Range Of Elastic Response Research Articles

GaTe/CdS heterostructure with tunable electronic properties via external electric field and biaxial strain

Abstract This article aims to investigate the electronic properties of GaTe/CdS heterostructure using first-principles calculations based on density functional theory (DFT). A direct band gap of 0.804 eV and type-II band alignment are formed at the GaTe/CdS van der Waals heterobilayer interface, which is beneficial to the spatial effective separation of photogenerated electron–hole pairs. The external electric field can prominently modify the band structure of the GaTe/CdS heterobilayer, occurring indirect-gap to direct-gap and semiconductor to metal transitions under critical electric field. Besides, the biaxial strain also makes a pivotal contribution to the band gap modulation, arising direct-gap to indirect-gap and semiconductor to metal transitions within the range of elastic response. Our results suggest that GaTe/CdS heterostructure is a promising candidate for application in future nanoelectronics and optoelectronics device and also provide some valuable information for future experimental research.

New Proposal for Seismic Rehabilitation of Hospitals in Cuba

This work presents the seismic evaluation and the rehabilitation proposal of one essential facility, specifically the “Guillermo Luis” hospital of the Moa city in Holguin. The authors intend to apply, for the first time, a non-conventional technique used in Cuba to seismic protection of facilities health. This solution is based on seismic energy dissipation mechanisms, by mean of shear link device. The Shear Link-Bozzo device, allows the “GIRON” precast concrete systems to improve the inadequacies of behavior under earthquake lateral load by avoiding the undesired failure mechanism, such as: weak story and torsion due to great stiffness and mass asymmetries. All the above mentioned aspects drive us to take some alternative measures of seismic retrofit for these typical structures, based on the incorporation of the passive energy dissipation that allows the system to behave in the elastic range of response. By means of this solution it is possible to reduce the interference during the rehabilitation works, and also to reduce the time of break services of the hospital.

Battened Steel Columns with Semi-Continuous Base Plate Connections: Experimental Results vs. Theoretical Predictions

The paper describes a comparison of experimental results and theoretical predictions regarding the lateral force-displacement response of built-up battened steel columns including semi-rigid and partial-strength base plate connections. Two specimens, representing samples of columns extracted from an existing industrial building, were fabricated and tested. Different types of both the battens and the base-plate connections characterized the two specimens. Preliminary lateral-loading tests in a range of elastic response, under varying levels of the concomitant axial force, allowed both exploring initial (elastic) stiffness and estimating yield displacements. Subsequently, cyclic lateral-loading tests with a given value of the axial force allowed investigating the restoring force characteristics in case of seismic actions. First, the paper describes and comments on the experimental performance of the two specimens. Second, numerical finite-element model predictions are illustrated and compared with experimental results. Third, based on the experimental results, as well as on the FE model analysis, the study looks for possible extensions and adaptations to current Eurocode 3 prediction models.

Lateral loading tests of built-up battened columns with semi-continuous base-plate connections

The paper describes and discusses results from both physical and numerical tests on lateral-load response of built-up battened steel columns with semi-rigid and partial-strength base-plate connections. Two specimens reproduced different case studies derived from two existing industrial steel buildings designed and built in the 1970s and 1990s respectively. First, multiple monotonic lateral-loading tests were carried out in the elastic range of response by varying the concomitant axial force. Subsequently, each specimen was tested under cyclic lateral-loads in the inelastic range of response for a selected value of the axial force. Following discussion and comparison of physical test results on the two specimens, the paper illustrates finite element (FE) model simulations of the physical tests. Focus of the numerical study is on highlighting modelling uncertainties, which engineering applications should consider in seismic assessment of existing buildings.

11.28: Seismic response of built‐up steel columns with semi‐continuous base‐plate connections: Experimental results vs. theoretical predictions

ABSTRACTThe paper describes a comparison of experimental results and theoretical predictions regarding the lateral force‐displacement response of built‐up steel columns with semi‐continuous (semi‐rigid and partial‐strength) base‐plate connections.Two specimens, representing samples from real columns of an existing industrial building, were fabricated and tested. The columns were both made of two I‐shaped profiles connected by means of battens, but with significant differences in the scheme of battening from one specimen to the other. The base plate connections were also significantly different in the two cases, in terms of local detailing. Preliminary tests were carried out in the elastic range of response, under varying levels of applied axial force. Such elastic tests were used to measure variations of the initial stiffness and corresponding yield displacements with the applied axial force. Subsequently, a cyclic loading test was carried out, per each specimen, to investigate the inelastic response.Initially, the paper describes and comments on the relative performance of the two tested specimens, in terms of stiffness, resistance and ductility, as resulting from the experimental tests.Subsequently, the paper provides theoretical predictions along with a comparison to the experimental results. Firstly, results from finite‐element (FE) models – developed using the Abaqus software – are described. Secondly, results from the application of simplified mechanical models are illustrated. The adopted mechanical models essentially followed the component‐method stipulated by Eurocode 3, but with some adaptations and modifications. The paper finally provides a comparison of experimental results with both numerical and analytical models.

Numerical modeling of dynamic behavior of annular tuned liquid dampers for the application in wind towers under seismic loading

In this study, an innovative technique is introduced for application of annular tuned liquid dampers (ATLD) in wind turbines subjected to seismic ground motions. The performance of ATLD in mitigating the vibration of wind turbines is investigated using numerical simulations. The wind tower is modeled using finite element method while the fluid domain is simulated by finite volume method. The numerical study considers the dynamic behavior of ATLD under different seismic records. Also, the effects of earthquake amplitude and frequency content, structural damping and detuning on the interaction between the tower and ATLD are investigated. The results of time-history analysis show that the ATLD is effective in mitigating the response of a wind turbine when subjected to large-amplitude seismic loading. The wind tower equipped with the proposed ATLD also behaves in the elastic range of response during the considered earthquake records which is critical for the integrity and safety of these structures.

Evaluation of Seismic Performance of Moment Resisting Frames considering Vertical Component of Ground Motion

The design of structures to withstand seismic loading is primarily governed by horizontal ground motion, and the effects of vertical ground motion have long been deemed unimportant or secondary. However, an emerging body of evidence suggests that vertical ground motions have great destructive potential, especially for certain site conditions.Using nonlinear dynamic analyses, the seismic performance of frames is evaluated by simultaneously applying the horizontal and vertical components of earthquake motion. Three special moment frames are subjected to 15 recorded near-field earthquake motions and the results of the analyses are used for performance evaluations, based on FEMA 350 guideline. It is found that, within the elastic range of response, considering the vertical component of ground motion, does not alter the dynamic structural response significantly, however, some tangible differences emerge in nonlinear range of response once the horizontal component of ground motion is accompanied by the vertical component.

Approximations of Lateral Displacements of Reinforced Concrete Frames with Symmetric Haunched Beams in the Elastic Range of Response Using Commercial Software

Commercial software for structural analysis and design has significantly evolved in recent years. Nowadays, they are more user- friendly, in addition to providing engineers with more modeling options to solve complex problems and geometries. Tapered elements in gen- eralandhaunchedbeamsinparticularweretraditionallydifficulttomodelinthepast;therefore,mostcommercialsoftwaredidnotincludethem in their element libraries. Recently, leading commercial software worldwide for structural analysis such as ETABS or STAAD-Pro allow engineerstomodelhaunchedbeamsintheelasticrangeofresponse.However,thetechnicalinformationprovidedwithinthesoftware'smanual does not always describe the details of the numerical modeling; i.e., whether it is based on rigorous traditional methods or is just an approximationbaseduponthecalculusofvariations.InthispapertheapproximationsobtainedwithcommercialsoftwareforasetofRCframes with symmetric haunched beams under lateral loading in the elastic range of response are reported when compared with those obtained with a traditional beam theory in which shear deformations are included. It is shown that the modeling used in commercial software is in general reasonable;however,itleadstoanunderestimationofthelateraldisplacements.Dependingonthesoftwareandthemodelingoptionused,lateral displacementsvaryfrom62toalmost100%ofthosecalculatedusingtraditionalbeamtheory.DOI:10.1061/(ASCE)SC.1943-5576.0000143. © 2013 American Society of Civil Engineers. CE Database subject headings: Beams; Lateral displacement; Computer software; Elasticity. Author keywords: Tapered elements; Haunched beams; Nonprismatic beams.

Determination Of Shear Magnification Factor InBeams And Plates Subjected To Blast Loads

In this paper, the dynamic shear force in beams and plates in the range of elastic response is firstly analysed analytically. Then the widely used simplified analytical method proposed by Biggs [1] for the dynamic shear force is evaluated and its computational accuracy is presented. Finally, the shear magnification factor (SMF) of a beam in the range of elastic response is given analytically, and the effects of the ratio of depth to span and elastic-plastic deformation on the shear force are analysed by the Timoshenko beam theory and nonlinear finite element procedure respectively.

Torsional buckling behaviour of stiffened cylinders under combined loading

In this study cylindrical boundary conditions for finite element analysis are formulated that allow torsional displacement and buckling of a sector of a cylinder of half axial height, and of a circumferential arc angle that will divide into 360°. Finite element tests are carried out on un-stiffened elastic cylinders to verify the method of analysis against classical elastic torsional buckling theory. Elastic–plastic limit point finite element tests are carried out on ring and stringer stiffened and stringer stiffened cylinders to investigate the effects of stiffeners on post-buckling behaviour in torsion. A stringer stiffened cylinder is subjected to many combinations of axial force and surface pressure in the elastic range of response and then tested to failure in torsion to investigate the effects of axial and surface pressure loads on the resistance to plastic collapse in torsion.

Moment redistribution in continuous beams of earthquake resistant multistorey reinforced concrete frames

To allow a more uniform and efficient distribution of load resistance in reinforced concrete frames that may be subjected to seismic excitation well beyond the range of elastic response, the concepts of moment redistribution, well known from the plastic design of steel structures, are re-examined. The aims of moment redistribution, with particular reference to earthquake loading, are stated and relevant terms are defined. To allow advantageous but statically admissible adjustments of moments, derived from an elastic analysis, to be made, the requirements of equilibrium and lateral load resistance are assembled into a set of simple rules. Certain limits for redistribution, which appear to be reasonable in the light of existing provisions for structural ductility, and yet are not too restrictive, are proposed. A technique, involving simple graphic manipulations well suited for design office use, is suggested and with the aid of an example its application is shown in detail.