The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Barbara Rossi - One of the best experts on this subject based on the ideXlab platform.
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shear buckling of stainless steel plate girders with non rigid end posts
Journal of Constructional Steel Research, 2020Co-Authors: Maarten Fortan, Goncalo Ferraz, Kathleen Lauwens, Tom Molkens, Barbara RossiAbstract:Abstract This paper presents an experimental and numerical study of stainless steel plate girders with non-rigid end posts. Stereo vision digital image correlation was employed to continuously measure the Deformed Shape and the corresponding three-dimensional displacements of the lean duplex specimen, which enabled the full deformation history of the whole web of the plate girder to be traced. Following the experimental investigation, a finite element study was conducted and validated. Subsequently, a sensitivity analysis was performed to investigate the effectiveness of all design parameters in order to give directions for improvement. The comparisons showed that the European code leads to acceptable strength predictions, yet further improvements remain possible to more accurately predict the contribution of the flange, and to include the contribution of the stiffness of the non-rigid end post to this instability phenomenon.
M. Minervino - One of the best experts on this subject based on the ideXlab platform.
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The Deformed Shape of isotropic and orthotropic plates subjected to bending moments distributed along the edges
Meccanica, 2014Co-Authors: M. Gigliotti, M. MinervinoAbstract:The paper focuses on the deformation behaviour of isotropic and orthotropic plates subjected to bending moments distributed along the edges, two couples M_0 and −M_0 along the longitudinal and the transverse direction, respectively. It can be experimentally noted that the Deformed Shape of the plate tends to be a saddle for low values of M_0 and cylindrical for high values of M_0. The linear Kirchhoff plate model predicts ‘saddle-Shaped’ deformations for all values of M_0. A model based on energy minimisation and taking into account geometrical nonlinearities is capable to predict the transition from a Deformed Shape to another: the phenomenon is affected by the plate length-to-width ratio (aspect ratio) and by material anisotropy. These effects are explored throughout the paper.
Branko Glisic - One of the best experts on this subject based on the ideXlab platform.
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determining the Deformed Shape of beams using the conjugate beam method and strain measurements
Structural Health Monitoring-an International Journal, 2017Co-Authors: Corrie Kavanaugh, Branko GlisicAbstract:Determining the Deformed Shape of a structure is an important aim of Structural Health Monitoring (SHM), as it can indicate damage or abnormalities in the behavior of structures. Moreover, the Deformed Shape is a parameter that is present in all beamlike structures. The Deformed Shape can be described as the Shape of the centroid line of the structure after deformation, and is a result of loading patterns on the beam. Currently, options for determining the Deformed Shape of the structure include direct external measurement, for example, with radar, lasers, camera imaging, or GPS, or by indirect derivation from internally measureable parameters, such as strain and curvature. Accurate direct long-term monitoring is frequently difficult to achieve mainly due to the effects of environmental factors. Certain indirect methods of analyzing the Deformed Shape, such as the double integration of curvature, require specific knowledge of a structure’s boundary conditions. This paper applies and analyzes another indirect monitoring technique for determining the Deformed Shape: the conjugate beam method. The main aim of this study is to evaluate the errors in using the conjugate beam method for determining the Deformed Shape. The error in this method depends upon the loading configuration, curvature magnitude, and quantity of sensors on the structure. Finally, the conjugate beam method is validated using laboratory test data and data collected from a real structure.
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error in the determination of the Deformed Shape of prismatic beams using the double integration of curvature
Smart Materials and Structures, 2017Co-Authors: Dorotea Sigurdardottir, Jett Stearns, Branko GlisicAbstract:The Deformed Shape is a consequence of loading the structure and it is defined by the Shape of the centroid line of the beam after deformation. The Deformed Shape is a universal parameter of beam-like structures. It is correlated with the curvature of the cross-section; therefore, any unusual behavior that affects the curvature is reflected through the Deformed Shape. Excessive deformations cause user discomfort, damage to adjacent structural members, and may ultimately lead to issues in structural safety. However, direct long-term monitoring of the Deformed Shape in real-life settings is challenging, and an alternative is indirect determination of the Deformed Shape based on curvature monitoring. The challenge of the latter is an accurate evaluation of error in the Deformed Shape determination, which is directly correlated with the number of sensors needed to achieve the desired accuracy. The aim of this paper is to study the Deformed Shape evaluated by numerical double integration of the monitored curvature distribution along the beam, and create a method to predict the associated errors and suggest the number of sensors needed to achieve the desired accuracy. The error due to the accuracy in the curvature measurement is evaluated within the scope of this work. Additionally, the error due to the numerical integration is evaluated. This error depends on the load case (i.e., the Shape of the curvature diagram), the magnitude of curvature, and the density of the sensor network. The method is tested on a laboratory specimen and a real structure. In a laboratory setting, the double integration is in excellent agreement with the beam theory solution which was within the predicted error limits of the numerical integration. Consistent results are also achieved on a real structure—Streicker Bridge on Princeton University campus.
Anand Jagota - One of the best experts on this subject based on the ideXlab platform.
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solid surface tension measured by a liquid drop under a solid film
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Nichole Nadermann, Chungyuen Hui, Anand JagotaAbstract:We show that a drop of liquid a few hundred microns in diameter placed under a solid, elastic, thin film (∼10 μm thick) causes it to bulge by tens of microns. The Deformed Shape is governed by equilibrium of tensions exerted by the various interfaces and the solid film, a form of Neumann’s triangle. Unlike Young’s equation, which specifies the contact angles at the junction of two fluids and a (rigid) solid, and is fundamentally underdetermined, both tensions in the solid film can be determined here if the liquid–vapor surface tension is known independently. Tensions in the solid film have a contribution from elastic stretch and a constant residual component. The residual component, extracted by extrapolation to films of vanishing thickness and supported by analysis of the elastic deformation, is interpreted as the solid–fluid surface tension, demonstrating that compliant thin-film structures can be used to measure solid surface tensions.
Mauricio Gamboamarrufo - One of the best experts on this subject based on the ideXlab platform.
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Deformed Shape wind analysis of tensile membrane structures
Journal of Structural Engineering-asce, 2016Co-Authors: Krisztian Hincz, Mauricio GamboamarrufoAbstract:AbstractConventionally, the pressure coefficients of tensile membrane structures are determined in wind tunnels on rigid models and the effect of the typically large deformations of the membranes on the pressure coefficients is not taken into account. The aim of the current research is to analyze the effect of the displacements of membrane structures on the pressure coefficients. A more precise wind analysis is introduced in this paper. Two rigid models were analyzed in a wind tunnel: the model of the unloaded construction Shape, and the model of the Deformed Shape of the membrane under wind loads. The Deformed Shape was determined with the dynamic relaxation method on the basis of the pressure coefficients obtained from the construction Shape subjected to wind loads. The two pressure coefficient fields, the corresponding membrane stresses and displacements are introduced and compared in this paper. Results show that the displacements of the membrane under wind load can result in significant differences o...