Nonlinear analysis of beams, plane frames and arch using a dierent co-rotating beam element

En este trabajo se describe la formulación corrotacional de un elemento de viga que utiliza distintas teorías, Euler-Bernoulli, Timoshenko y Euler-Bernoulli incluyendo el acoplamiento entre los efectos de los esfuerzos de flexión y axil lo que genera coeficientes no lineales en la matriz de rigidez elástica de dicho elemento. La cinemática corrotacional se basa en la separación del movimiento de un sólido en una parte deformacional y otra en movimiento de cuerpo rígido. La parte deformacional del movimiento es representada por tres grados de libertad: una traslación debido al esfuerzo axil y por las rotaciones nodales debidas a la flexión del elemento. A nivel local se obtienen los esfuerzos internos mediante el princípio de los trabajos virtuales una vez definidas las funciones de interporlación que describen el movimiento deformacional para cada teoría de viga utilizada. Se describe de forma detallada la obtención de las matrices de rigideces elástica para los tres tipos de elementos de viga. A través de algunos ejemplos numéricos se muestra la habilidad del elemento para obtener el comportamiento no lineal de vigas, pórticos y arcos.The present work uses a co-rotating approach for obtain the internal forces and tangent stiffness matrices for three plane beam elements. All of them are based on the same co-rotational approach, and differ by the strain definition used in the local co-rotational coordinate system. Based on the Bernoulli assumption, the first two elements use a linear and a shallow arch strain definition, respectively. The third element is based on the Timoshenko assumption with linear interpolations for the displacements. Some examples are presented and the numerical results demonstrate that the beam elements here presented are able to perform the nonlinear analysis of plane frames and 2D arches and to handle large rotations too.Peer Reviewe

Nonlinear analysis of plane frames using a co-rotating Timoshenko beam element

En este trabajo se describe la formulación corrotacional de un elemento de viga unificado que integra las teorías de vigas de Euler-Bernoulli y de Timoshenko y que no presenta bloqueo por deformación a cortante. La cinemática corrotacional se basa en la separación del movimiento de un sólido en una parte deformacional, y la otra, en movimiento de cuerpo rígido. La parte deformacional del movimiento es representada por tres modos de deformaciones naturales que son generados por el esfuerzo axil, la flexíon pura y la flexíon simple, respectivamente. Los esfuerzos generados por los modos naturales de deformación son auto-equilibrados lo que posibilita la obtención de la matriz de rigidez tangente corrotacional consistente. Se describe de forma detallada la obtención de las matrices de rigideces elástica, geométrica y corrotacional. A través de algunos ejemplos numéricos se muestra la habilidad del elemento de tratar con grandes rotaciones de cuerpo rígido.The present work describes a co-rotating shear flexible beam element without shear locking and integrating Euler-Bernoullis and Timoshenkos beam theories. The co-rotational kinematics is based on the separation of the motion in deformational and rigid body components. The deformation of the beam element is composed by three natural modes of deformation: the extension mode, the symmetric bending mode, and the anti-symmetric bending mode. The respective generalized stresses from these natural modes are self-balanced allowing the achievement of a consistent tangent stiffness matrix. In this paper, it is detailed and deduced all the algebraic steps for the deduction of the elastic stiffness matrix, the geometric stiffness matrix, and the co-rotation stiffness matrix. Some examples are presented and the numerical results demonstrate that the beam element here presented is able to handle large rotations.Peer Reviewe

Application Of Prediction Models Of Asian Soybean Rust In Two Crop Seasons, In Londrina, Pr

Predictive models of Asian soybean rust have been described by researchers to estimate favorable responses to epidemics. The prediction strategies are based on weather data obtained during period when initial symptoms of the disease are observed. Therefore, this study will evaluate the application of two prediction models of Asian soybean rust, and compare the results from two harvest seasons. The experiments were carried out during the 2011/2012 and 2012/2013 seasons in Londrina, PR. "SIGA spore traps" were installed to monitor the presence of Phakopsora pachyrhizi uredospores, and "Electronic trees," to collect data on weather variables. Following the detection of the first urediniospores, incidence and disease severity were assessed and compared with the predictions made by the models. The model described by Reis et al. (2004) did not indicate favorable conditions for the development of the first rust lesions following the detection of the first urediniospores during the 2011/2012 season. The premonitory symptoms of rust in the first and second harvest seasons were observed only when the model of Reis et al. (2004) indicated SDVPI close to 15 units. The model of Del Ponte et al. (2006b) overestimated the final rust severity during the two seasons.3752881288

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

Study of Inclusive J/psi Production in Two-Photon Collisions at LEP II with the DELPHI Detector

Inclusive J/psi production in photon-photon collisions has been observed at LEP II beam energies. A clear signal from the reaction gamma gamma -> J/psi+X is seen. The number of observed N(J/psi -> mu+mu-) events is 36 +/- 7 for an integrated luminosity of 617 pb^{-1}, yielding a cross-section of sigma(J/psi+X) = 45 +/- 9 (stat) +/- 17 (syst) pb. Based on a study of the event shapes of different types of gamma gamma processes in the PYTHIA program, we conclude that (74 +/- 22)% of the observed J/psi events are due to `resolved' photons, the dominant contribution of which is most probably due to the gluon content of the photon.Comment: 13 pages, 8 figures, Accepted by Phys. Lett.

Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions

We study the beam-energy and system-size dependence of \phi meson production (using the hadronic decay mode \phi -- K+K-) by comparing the new results from Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the transverse momentum distributions for \phi mesons are observed to be similar in yield and shape for Cu+Cu and Au+Au colliding systems with similar average numbers of participating nucleons. The \phi meson yields in nucleus-nucleus collisions, normalised by the average number of participating nucleons, are found to be enhanced relative to those from p+p collisions with a different trend compared to strange baryons. The enhancement for \phi mesons is observed to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.Comment: 20 pages and 5 figure

Search for composite and exotic fermions at LEP 2

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio