Prediction of structural responses induced by single-person jumping through a physical principle based on transfer functions

2021 ◽  
pp. 136943322110463
Author(s):  
Haoqi Wang ◽  
Zhuoran Zhang ◽  
Jun Chen
Keyword(s):  
Transfer Functions ◽  
Dynamic Properties ◽  
Structural Response ◽  
Physical Principle ◽  
Design Stage ◽  
Structural Dynamic ◽  
Human System ◽  
System Parameters ◽  
Large Span ◽  
Structural Responses

The vibration caused by human excitation has become a key factor at the structural design stage of large-span structures including footbridges, sport stadia, and high-rise buildings. As the structures tend to become slenderer and lighter, the mass of the crowd is not negligibly small compared with the mass of the structure. In such cases, the crowd and the structure form a coupling system through a mechanism known as human–structure interaction (HSI). Researchers found that the structural responses with and without HSI are different. However, the interaction effect on the structural responses has rarely been quantitatively evaluated from the perspective of human system parameters. In this paper, a novel method using a physical principle to predict jumping-induced structural responses is proposed, in which the structural response is expressed as the multiplication of a series of transfer functions representing human system and structural dynamic properties. Structural responses of a large-span concrete structure under jumping excitation are predicted using the proposed method and identified human system parameters. Comparison with measured responses shows satisfactory agreement. The proposed method provides a solution to consider HSI effect on the calculation of structural responses in the vibration serviceability design for large-span structures.

Extreme Structural Dynamic Response of a Spar Type Wind Turbine

2010 ◽  
Author(s):  
Madjid Karimirad ◽  
Torgeir Moan
Keyword(s):  
Wind Turbine ◽  
Fatigue Limit ◽  
Limit State ◽  
Structural Response ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Average Wind Speed ◽  
Structural Dynamic ◽  
Structural Responses ◽  
Highly Correlated

Proper performance of structures requires among other things that its failure probability is sufficiently small. This would imply design for survival in extreme conditions. The failure of a system can occur when the ultimate strength is exceeded (Ultimate Limit State) or fatigue limit (Fatigue Limit State) is passed. The focus in this paper is on the determination of extreme responses for ULS design checks. The present paper deals with coupled wave and wind induced motion and structural response in harsh condition up to 14.4 (m) significant wave height and 49 (m/sec) 10-min average wind speed (at top of tower, 90 m) for a parked floating wind turbine. In survival condition the wind induced resonant responses (mainly platform pitch resonance) are dominant. Due to platform resonant motion responses, the structural responses are close to Gaussian. The dynamic structural responses show that the process is wide banded. The critical structural responses are determined by coupled aero-hydro-elastic time domain simulation. Based on different simulations (20 1-hour, 20 2-hours, 20 3-hours and 20 5-hours) the mean up-crossing rate has been found in order to predict the extreme structural responses. The most probable maximum of the bending moment and the bending moment having up-crossing rate of 10−4 are found to be close in the present research. The minimum total simulation time in order to get accurate results is highly correlated to the needed up-crossing rate. The 1-hour and 2-hours original values cannot provide any information for 10−4 up-crossing rate. Comparison of different simulation periods shows that the 20 1-hour simulations can be used in order to investigate the 3-hours extreme bending moment if the proper extrapolation of up-crossing rate used.

scholarly journals An analytical method to assess the structural responses of ship side structures by raked bow under oblique collision scenarios

2020 ◽  
pp. 147509022098027
Author(s):  
Zeping Wang ◽  
Kun Liu ◽  
Gang Chen ◽  
Zhiqiang Hu
Keyword(s):  
Numerical Simulations ◽  
Analytical Method ◽  
Structural Damage ◽  
Structural Response ◽  
Design Stage ◽  
Shipping Industry ◽  
Oblique Collision ◽  
Finite Element Software ◽  
Hull Structure ◽  
Structural Responses

With the development of the shipping industry, the number of ships at sea has increased significantly. According to the statistical data, oblique ship collisions are much more frequently happened than that of head-on ship collisions. However, there are less researches on oblique ship collisions than those of head-on ship collisions. The responses of hull structure during oblique collision scenarios are different from those in head-on collision scenarios, and might have wider structural damages, which demonstrate the significance of research on oblique collision scenarios and structural damage. In this paper, the oblique collision scenarios are firstly investigated through numerical simulations. Finite element software LS_DYNA is used for the numerical simulations. Six typical oblique collision scenarios are defined, on purpose of finding the main deformation characteristics of the struck ship. Two basic assumptions were made accordingly. Then, a simplified analytical method is proposed to predict the structural response of ship side structures by raked bow under oblique collision scenarios. The new analytical method includes the deformation mechanism of the side plating, the web girder and the transverse frame. The resistance and energy dissipation of these components are used in an integrated way to evaluate the overall crashworthiness of the side structure of the struck ship. The numerical simulation results match well with the results of analytical calculations, which validates the accuracy of the proposed analytical method. The proposed analytical method can provide an effective way to evaluate the structural crashworthiness of ship side structures in oblique collision scenarios during the structural design stage.

Measured natural periods of concrete shear wall buildings: insights for the design of Canadian buildings

2012 ◽  
Vol 39 (8) ◽  
pp. 867-877 ◽  
Author(s):  
Damien Gilles ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Shear Wall ◽  
Mode Shapes ◽  
Design Stage ◽  
Base Shear ◽  
Period Equation ◽  
Input Load ◽  
Structural Engineers

Structural engineers routinely use rational dynamic analysis methods for the seismic analysis of buildings. In linear analysis based on modal superposition or response spectrum approaches, the overall response of a structure (for instance, base shear or inter-storey drift) is obtained by combining the responses in several vibration modes. These modal responses depend on the input load, but also on the dynamic characteristics of the building, such as its natural periods, mode shapes, and damping. At the design stage, engineers can only predict the natural periods using eigenvalue analysis of structural models or empirical equations provided in building codes. However, once a building is constructed, it is possible to measure more precisely its dynamic properties using a variety of in situ dynamic tests. In this paper, we use ambient motions recorded in 27 reinforced concrete shear wall (RCSW) buildings in Montréal to examine how various empirical models to predict the natural periods of RCSW buildings compare to the periods measured in actual buildings under ambient loading conditions. We show that a model in which the fundamental period of RCSW buildings varies linearly with building height would be a significant improvement over the period equation proposed in the 2010 National Building Code of Canada. Models to predict the natural periods of the first two torsion modes and second sway modes are also presented, along with their uncertainty.

OMA Study on the Structural Dynamic Properties of a Launcher Vehicle Using Flight Data

2017 ◽  
Author(s):  
Marco Eugeni ◽  
Giuliano Coppotelli ◽  
Franco Mastroddi ◽  
Paolo Gaudenzi ◽  
Stephan Muller ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Structural Dynamic ◽  
Flight Data

Іmprovement of driving-speed properties improvement of the method for selecting the parameters of the motor-transmission unit car

2021 ◽  
Vol 13 (1) ◽  
pp. 111-117
Author(s):  
Mikhail Podrigalo ◽  
◽  
Volodymyr Krasnokutskyi ◽  
Vitaliy Kashkanov ◽  
Olexander Tkachenko ◽  
...  
Keyword(s):  
Aerodynamic Drag ◽  
Dynamic Properties ◽  
Aerodynamic Characteristics ◽  
Gear Ratio ◽  
Design Stage ◽  
Transmission Unit ◽  
Air Resistance ◽  
Design Speed ◽  
Maximum Design ◽  
Engine Power

Aerodynamic characteristics have a major impact on the energy efficiency and traction and speed properties of the vehicle. In this article, based on previous studies of the aerodynamic characteristics of various car models, we propose an improved method for selecting engine and transmission parameters at the design stage. The aim of the study is to improve the dynamic properties of the car by improving the method of selecting the main parameters of the engine-transmission unit by refining the calculation of aerodynamic drag. To achieve it, the following tasks must be solved: to specify the method of selecting the maximum effective engine power; to specify a technique of definition of the maximum constructive speed of the car; to develop a technique for selecting gear ratios. The aerodynamic resistance to the movement of the vehicle is determined by the frontal coefficient of the specified resistance, the density of the air, the area of the frontal resistance and the speed of the vehicle. It is known from classical works on the aerodynamics of a car that in the range of vehicle speeds from 20 m / s to 80 m / s, taking the law of squares when assessing the force of air resistance, it is necessary to change the coefficient of frontal aerodynamic drag depending on the speed of the car. However, when carrying out calculations, this coefficient is taken constant, which leads to obtaining large values of the air resistance force at high speeds and lower at low speeds. There are two possible ways to improve the dynamic properties and energy efficiency of the car during its modernization (increasing the maximum design speed of the car by reducing the gear ratio in higher gear; reducing the maximum efficiency of the engine while maintaining the previous gear ratio in higher gear). As a result of the study, the method of selection (maximum effective engine power; maximum design speed of the car; gear ratios) at the design stage of the parameters of the motor-transmission unit of the car has been improved.

Structural dynamic properties of pentahaptocyclopentadienylmetal dicarbonyl dimers

1972 ◽  
Vol 11 (4) ◽  
pp. 671-676 ◽  
Author(s):  
J. G. Bullitt ◽  
F. A. Cotton ◽  
T. J. Marks
Keyword(s):  
Dynamic Properties ◽  
Structural Dynamic

scholarly journals Dynamic control of maximal ventricular elastance via the baroreflex and force-frequency relation in awake dogs before and after pacing-induced heart failure

2010 ◽  
Vol 299 (1) ◽  
pp. H62-H69 ◽  
Author(s):  
Xiaoxiao Chen ◽  
Javier A. Sala-Mercado ◽  
Robert L. Hammond ◽  
Masashi Ichinose ◽  
Soroor Soltani ◽  
...  
Keyword(s):  
Heart Failure ◽  
Transfer Function ◽  
Transfer Functions ◽  
Dynamic Properties ◽  
System Response ◽  
Force Frequency ◽  
Arterial Baroreflex ◽  
Ventricular Elastance ◽  
Arterial Blood ◽  
Frequency Relation

We investigated to what extent maximal ventricular elastance ( Emax) is dynamically controlled by the arterial baroreflex and force-frequency relation in conscious dogs and to what extent these mechanisms are attenuated after the induction of heart failure (HF). We mathematically analyzed spontaneous beat-to-beat hemodynamic variability. First, we estimated Emax for each beat during a baseline period using the ventricular unstressed volume determined with the traditional multiple beat method during vena cava occlusion. We then jointly identified the transfer functions (system gain value and time delay per frequency) relating beat-to-beat fluctuations in arterial blood pressure (ABP) to Emax (ABP→ Emax) and beat-to-beat fluctuations in heart rate (HR) to Emax (HR→ Emax) to characterize the dynamic properties of the arterial baroreflex and force-frequency relation, respectively. During the control condition, the ABP→ Emax transfer function revealed that ABP perturbations caused opposite direction Emax changes with a gain value of −0.023 ± 0.012 ml−1, whereas the HR→ Emax transfer function indicated that HR alterations caused same direction Emax changes with a gain value of 0.013 ± 0.005 mmHg·ml−1·(beats/min)−1. Both transfer functions behaved as low-pass filters. However, the ABP→ Emax transfer function was more sluggish than the HR→ Emax transfer function with overall time constants (indicator of full system response time to a sudden input change) of 11.2 ± 2.8 and 1.7 ± 0.5 s ( P < 0.05), respectively. During the HF condition, the ABP→ Emax and HR→ Emax transfer functions were markedly depressed with gain values reduced to −0.0002 ± 0.007 ml−1 and −0.001 ± 0.004 mmHg·ml−1·(beats/min)−1 ( P < 0.1). Emax is rapidly and significantly controlled at rest, but this modulation is virtually abolished in HF.

scholarly journals Designing a ship course controller by applying the adaptive backstepping method

2012 ◽  
Vol 22 (4) ◽  
pp. 985-997 ◽  
Author(s):  
Anna Witkowska ◽  
Roman Śmierzchalski
Keyword(s):  
Time Domain ◽  
System Performance ◽  
Control Algorithm ◽  
Control Structure ◽  
Dynamic Properties ◽  
Time Domain Analysis ◽  
Design Stage ◽  
Backstepping Method ◽  
Adaptive Backstepping ◽  
Nonlinear Static

The article discusses the problem of designing a proper and efficient adaptive course-keeping control system for a seagoing ship based on the adaptive backstepping method. The proposed controller in the design stage takes into account the dynamic properties of the steering gear and the full nonlinear static maneuvering characteristic. The adjustable parameters of the achieved nonlinear control structure were tuned up by using the genetic algorithm in order to optimize the system performance. A realistic full-scale simulation model of the B-481 type vessel including wave and wind effects was applied to simulate the control algorithm by using time domain analysis.

scholarly journals Approach to Stochastic Modeling of Power Systems

2010 ◽  
Vol 26 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Alexander Rubtsov
Keyword(s):  
Power Systems ◽  
Power System ◽  
Stochastic Modeling ◽  
Transfer Functions ◽  
Dynamic Properties ◽  
Stochastic Disturbance ◽  
Modeling Power ◽  
Linearized Model ◽  
System Power ◽  
Made In

Approach to Stochastic Modeling of Power SystemsThis paper presents an approach to modeling power system that contains sources of stochastic disturbance. It is based on frequency analysis of linearized model of power system. Power system dynamic properties are accounted by equivalent transfer functions of machines and their control equipment. This will allow more accurate calculations for different analysis tasks. Methodology of system linearization is proposed and results of linearized model test are delivered.The research was made in frame of a project with funding participation of the European Commission.

Study on Flow-Induced Vibration Characteristics of Hydraulic Hoist of Large-Span Upwelling Radial Steel Gate

2011 ◽  
Vol 117-119 ◽  
pp. 241-246
Author(s):  
Zhen Hai Gao ◽  
Gen Hua Yan ◽  
Peng Liu ◽  
Fa Zhan Chen ◽  
Fei Ming Lv
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Flow Induced Vibration ◽  
Structural Dynamic ◽  
Large Span ◽  
Response Characteristics ◽  
Lever Action ◽  
Structural Dynamic Characteristics ◽  
Steel Gate

In this paper we conduct study on flow-induced vibration of large-span upwelling radial steel Gate and its hydraulic hoist. Place an emphasis on vibration response characteristics under two working conditions of diversion and drainage, which proves the safety of hydraulic hoist gate vibration caused by gate vibration. Firstly, we study on dynamic characteristics of fluid-structure interaction of association system of gate and start and stop lever, reveals the discipline of the effect fluid having on structural dynamic characteristics. On this basis, flow-induced vibration characteristics under two conditions of with and without start and stop lever action considered. The results indicate that the gate vibration response with hydraulic hoist used decreases, which explains start and stop lever has certain effect of restraining vibration on gate vibration. In addition, under the working condition of drainage the vibration magnitude of start and stop lever is smaller than that of gate body, which explains there is damping action during transference of gate vibration through start and stop lever. The results find out that on the assumption of optimized gate structure and hydraulic arrangement, it is practicable, safe and reliable to adopt hydraulic hoist. The achievement has directive significance on similar projects construction in the future

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