scholarly journals Open and closed shear-walls in high-rise structural systems: Static and dynamic analysis

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Alberto Carpinteri ◽  
Giuseppe Lacidogna ◽  
Giuseppe Nitti
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Torsional Rigidity ◽  
Shear Walls ◽  
Mode Shapes ◽  
Structural Systems ◽  
Preliminary Design ◽  
Static And Dynamic Analysis ◽  
High Rise

AbstractIn the present paper, a General Algorithm is applied to the analysis of high-rise structures. This algorithm is to be used as a calculation tool in preliminary design; it allows to define the interaction between closed and open, straight or curved shear-walls, and the forces exchanged in structures subject to mainly horizontal loads. The analysis can be performed in both static and dynamic regimes, the mode shapes and the natural frequencies being assessed. This general formulation allows analyses of high-rise structures by taking into account the torsional rigidity and the warping deformations of the elements composing the building without gross simplifications. In thisway it is possible to model the structure as a single equivalent cantilever, thus minimising the degrees of freedom of the system, and consequently the calculation time. Finally, potentials of the method proposed are demonstrated by a numerical example which emphasizes the link between global displacements and stresses in the elements composing the structure.

scholarly journals An analytical formulation to evaluate natural frequencies and mode shapes of high-rise buildings

2021 ◽  
Vol 8 (1) ◽  
pp. 307-318
Author(s):  
Giuseppe Nitti ◽  
Giuseppe Lacidogna ◽  
Alberto Carpinteri
Keyword(s):  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Shear Walls ◽  
Vertical Axis ◽  
Mode Shapes ◽  
Analytical Formulation ◽  
High Rise ◽  
Open Section ◽  
Stiffness Matrices ◽  
Thin Walled

Abstract In this paper, an original analytical formulation to evaluate the natural frequencies and mode shapes of high-rise buildings is proposed. The methodology is intended to be used by engineers in the preliminary design phases as it allows the evaluation of the dynamic response of high-rise buildings consisting of thin-walled closed- or open-section shear walls, frames, framed tubes, and dia-grid systems. If thin-walled open-section shear walls are present, the stiffness matrix of the element is evaluated considering Vlasov’s theory. Using the procedure called General Algorithm, which allows to assemble the stiffness matrices of the individual vertical bracing elements, it is possible to model the structure as a single equivalent cantilever beam. Furthermore, the degrees of freedom of the structural system are reduced to only three per floor: two translations in the x and y directions and a rigid rotation of the floor around the vertical axis of the building. This results in a drastic reduction in calculation times compared to those necessary to carry out the same analysis using commercial software that implements Finite Element models. The potential of the proposed method is confirmed by a numerical example, which demonstrates the benefits of this procedure.

Analysis of Asymmetric High-Rise Building

2017 ◽  
Vol 738 ◽  
pp. 120-129
Author(s):  
Olga Ivankova ◽  
Marian Stellmach ◽  
Lenka Konecna
Keyword(s):  
Dynamic Analysis ◽  
Soil Structure ◽  
Applied Load ◽  
Soil Structure Interaction ◽  
Static And Dynamic Analysis ◽  
Structure Interaction ◽  
High Rise ◽  
High Rise Building ◽  
Seismic Area ◽  
Two Alternatives

This paper deals with static and dynamic analysis of asymmetric high-rise building. Two alternatives have been analysed – without dilatation and with dilatation. Then, the influence of the dilatation was discussed. The building was located in 4th seismic area in Slovakia (Bratislava). The description of the building, applied load, considered soil-structure interaction, created calculating models, used analysis and obtained results are mentioned here. The conclusions and the photos of defective repairs of real structures are depicted at the end of the paper.

Updating of Non-Conservative Systems Using Inverse Methods

1997 ◽  
Author(s):  
Ladislav Starek ◽  
Milos Musil ◽  
Daniel J. Inman
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Ad Hoc ◽  
Natural Frequencies ◽  
Eigenvalue Problems ◽  
Model Updating ◽  
Analytical Models ◽  
Mode Shapes ◽  
Element Analysis ◽  
Modal Data

Abstract Several incompatibilities exist between analytical models and experimentally obtained data for many systems. In particular finite element analysis (FEA) modeling often produces analytical modal data that does not agree with measured modal data from experimental modal analysis (EMA). These two methods account for the majority of activity in vibration modeling used in industry. The existence of these discrepancies has spanned the discipline of model updating as summarized in the review articles by Inman (1990), Imregun (1991), and Friswell (1995). In this situation the analytical model is characterized by a large number of degrees of freedom (and hence modes), ad hoc damping mechanisms and real eigenvectors (mode shapes). The FEM model produces a mass, damping and stiffness matrix which is numerically solved for modal data consisting of natural frequencies, mode shapes and damping ratios. Common practice is to compare this analytically generated modal data with natural frequencies, mode shapes and damping ratios obtained from EMA. The EMA data is characterized by a small number of modes, incomplete and complex mode shapes and non proportional damping. It is very common in practice for this experimentally obtained modal data to be in minor disagreement with the analytically derived modal data. The point of view taken is that the analytical model is in error and must be refined or corrected based on experimented data. The approach proposed here is to use the results of inverse eigenvalue problems to develop methods for model updating for damped systems. The inverse problem has been addressed by Lancaster and Maroulas (1987), Starek and Inman (1992,1993,1994,1997) and is summarized for undamped systems in the text by Gladwell (1986). There are many sophisticated model updating methods available. The purpose of this paper is to introduce using inverse eigenvalues calculated as a possible approach to solving the model updating problem. The approach is new and as such many of the practical and important issues of noise, incomplete data, etc. are not yet resolved. Hence, the method introduced here is only useful for low order lumped parameter models of the type used for machines rather than structures. In particular, it will be assumed that the entries and geometry of the lumped components is also known.

Influence of the Load-Bearing System of a High-Rise Building on its Stiffness

2015 ◽  
Vol 769 ◽  
pp. 29-35
Author(s):  
Olga Ivankova ◽  
Lenka Konecna
Keyword(s):  
Dynamic Analysis ◽  
Seismic Event ◽  
Short Description ◽  
Load Bearing ◽  
Static And Dynamic Analysis ◽  
High Rise ◽  
Wall System ◽  
Bearing System ◽  
Computing Models ◽  
Storey Building

Static and dynamic analysis of the high-rise (24-storey) building is discussed in this paper. The influence of the change of load-bearing system on its stiffness in the case of seismic event was detected. Two different load-bearing systems were chosen – the wall system (alt.1) and the skeleton system (alt.2). Finite element method was used for the solution of 3D computing models. Short description of the building, used material, applied load, a type of the subsoil and obtained results are mentioned. Dynamic analysis was repeated for four various seismic areas in Slovakia.

Modeling and Free Vibration of Flex Circuits in Hard Disk Drives

2003 ◽  
Author(s):  
Jonathan Wickert
Keyword(s):  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Equilibrium Shape ◽  
Local Equilibrium ◽  
Hard Disk Drives ◽  
Laser Interferometry ◽  
Hard Disk ◽  
System Level ◽  
Mode Shapes ◽  
Free Length

A flex circuit connects the stationary electronic components in a hard disk drive to the rotating arm that carries the read/write heads and positions them above data tracks on the disk. Flex circuits are conventionally formed as a laminate of polyimide substrate, adhesive, and copper conductors. Deformation of a flex circuit is discussed in the context of the following stages: the initial unstressed shape, configurations in which stresses set and relax in response to elevated temperature, equilibrium, and small amplitude vibration. The model involves displacements of the flex circuit in the directions tangent and normal to the local equilibrium shape, and those motions couple with the arm’s dynamics. Nonlinearity associated with finite curvature, partial elastic springback, and the arm’s geometry and inertia properties are incorporated within the vibration model to predict system-level natural frequencies, mode shapes, and coupling factors between the circuit and the arm. Laboratory measurements using noncontact laser interferometry validate the model with respect to the circuit’s shape, stiffness, restoring moment, and natural frequencies. The primary degrees of freedom for optimizing flex circuit design are the thicknesses of the individual layers within the circuit, free length, and the locations and slopes of the circuit’s attachment points to the arm and electronics block. The model’s predictions and trends developed from a case study in free length are discussed with a view toward reducing coupling between the circuit and arm in certain vibration modes.

Dynamic Analysis of an Elevator Traveling Cable Using a Singularity-Free Beam Formulation

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
W. Fan ◽  
W. D. Zhu
Keyword(s):  
Dynamic Analysis ◽  
Multibody Dynamics ◽  
Natural Frequencies ◽  
Vertical Motion ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Out Of Plane ◽  
Forced Responses ◽  
Free Beam ◽  
Good Agreement

A round elevator traveling cable is modeled using a singularity-free beam formulation. Equilibria of the traveling cable with different elevator car positions are studied. Natural frequencies and the corresponding mode shapes of the traveling cable are calculated and they are in excellent agreement with those calculated by abaqus. In-plane natural frequencies of the traveling cable do not change much with the car position compared with its out-of-plane ones. Dynamic responses of the traveling cable are calculated and they are in good agreement with those from commercial multibody dynamics software recurdyn. Effects of vertical motion of the car on free responses of the traveling cable and those of in-plane and out-of-plane building sways on forced responses are investigated.

Third Paper: Dynamic Analysis of an Automobile Chassis Frame

1970 ◽  
Vol 185 (1) ◽  
pp. 683-690 ◽  
Author(s):  
R. Ali ◽  
J. L. Hedges ◽  
B. Mills
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Natural Frequencies ◽  
Experimental Results ◽  
Mode Shapes ◽  
Finite Element Technique ◽  
Inertia Matrix ◽  
Element Technique

The finite element technique has been used for the prediction of natural frequencies and mode shapes of a chassis structure. The program developed in Paper 1 was extended by adding an inertia matrix. The effects of shear and tapered beams were also considered and predictions of frequencies and mode shapes are compared with experimental results.

scholarly journals Dynamic Analysis of Telecommunication Tower for Optimum Modal Combination and Elemental Discretization

2019 ◽  
Vol 9 (1) ◽  
pp. 2229-2237
Keyword(s):  
Dynamic Analysis ◽  
Natural Frequencies ◽  
Response Spectrum ◽  
Continuous System ◽  
Ground Level ◽  
Optimum Number ◽  
Lumped Mass ◽  
Mass System ◽  
Static And Dynamic Analysis ◽  
The Past

Over the past 35 years, the growing demand for wireless and broadcast communication has spurred a dramatic increase in steel telecommunication tower construction and maintenance. Failure of such structures due to severe earthquakes is a major concern. The Indian code suggests the detailed static and dynamic analysis provisions that are to be followed for lumped mass systems like buildings. In case of continuous structures the code only suggests the static analysis provisions in details. But, due to the lack of detailed Indian codal provisions for dynamic analysis of telecommunication tower, a comparative study using response spectrum method is being carried out with the help of suitable software for different ground level conditions in case of India. According to the theoretical approach of any structural dynamics problem, the structures without lumped mass system is considered as continuous system which is further idealized as a series of small elemental segments. Furthermore, the structural analysis of these elemental segments using the concept of Finite Element Method (FEM) is being carried out with the help of the mentioned software and the results of natural frequencies, time periods of the structure are compared to obtain the optimum number of elemental discretization along with the optimum method of modal combination.

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