scholarly journals Study on Pounding Response of Adjacent Inelastic SDOF Structures Based on Dimensional Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xuyong Chen ◽  
Huipeng Guo ◽  
Tao Wang ◽  
Qiaoyun Wu
Keyword(s):  
Dimensional Analysis ◽  
Frequency Ratio ◽  
Structural Parameters ◽  
Contact Process ◽  
Structural Response ◽  
Mass Ratio ◽  
Earthquake Excitation ◽  
Kelvin Model ◽  
Dimensionless Equation ◽  
Adjacent Structures

The dimensional analysis method is applied to study the pounding response of two inelastic single-degree-of-freedom (SDOF) structures under simplified earthquake excitation. The improved Kelvin pounding model is used to simulate the force and deformation of the collider during the contact process. Using bilinear interstory resistance model to simulate the inelastic characteristics of SDOF structures, the expression of dimensionless pounding force and the dimensionless equation of motion during the pounding process are deduced. When dimensionless parameters are used to represent the colliding equation of adjacent inelastic SDOF structures, the variables affecting the pounding response of the adjacent structures are reduced from 14 to 11, which can clearly reflect the rules during the pounding process. The correctness and superiority of the improved Kelvin model are verified by comparing the pounding responses between the improved Kelvin model and Kelvin model. The pounding response of the two inelastic SDOF structures with improved Kelvin model is illustrated in the form of spectra, and the self-similarity of pounding response of the two inelastic SDOF structures is revealed. The effects of structural parameters on the pounding response are analyzed. The results show that the effects of mass ratio, frequency ratio, and initial spacing between the adjacent inelastic SDOF structures on the pounding response of the left-side structure (with smaller mass and stiffness) are closely related to the division of spectral regions. For the right-side structure with larger mass and stiffness, the amplification of pounding on structural response increases with the increase of mass ratio Π m and decreases with the increase of frequency ratio μ and structural spacing Π d .

scholarly journals Theoretical and Experimental Study of the Pounding Response for Adjacent Inelastic MDOF Structures Based on Dimensional Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Qiaoyun Wu ◽  
Ziliang Liu ◽  
Tao Wang ◽  
Xuyong Chen
Keyword(s):  
Dimensional Analysis ◽  
Impact Force ◽  
Theoretical Method ◽  
Shaking Table ◽  
Earthquake Excitation ◽  
Kelvin Model ◽  
Matlab Program ◽  
Steel Frame Structures ◽  
Collision Processes ◽  
The Impact

Dimensional analysis is applied to study the pounding response of two inelastic multidegree of freedom (MDOF) structures under simplified earthquake excitation. The forces and deformations of the collision processes are simulated by adopting the improved Kelvin pounding model. The inelastic characteristics of MDOF structures are described by the bilinear interstory resistance model, and the representations of dimensionless impact force and the dimensionless motion equation in the pounding process are derived. On the basis of the above-mentioned theoretical deduction, the superiority of the improved Kelvin model is verified by comparing the impact response of the improved Kelvin model and the Kelvin model. Finally, the validity of the proposed theoretical method is further proved by the comparison between results from the shaking table tests of adjacent four-story and three-story steel frame structures and the corresponding numerical results obtained by the MATLAB program.

The Numerical Simulation of Two-Degrees-of-Freedom Vortex-Induced Vibrations of Circular Cylinder with High Mass-Ratio

2013 ◽  
Vol 284-287 ◽  
pp. 557-561
Author(s):  
Jie Li Fan ◽  
Wei Ping Huang
Keyword(s):  
Circular Cylinder ◽  
Drag Force ◽  
Frequency Ratio ◽  
Lift Force ◽  
Degrees Of Freedom ◽  
Cross Flow ◽  
High Mass ◽  
Mass Ratio ◽  
Main Frequency ◽  
Line Amplitude

The two-degrees-of-freedom VIV of the circular cylinder with high mass-ratio is numerically simulated with the software ANSYS/CFX. The VIV characteristic is analyzed in the different conditions (Ur=3, 5, 6, 8, 10). When Ur is 5, 6, 8 and 10, the conclusion which is different from the cylinder with low mass-ratio can be obtained. When Ur is 3, the frequency of in-line VIV is twice of that of cross-flow VIV which is equal to the frequency ratio between drag force and lift force, and the in-line amplitude is much smaller than the cross-flow amplitude. The motion trace is the crescent. When Ur is 5 and 6, the frequency ratio between the drag force and lift force is still 2, but the main frequency of in-line VIV is mainly the same as that of cross-flow VIV and the secondary frequency of in-line VIV is equal to the frequency of the drag force. The in-line amplitude is still very small compared with the cross-flow amplitude. When Ur is up to 8 and 10, the frequency of in-line VIV is the same as the main frequency of cross-flow VIV which is close to the inherent frequency of the cylinder and is different from the frequency of drag force or lift force. But the secondary frequency of cross-flow VIV is equal to the frequency of the lift force. The amplitude ratio of the VIV between in-line and cross-flow direction is about 0.5. When Ur is 5, 6, 8 and 10, the motion trace is mainly the oval.

scholarly journals Structural Reliability Sensitivities under Nonstationary Random Vibrations

2013 ◽  
Vol 2013 ◽  
pp. 1-21 ◽  
Author(s):  
Rita Greco ◽  
Francesco Trentadue
Keyword(s):  
Structural Reliability ◽  
Structural Parameters ◽  
Time Integration ◽  
Structural Response ◽  
Integration Scheme ◽  
Structural Systems ◽  
Frame Building ◽  
Time Integration Scheme ◽  
Noise Input ◽  
The Time Domain

Response sensitivity evaluation is an important element in reliability evaluation and design optimization of structural systems. It has been widely studied under static and dynamic forcing conditions with deterministic input data. In this paper, structural response and reliability sensitivities are determined by means of the time domain covariance analysis in both classically and nonclassically damped linear structural systems. A time integration scheme is proposed for covariance sensitivity. A modulated, filtered, white noise input process is adopted to model the stochastic nonstationary loads. The method allows for the evaluation of sensitivity statistics of different quantities of dynamic response with respect to structural parameters. Finally, numerical examples are presented regarding a multistorey shear frame building.

A Probabilistic High-Pressure Zone Model of Dynamic Ice Structure Interactions and Associated Ice-Induced Vibrations

2021 ◽  
Author(s):  
Ridwan Hossain ◽  
Rocky Taylor ◽  
Lorenzo Moro
Keyword(s):  
High Pressure ◽  
Theoretical Calculations ◽  
Structural Parameters ◽  
Structural Response ◽  
Zone Model ◽  
Modelling Framework ◽  
Lower Amplitude ◽  
Average Strain Rate ◽  
High Pressure Zone ◽  
Lock In

Abstract During ice-structure interactions that are dominated by ice compressive failure, the majority of the ice loads are transmitted through localized contact regions known as high-pressure zones (hpzs). This paper presents a probabilistic modelling framework for dynamic ice-structure interaction based on the mechanics of hpzs. Individual hpzs are modelled as a nonlinear spring-damper system where the stiffness is modelled as a function of nominal strain, with the degree of softening depending on the average strain-rate. Both spalling and crushing failure mechanisms were assessed in the context of periodical sinusoidal response. For spall dominated failure, the model structure showed presence of frequency lock-in in the speed range of 100–125mm/s, beyond which the failure was found to be random in nature with lower amplitude of structural response. The amplitude was also found to be significantly influenced by structural parameters with structural damping having the highest contribution. For pure crushing, an estimated equilibrium layer thickness based on theoretical calculations also showed presence of frequency lock-in. The work highlights the importance of understanding the interplay between these mechanisms, as well as the role of ice conditions and structural parameters on the processes that dominate an interaction.

Additive manufacturing and mechanical properties of lattice-curved structures

2019 ◽  
Vol 25 (5) ◽  
pp. 895-903 ◽  
Author(s):  
Enrique Cuan-Urquizo ◽  
Mario Martínez-Magallanes ◽  
Saúl E. Crespo-Sánchez ◽  
Alfonso Gómez-Espinosa ◽  
Oscar Olvera-Silva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Structural Parameters ◽  
Structural Response ◽  
Layered Structures ◽  
Lattice Structures ◽  
Structure Property ◽  
Content Type ◽  
Fused Deposition ◽  
Curved Structures

Purpose The purpose of this paper is to study the feasibility of the fabrication of circle arc curved-layered structures via conventional fused deposition modeling (FDM) with three-axis machines and to identify the main structural parameters that have an influence on their mechanical properties. Design/methodology/approach Customized G-codes were generated via a script developed in MATLAB. The G-codes contain nozzle trajectories with displacements in the three axes simultaneously. Using these, the samples were fabricated with different porosities, and their influence on the mechanical responses evaluated via tensile testing. The load-displacement curves were analyzed to understand the structure-property relationship. Findings Circled arc curved-layered structures were successfully fabricated with conventional three-axis FDM machines. The response of these curved lattice structures under tensile loads was mapped to three main stages and deformation mechanisms, namely, straightening, stretching and fracture. The micro-structure formed by the transverse filaments affect the first stage significantly and the other two minimally. The main parameters that affect the structural response were found to be the transverse filaments, as these could behave as hinges, allowing the slide/rotation of adjacent layers and making the structure more shear sensitive. Research limitations/implications This paper was restricted to arc-curved samples fabricated with conventional three-axis FDM machines. Originality/value The FDM fabrication of curved-structures with controlled porosity and their relation to the resulting mechanical properties is presented here for the first time. The study of curved-lattice structures is of great relevance in various areas, such as biomedical, architecture and aerospace.

FORMULATION OF MATHEMATICAL MODEL FOR MAINTENANCE COST OF A STONE CRUSHING PLANT BASED ON DIMENSIONAL ANALYSIS AND MULTIPLE REGRESSION

2013 ◽  
pp. 1-6
Author(s):  
PROF. ANJALI J. JOSHI ◽  
DR. JAYANT P. MODAK
Keyword(s):  
Mathematical Model ◽  
Multiple Regression ◽  
Dimensional Analysis ◽  
Least Square Method ◽  
Least Square ◽  
Maintenance Cost ◽  
Design Data ◽  
Static And Dynamic Analysis ◽  
Dimensionless Equation ◽  
Crushing Plant

This paper presents the approach for the mathematical modeling of maintenance cost for the set up of new Stone Crushing Plant based on the dimensional analysis and multiple regression. Presented maintenance cost mathematical model is derived based on the generated design data. Design data is generated from actual design of all stone crushing plants followed by static and dynamic analysis. Estimation of design data is carried out based on the assumed plant layout. Dimensional analysis is used to make the independent and dependent variables dimensionless and to get dimensionless equation. Later, multiple regression analysis is applied to this dimensionless equation to obtain the index values based on the least square method. The mathematical model of maintenance cost is formulated using these obtained index values. Finally, the formulated model is evaluated on the basis of correlation and root mean square error between the computed values by model and the estimated values.

scholarly journals The Shock Characteristics of Tilted Support Spring Packaging System with Critical Components

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
An-Jun Chen
Keyword(s):  
Frequency Ratio ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Frequency Parameter ◽  
Mass Ratio ◽  
Packaging System ◽  
Parameter Ratio ◽  
Shock Response ◽  
Shock Response Spectrum ◽  
Critical Components

The nonlinear dynamical equations of tilted support spring packaging system with critical components were obtained under the action of half-sine pulse. To evaluate the shock characteristics of the critical components, a new concept of three-dimensional shock response spectrum was proposed. The ratio of the maximum shock response acceleration of the critical components to the peak pulse acceleration, the dimensionless pulse duration, and the frequency parameter ratio of system or the angle of tilted support spring system were three basic parameters of the three-dimensional shock response spectrum. Based on the numerical results, the effects of the peak pulse acceleration, the angle of the tilted support spring, the frequency parameter ratio, and the mass ratio on the shock response spectrum were discussed. It is shown that the effects of the angle of the tilted support spring and the frequency ratio on the shock response spectrum are particularly noticeable, increasing frequency parameter ratio of the system can obviously decrease the maximum shock response acceleration of the critical components, and the peak of the shock response of the critical components can be decreased at low frequency ratio by increasing mass ratio.

Precision and Dimensional Analysis about Parallel Mechanism Having Less Degree of Freedom Based on Differential Geometry

2014 ◽  
Vol 940 ◽  
pp. 509-512 ◽  
Author(s):  
De Xing Zheng ◽  
Bin Wang
Keyword(s):  
Differential Geometry ◽  
Dimensional Analysis ◽  
Parallel Mechanism ◽  
Structural Parameters ◽  
Maximum Error ◽  
Error Model ◽  
Degree Of Freedom ◽  
Vector Model ◽  
Parallel Mechanisms ◽  
Output Error

A 3-PUU parallel mechanism was studied, which can perform one-dimensional translation about z-axis and two-dimensional rotations about y-axis and x-axis. This paper shows the study about the precision analysis, the dimensional analysis and the synthesis problem of the parallel mechanism having less degree of freedom. First, the closed-loop vector model was built based on analyzing the branched-chains of 3-PUU, the pose error model was built through the differential geometry, and the error model of positive solutions was obtained which contains all the structural parameters errors. For the error of structural parameters given, the pose output error can be solved out by application of this model, the area of maximum error is found out. And the influence of pose output error was analyzed with postures changed. The dimensional analysis of 3-PUU was also done by this error model, and the reasonable selection of mechanism parameters was discussed. And then the rationality of structure dimensional design was discussed in this paper. Finally, this method also may be used in the dimensional analysis of other less freedom parallel mechanisms.

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