Vibration of a U-shaped steel–concrete composite hollow waffle floor under human-induced excitations

2020 ◽  
Vol 23 (14) ◽  
pp. 2996-3008
Author(s):  
Xi Zhang ◽  
Qing Li ◽  
Yousan Wang ◽  
Qiming Wang
Keyword(s):  
Plate Theory ◽  
Experimental Testing ◽  
Damping Ratio ◽  
Low Frequency ◽  
Threshold Values ◽  
Thin Plate Theory ◽  
Orthotropic Thin Plate ◽  
Floor System ◽  
Vibration Performance ◽  
Position Group

The U-shaped steel–concrete composite hollow waffle floor is an innovative slender large-span floor system, where severe vibration may occur under human-induced excitations. In this research, a theoretical analysis and experimental testing are performed to explore the vibration behaviour of the composite hollow waffle floor. First, the natural frequency formula is proposed based on orthotropic thin plate theory, and the main rigidity calculation for the composite hollow waffle floor is given. Second, the mode shape, frequency and damping ratio of the composite hollow waffle floor are captured by on-site tests and validated by analytical and numerical methods, indicating that the floor has a low-frequency with a low damping ratio. Third, the vibration response of the composite hollow waffle floor is obtained by walking and running tests considering the influence of the frequency, spatial position, group size and route; in addition, the relationships between the values involved in the vibration evaluation are discussed. Finally, the composite hollow waffle floor presents satisfactory vibration performance evaluated by the threshold values among the current codes.

scholarly journals Experimental and Analytical Study on the Vibration Performance of U-Shaped Steel-Concrete Composite Hollow Waffle Slab

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Xi Zhang ◽  
Qiming Wang ◽  
Yousan Wang ◽  
Qing Li
Keyword(s):  
Damping Ratio ◽  
Low Frequency ◽  
Field Testing ◽  
Mode Shapes ◽  
Large Span ◽  
Human Perceptions ◽  
Vibration Responses ◽  
Activity Types ◽  
Floor System ◽  
Vibration Performance

The large-span floor system being lightweight with low frequency and low damping is prone to suffer severe vibration under human excitations. In this research, the vibration performance of an innovative large-span U-shaped steel-concrete composite hollow waffle (CHW) slab was studied based on field testing and theoretical analysis. First, the modal properties of CHW slab including mode shapes, frequencies, and damping ratio were captured by on-site tests and validated by the finite element method, indicating the CHW slab is a low-frequency floor system with a low damping ratio. Second, the vibration responses of CHW slab under heel-drop and jumping excitations were studied considering the impacts of spatial position, tester number, and activity types. Third, the CHW slab shows excellent vibration serviceability proved by the frequency, accelerations, and human perceptions threshold with the current codes. Meanwhile, the paper gives appropriate threshold values for the CHW slab under impulsive excitation. Finally, the natural frequency formula for the CHW slab derived by the Rayleigh–Ritz energy method agrees well with the measurements.

Application of Orthotropic Thin Plate Theory to Filled Steel Grid Decks for Bridges

2007 ◽  
Vol 12 (6) ◽  
pp. 807-810 ◽  
Author(s):  
Haoxiong Huang ◽  
Victor N. Kaliakin ◽  
Michael J. Chajes ◽  
Dennis R. Mertz ◽  
Harry W. Shenton
Keyword(s):  
Thin Plate ◽  
Plate Theory ◽  
Thin Plate Theory ◽  
Orthotropic Thin Plate

scholarly journals Semi-analytical static analysis of nonlocal strain gradient laminated composite nanoplates in hygrothermal environment

2021 ◽  
Vol 43 (5) ◽  
Author(s):  
Giovanni Tocci Monaco ◽  
Nicholas Fantuzzi ◽  
Francesco Fabbrocino ◽  
Raimondo Luciano
Keyword(s):  
Thin Plate ◽  
Strain Gradient ◽  
Plate Theory ◽  
Laminated Composite ◽  
Equilibrium Equations ◽  
Thin Plate Theory ◽  
Bending Behavior ◽  
Hygrothermal Environment ◽  
Load Types ◽  
Novel Applications

AbstractIn this work, the bending behavior of nanoplates subjected to both sinusoidal and uniform loads in hygrothermal environment is investigated. The present plate theory is based on the classical laminated thin plate theory with strain gradient effect to take into account the nonlocality present in the nanostructures. The equilibrium equations have been carried out by using the principle of virtual works and a system of partial differential equations of the sixth order has been carried out, in contrast to the classical thin plate theory system of the fourth order. The solution has been obtained using a trigonometric expansion (e.g., Navier method) which is applicable to simply supported boundary conditions and limited lamination schemes. The solution is exact for sinusoidal loads; nevertheless, convergence has to be proved for other load types such as the uniform one. Both the effect of the hygrothermal loads and lamination schemes (cross-ply and angle-ply nanoplates) on the bending behavior of thin nanoplates are studied. Results are reported in dimensionless form and validity of the present methodology has been proven, when possible, by comparing the results to the ones from the literature (available only for cross-ply laminates). Novel applications are shown both for cross- and angle-ply laminated which can be considered for further developments in the same topic.

Study on Gradual Deformation and Prediction Model of the Mined Overburden

2012 ◽  
Vol 524-527 ◽  
pp. 699-704
Author(s):  
Xiao Gang Xia ◽  
Yun Feng Yang
Keyword(s):  
Boundary Condition ◽  
Plate Theory ◽  
Surface Expression ◽  
Rock Deformation ◽  
Double Trigonometric Series ◽  
Mechanics Model ◽  
Thin Plate Theory ◽  
Gradual Deformation ◽  
Exchange Condition ◽  
Gradual Transformation

Based on the overburden three caving feature, the deformation of mining rock process was devided and the criterion of gradual transformation of each stages deformation were given. Then , combined the thin-plate theory, the differential models were derived for rock deformation in level and similar to level bured condition. The boundary condition of each models and exchange condition between different models were put forward and the gradual mechanics model was set up.The subsidence model before roof collapse was solved by Navier double trigonometric series and the deflection surface expression of rock deformation was put forword. At last, the reliability and practicality of the models was verified by engineering examples.

scholarly journals Detection of infrasound by the Atlantic cod

1986 ◽  
Vol 125 (1) ◽  
pp. 197-204 ◽  
Author(s):  
O. Sand ◽  
H. E. Karlsen
Keyword(s):  
Ambient Noise ◽  
Atlantic Cod ◽  
Low Frequency ◽  
Directional Pattern ◽  
Frequency Noise ◽  
Threshold Values ◽  
Sensory Inputs ◽  
A Value ◽  
Cardiac Conditioning ◽  
Lower Frequencies

Below about 50 kHz the level of ambient noise in the sea increases continuously towards lower frequencies. In the infrasound range the spectral slope is particularly steep. This low-frequency noise may propagate long distances with little attenuation, causing a directional pattern of infrasound in the sea. Using a standing-wave acoustic tube, we have studied the sensitivity of cod to infrasound down to 0.1 Hz by means of the cardiac conditioning technique. The threshold values, measured as particle acceleration, showed a steady decline towards lower frequencies below 10 Hz, reaching a value close to 10(−5)ms-2 at 0.1 Hz. The spectrum level at 0.1 Hz in the sea ranges between 120 and 180 dB (re 1 microPa), with corresponding particle accelerations from less than 10(−6) to more than 10(−4)ms-2. The sensitivity of cod is thus sufficient to detect the highest levels of ambient infrasound, and we put forward the hypothesis that fish may utilize information about the infrasound pattern in the sea for orientation during migration, probably in addition to an array of other sensory inputs.

scholarly journals A Comparison on Numerical Simulation Models for Vibrational Performances of the Wood Truss Joist Floor System

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yinlan Shen ◽  
Haibin Zhou ◽  
Shuo Xue ◽  
Jinchuan Zhang
Keyword(s):  
Simulation Models ◽  
Metal Plate ◽  
Modeling Methods ◽  
Time Period ◽  
Long Time ◽  
Flexible Metal ◽  
Plate Connections ◽  
Simplified Modeling ◽  
Floor System ◽  
Vibration Performance

Wood truss joist floors are increasingly used to replace traditional solid timber joist floors in low-rise timber houses. An understanding of the vibration performance of wood truss joist floors is critical for the design and serviceability of the floors. It is difficult to model wood truss joist floors accurately because of the complicated boundary conditions and numerous sophisticated flexible connections. This paper discusses three simplified modeling methods for the wood truss joist floor system. The modeling results were validated by a series of static deflection tests and vibration modes and frequencies tests of a full-size floor. And predictive analysis of human-induced vibration of the floor was also conducted. The vibration characteristics of the wood truss joist floor were investigated. The examination of the applicability of these modeling methods was provided. The results indicate that the point loading deflection more easily affects the deflection of the adjacent joist. However, the deflection influence on other joists that are three spaces away is minimal. Walking on the wood truss joist floor produces steep vibration acceleration fluctuations at the floor center for a relatively long time period. The sheathing-to-joist connections and the metal plate connections of the joists have significant influences on the vibration response of the wood truss joist floor. The modeling method, which considers the flexible metal plate connections and flexible sheathing-to-joist connections, performs best for predicting the vibration performance of the floor.

Normal Loading on a Wedge-Shaped Plate

1955 ◽  
Vol 6 (3) ◽  
pp. 196-204 ◽  
Author(s):  
D. E. R. Godfrey
Keyword(s):  
Thin Plate ◽  
Mellin Transform ◽  
Plate Theory ◽  
Normal Loading ◽  
Thin Plate Theory

SummaryThe equations of thin plate theory are expressed in polar co-ordinates and transformed using the Mellin transform. Problems involving discontinuous and isolated normal loadings may then be solved in the case of the built-in or freely supported wedge-shaped boundary.

Analysis of Low Frequency Oscillation in Interconnected Power System under Hedge Operation Mode

2014 ◽  
Vol 536-537 ◽  
pp. 1542-1546
Author(s):  
Xun Gao ◽  
Jie Meng ◽  
Yi Qun Li ◽  
Ying Wang ◽  
Wen Chao Zhang
Keyword(s):  
Power System ◽  
Power Flow ◽  
Power Grid ◽  
Damping Ratio ◽  
Operation Mode ◽  
Oscillation Mode ◽  
Low Frequency ◽  
Operating Mode ◽  
Low Frequency Oscillation ◽  
Interconnected Power System

A phenomenon that the damping ratio will decrease when the power flows from both sides to the primary power grid is summarized and analyzed in the paper. Based on analysis of the damping ratio change of West Inner Mongolia-Shandong oscillation under the sequential operation mode and the hedge operation mode, a three-machine equivalent system is established to study edge to edge (ETE) oscillation mode under hedge operating mode of the power system. The influence of magnitudes and trends of power flow on damping ratio is analyzed, and the reason that why damping ratios decreases when both sides send power to the mid-side power grid is explained.

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