The impact of geometric non-linearities on the fatigue analysis of trailing edge bond lines in wind turbine rotor blades

The accurate prediction of stress histories for the fatigue analysis is of utmost importance for the design process of wind turbine rotor blades. As detailed, transient, and geometrically non-linear three-dimensional finite element analyses are computationally weigh too expensive, it is commonly regarded sufficient to calculate the stresses with a geometrically linear analysis and superimpose different stress states in order to obtain the complete stress histories. In order to quantify the error from geometrically linear simulations for the calculation of stress histories and to verify the practical applicability of the superposition principal in fatigue analyses, this paper studies the influence of geometric non-linearity in the example of a trailing edge bond line, as this subcomponent suffers from high strains in span-wise direction. The blade under consideration is that of the IWES IWT-7.5-164 reference wind turbine. From turbine simulations the highest edgewise loading scenario from the fatigue load cases is used as the reference. A 3D finite element model of the blade is created and the bond line fatigue assessment is performed according to the GL certification guidelines in its 2010 edition, and in comparison to the latest DNV GL standard from end of 2015. The results show a significant difference between the geometrically linear and non-linear stress analyses when the bending moments are approximated via a corresponding external loading, especially in case of the 2010 GL certification guidelines. This finding emphasizes the demand to reconsider the application of the superposition principal in fatigue analyses of modern flexible rotor blades, where geometrical nonlinearities become significant. In addition, a new load application methodology is introduced that reduces the geometrically non-linear behaviour of the blade in the finite element analysis.

The plébiscite ; a miller's story of the war by one of the 7,500.000 who voted yes

UANL

Conducta y juicio moral : el proceso de interiorización de normas entre 3 y 7 años.

Elaborar un modelo de desarrollo moral que de cuenta de las relaciones que se establecen entre la valoración moral de una situación y la conducta moral efectiva frente a esa situación, en edades comprendidas entre los 3 y 7 años. La muestra estaba compuesta por 64 sujetos, 32 varones y 32 hembras, alumnos de Párvulos, primero de EGB y segundo de EGB del Colegio Nacional Dolors Monerda de Barcelona, de nivel socio-económico medio y medio-alto. Se analiza el desarrollo moral desde el enfoque psicoanalítico, el enfoque conductista y el enfoque piagetiano. A continuación se analizan y comparan los trazos fundamentales de la conducta moral, en situaciones controladas, de los sujetos de la muestra entre sí y con los resultados obtenidos en un conjunto de 302 fichas recogidas por padres y profesores, en las cuales se detallan conductas morales, en situaciones no sujetas a control, de sujetos de edades comprendidas entre 1 y 12 años. Entrevista personal. Hay relaciones claramente definibles entre el razonamiento acerca de una situación y la acción efectiva sobre ella. En relación a la evolución moral, se definen tres etapas claramente diferenciadas que se manifiestan tanto a nivel de razonamiento como a nivel de conducta.

Occurrence of hiatuses PH and NH 1 through NH 7 in DSDP holes

Miocene paleoceanographic evolution exhibits major changes resulting from the opening and closing of passages, the subsequent changes in oceanic circulation, and development of major Antarctic glaciation. The consequences and timing of these events can be observed in variations in the distribution of deep-sea hiatuses, sedimentation patterns, and biogeographic distribution of planktic organisms. The opening of the Drake Passage in the latest Oligocene to early Miocene (25-20 Ma) resulted in the establishment of the deep circumpolar current, which led to thermal isolation of Antarctica and increased global cooling. This development was associated with a major turnover in planktic organisms, resulting in the evolution of Neogene assemblages and the eventual extinction of Paleogene assemblages. The erosive patterns of two widespread hiatuses (PH, 23.0-22.5 Ma; and NH 1, 20-18 Ma) indicate that a deep circumequatorial circulation existed at this time, characterized by a broad band of carbonate-ooze deposition. Siliceous sedimentation was restricted to the North Atlantic and a narrow band around Antarctica. A major reorganization in deep-sea sedimentation and hiatus distribution patterns occurred near the early/middle Miocene boundary, apparently resulting from changes in oceanic circulation. Beginning at this time, deep-sea erosion occurred throughout the Caribbean (hiatus NH 2, 16-15 Ma), suggesting disruption of the deep circumequatorial circulation and northward deflection of deep currents, and/or intensification of the Gulf Stream. Sediment distribution patterns changed dramatically with the sudden appearance of siliceous-ooze deposition in the marginal and east equatorial North Pacific by 16.0 to 15.5 Ma, coincident with the decline of siliceous sedimentation in the North Atlantic. This silica switch may have been caused by the introduction of Norwegian Overflow Water into the North Atlantic acting as a barrier to outcropping of silica-rich Antarctic Bottom Water. The main aspects of the present oceanic circulation system and sediment distribution pattern were established by 13.5 to 12.5 Ma (hiatus NH 3), coincident with the establishment of a major East Antarctic ice cap. Antarctic glaciation resulted in a broadening belt of siliceous-ooze deposition around Antarctica, increased siliceous sedimentation in the marginal and east equatorial North Pacific and Indian Oceans, and further northward restriction of siliceous sediments in the North Atlantic. Periodic cool climatic events were accompanied by lower eustatic sea levels and widespread deep-sea erosion at 12 to 11 Ma (NH 4), 10 to 9 Ma (NH 5), 7.5 to 6.2 Ma (NH 6), and 5.2 to 4.7 Ma (NH 7).

Klaus Fröhlich-Gildhoff / Stefanie Pietsch / Michael Wünsche / Maike Rönnau-Böse (Hrsg.): Zusammenarbeit mit Eltern, Ein Curriculum für die Aus- und Weiterbildung, (Materialien zur Frühpädagogik Bd. 7) plus CD, Freiburg: Verlag FEL 2011(264 S. [...] [Sammelrezension]

Sammelrezension von: 1. Klaus Fröhlich-Gildhoff / Stefanie Pietsch / Michael Wünsche / Maike Rönnau-Böse (Hrsg.): Zusammenarbeit mit Eltern, Ein Curriculum für die Aus- und Weiterbildung, (Materialien zur Frühpädagogik Bd. 7) plus CD, Freiburg: Verlag FEL 2011 (264 S.; ISBN 978-3-932650-43-3) 2. Susanne Viernickel / Iris Nentwig-Gesemann / Henriette Harms / Sandra Richter / Stefanie Schwarz: Profis für Krippen, Curriculare Bausteine für die Aus- und Weiterbildung frühpädagogischer Fachkräfte, (Materialien zur Frühpädagogik Bd. 8) plus CD, Freiburg: Verlag FEL 2011 (210 S.; ISBN 978-3-932650-44-)