced significant increase in Fos expression in olfactory cortical regions and in cortical amygdala, whereas in anosmic mothers, Fos expression was very low. In contrast, no difference was observed between intact and anosmic ewes in hypothalamic areas and medial amygdala, suggesting a differentiation between the neural network controlling maternal responsiveness and that involved in olfactory lamb memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
73.
G. Gershteyn F. Nürnberger F. Cianciosi N. Shevchenko M. Schaper Fr.‐W. Bach 《国际钢铁研究》2011,82(12):1368-1374
In this work was studied the influence of the plastic deformation's intensity under deep drawing on microstructures of a pearlitic steel containing 0.8% C. Varying the levels of deformation causes diverse dislocation movements as well as modified structural states in the individual phases of the pearlitic eutectoid steel. It is shown that in the course of plastic deformation there is a reduction of interlamellar distance in a pearlite and increase in dislocation density. In some parts partial spheroidisation cementite plates is observed. The bands formed in dislocation structure are found out. The analysis of failure mechanisms of steel with pearlite structure after plastic deformation is carried out. During the deformation of pearlite, the increase in stress at the phase boundary, owing to the elastic strain incompatibility between the ferrite and cementite phases, resembles the stress concentration at grain boundaries. Pores form at the interface between the surface of the ferritic matrix and the spheroidised carbide particles. Such micro pores occur by means of plastic deformation of the ferrite's interstices around the stronger cementite owing to the reduction of the ferritic interstices and their subsequent cracking. 相似文献
74.
Elena Bonetti Giovanna Bonfanti Frédéric Lebon 《Computers & Mathematics with Applications》2019,77(11):2906-2916
In this paper we introduce a model describing a layered structure composed by two thermoelastic adherents and a thin adhesive subject to a degradation process. By an asymptotic expansion method, we derive a model of imperfect interface coupling damage and temperature evolution. Moreover, assuming that the behaviour of the adhesive is ruled by two different regimes, one in traction and one in compression, we derive a second limit model where unilateral contact conditions on the interface are also included. 相似文献
75.
Product development involves many experts collaborating to the same design goal. Every expert has his own formalisms and tools leading to a high heterogeneity of information systems supporting design activities. Interoperability became a major challenge to avoid information incompatibility along the product life cycle. To synchronise heterogeneous representations of product will be a major step to integrate expert activities. In this paper, the authors propose a meta-model framework to connect together heterogeneous design models. This meta-model framework is used to formalise possible interactions between heterogeneous representations. Interaction formalisation is considered as a key point to synchronise heterogeneous models and to provide more interoperability between various computer assisted systems. The synchronisation loop is also presented as a major sequence of activities to manage collaborative design. Tools to support synchronisation are proposed. However, through a basic case study, authors highlight what can be automated and where human intervention is still expected. 相似文献
76.
v. Schröder Karl Boresch K. Dirr R. Ammon Diemair Griebel Schwaibold G. Mall Felicitas Rolleri Kanitz O. Windhausen K. Felix von Querner W. Ludorff E. Fischbach W. Sutthoff Frey-Wyssling Schormüller A. Pirson J. Großfeld E. Chytrek Koelitz Hans Hawelka W. Schreiber Brüning Estler Pawletta W. Wodsak Jesser H. J. Steinbeck Seuss Schmitz Lars Erlandsen W. Hämmerle Masch A. Bäurle W. Leithe Rudolj Abderhalden Haevecker Fr. Bartschat Garber G. Stamm Gertraude Körner-Hennig G. Steinhoff Johannes Wolf Rob Jungkunz Schönfeld Ed. Rentz Klinc K. Höll 《European Food Research and Technology》1940,79(6):568-608
77.
Bames H. J. Steinbeck W. Ludorff G. Mall Schormüller J. Ph. Br. Roßmann A. Lendle Schwaibold Albers W. Schreiber Rudolf Abderhalden Frey-Wyssling Hans Hawelka Bäurle W. Sutthoff Carls Griebel Kanitz Rietschel Griebel G. Stamm Körner-Hennig W. Leithe W. Hämmerle G. Steinhoff W. Wodsak Brüning Estler H. Hofmann Weber Mayser E. E. Bauke O. Windhausen Lars Erlandsen Kluge Kuckuck Haevecker Haevecker E. Dinslage I. Stahn Reichard K. Müller Hanak Kluge K. Höll Fr. Bartschat 《European Food Research and Technology》1940,79(3):272-335
78.
Schormüller J. Großfeld H. Mohler Carls Kanitz Griebel Rudolf Abderhalden W. Schreiber W. Hämmerle Brüning W. Ludorff Pawletta W. Bartels Fr. Bartschat M. Gordienko L. W. Jirak O. Windhausen H. -A. Oelkers I. Stahn J. Ph. Bruno Roßmann Lars Erlandsen Lintzel Flößner Bäurle Reschke Haevecker W. Sutthoff H. Schanderl Masling H. Süllmann v. Noël Reichard E. Dinslage G. Steinhoff Jesser Rob Jungkunz C. Pyriki W. Preiβ K. Müller L. Klinc Zacher Beckel K. Höll 《European Food Research and Technology》1939,78(6):480-496
79.
Schwaibold Schormüller Beckel W. Sutthoff Lars Erlandsen v. Skramlik W. Schreiber Kanitz Bierotte M. Steiner W. Wodsak G. Steinhoff H. J. Steinbeck Frey-Wyssling M. Gordienko K. Dirr Pawletta Stelzer W. Wodsak W. Bartels Hoepke G. Stamm Brüning W. Hämmerle Schnetka K. Felix H. Schülke Kluge Krzywanek W. Brandt Gertraude Körner-Hennig K. J. Demeter Damm J. Ph. Bruno Roßmann W. Karlowa H. Ketterl L. W. Jirak W. Preiß Diemair W. Ludorff Jahr Griebel J. J. van Eck W. Preiß C. Pyriki K. Müller Jesser K. Boresch Fr. Bartschat 《European Food Research and Technology》1939,77(3):290-336
80.
Kanitz O. Windhausen Schwaibold Riffart W. Schreiber Jesser J. J. van Eck Diemair W. Ludorff J. Ph. Bruno Roßmann H. J. Steinbeck Wodsak H. Damm G. Steinhoff L. W. Jirak Fr. Bartschat H. Ketterl J. Großfeld W. Bartels G. Stamm Reichard R. Grau 《European Food Research and Technology》1937,73(5):448-504