A Simplified Model of SSI Dynamic Analysis

2012 ◽  
Vol 446-449 ◽  
pp. 334-339
Author(s):  
Zhi Ying Zhang ◽  
Ying Li ◽  
Qing Sun
Keyword(s):  
Dynamic Analysis ◽  
Soil Structure ◽  
Design Method ◽  
Simplified Model ◽  
Lumped Mass ◽  
Foundation Soil ◽  
Linear Elastic ◽  
Lumped Mass Method ◽  
Actual Mechanism ◽  
Seismic Design Method

Aiming at the problem of dynamic analysis of SSI system, the dynamic influence of different parts of foundation soil is studied on the linear elastic assumption according to the actual mechanism of Soil-Structure Interaction (SSI); in addition, a simplified model on the condition of the lumped mass method is put forward and the corresponding motion equations of SSI system are built, which can be a reference for the structural seismic design method considering SSI effect.

Seismic Response Analysis on Pile-Soil Couple System by Lumped Mass Method

2011 ◽  
Vol 94-96 ◽  
pp. 1420-1423
Author(s):  
Li Qiang Wang ◽  
Yuan Zhan Wang
Keyword(s):  
Differential Equation ◽  
Seismic Response ◽  
Soil Structure ◽  
Couple System ◽  
Response Analysis ◽  
Lumped Mass ◽  
Deep Foundation ◽  
Lumped Mass Method ◽  
Model Pile ◽  
Mechanical Characters

Pile is widely used as deep foundation in civil engineering. The dynamic interaction between pile and soil is an important problem in the field of soil-structure interaction. This paper established a model to calculate the seismic response of pile-soil couple system. In this model, pile and soil are regarded as lumped mass, soil was divided into two parts: the far region soil and near pile region soil. These two parts are simulated by different mechanical characters. A differential equation of motion of pile-soil couple system was established in the paper, this differential equation can be solved by Wilson-θ method. An example was introduced to study the behavior of pile-soil couple system.

Dynamic analysis of finger seal using equivalent model based on distributed mass method

2014 ◽  
Vol 228 (16) ◽  
pp. 2992-3005 ◽  
Author(s):  
Guo-Ding Chen ◽  
Fei Lu ◽  
Qiang-Peng Yu ◽  
Hua Su
Keyword(s):  
Dynamic Analysis ◽  
Equivalent Model ◽  
Leakage Flow ◽  
Lumped Mass ◽  
Model Based ◽  
Lumped Mass Method ◽  
Leakage Flow Rate ◽  
Dynamic Performances ◽  
Contact Pressures ◽  
Good Agreement

Dynamic analysis of finger seal can be performed by finite element method or equivalent model based on lumped mass method now available, which is difficult in meeting both the acceptable calculation time and accuracy simultaneously. For this reason, interactions between finger elements are considered and the equivalent dynamic model based on distributed mass method is proposed in this article. Seal dynamic performances are obtained by using this model to calculate the equivalent parameters, air leakage flow, and the contact behavior between finger seal and the rotor. The work to be presented here concerns the mapping of dynamic behavior of the finger seal with a stack of three finger elements, including the dynamic displacement responses of finger elements, the leakage clearances, and the contact pressures between the finger elements and the rotor, as well as the leakage flow rate and the wear rate. The results calculated by the equivalent model presented in this study are evaluated by comparison with the published experimental data and results from the model based on lumped mass method, which shows that the equivalent model based on distributed mass method is far superior to that based on lumped mass method because the calculations are in good agreement with the experimental results.

3-D LUMPED MASS METHOD OF DYNAMIC ANALYSIS FOR HIGH-RISE BUILDING

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Zorigt Tumurbaatar ◽  
Haruyuki Yamamoto
Keyword(s):  
Dynamic Analysis ◽  
Stiffness Matrix ◽  
Structural Response ◽  
Building Structures ◽  
Lumped Mass ◽  
Total Size ◽  
Building Model ◽  
High Rise ◽  
High Rise Building ◽  
Lumped Mass Method

This study is related to decreasing size of stiffness matrix of high-rise building by using floor diaphragm constraints. The combined actions of horizontal structural members such as slab and beams produce structural response that is much stiffer than vertical elements such as columns. In structural analysis of high-rise building model, absolute rigid slab and vertical structure are working together for lumped mass method. Each lumped mass node has 6 degree of freedoms which is very suitable for high-rise building calculation. The lumped mass is consisted of slab and beams, on the other hand the system’s stiffness matrix is only assembly of columns and braces. High-rise building lumped mass model’s stiffness matrix size is n=6 x m (n; total size of stiffness matrix, m; total floor number). In the step by step calculation, total unknown number is decrease enough which means we can easily calculate high-rise building structures for dynamic analysis also nonlinear step by step calculation using simple personal computer. If building model has large span and short height, in this case rigid slab theory will not satisfied. This idea is more suitable for high-rise building calculation.

Seismic Design Method for Hybrid Viaduct in Japanese Railways

2000 ◽  
Vol 16 (20) ◽  
pp. 338-346
Author(s):  
Kiyomitsu MURATA ◽  
Masato YAMADA ◽  
Tomohiro TAKAYAMA ◽  
Masanori KINOSHITA
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Seismic Design Method

Dynamic analysis of a helical gear reduction by experimental and numerical methods

2020 ◽  
Vol 68 (1) ◽  
pp. 48-58
Author(s):  
Chao Liu ◽  
Zongde Fang ◽  
Fang Guo ◽  
Long Xiang ◽  
Yabin Guan ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Fourth Order ◽  
Numerical Models ◽  
Helical Gear ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Lumped Mass ◽  
Gear Mesh

Presented in this study is investigation of dynamic behavior of a helical gear reduction by experimental and numerical methods. A closed-loop test rig is designed to measure vibrations of the example system, and the basic principle as well as relevant signal processing method is introduced. A hybrid user-defined element model is established to predict relative vibration acceleration at the gear mesh in a direction normal to contact surfaces. The other two numerical models are also constructed by lumped mass method and contact FEM to compare with the previous model in terms of dynamic responses of the system. First, the experiment data demonstrate that the loaded transmission error calculated by LTCA method is generally acceptable and that the assumption ignoring the tooth backlash is valid under the conditions of large loads. Second, under the common operating conditions, the system vibrations obtained by the experimental and numerical methods primarily occur at the first fourth-order meshing frequencies and that the maximum vibration amplitude, for each method, appears on the fourth-order meshing frequency. Moreover, root-mean-square (RMS) value of the acceleration increases with the increasing loads. Finally, according to the comparison of the simulation results, the variation tendencies of the RMS value along with input rotational speed agree well and that the frequencies where the resonances occur keep coincident generally. With summaries of merit and demerit, application of each numerical method is suggested for dynamic analysis of cylindrical gear system, which aids designers for desirable dynamic behavior of the system and better solutions to engineering problems.

scholarly journals Time and Frequency Domain Dynamic Analysis of Offshore Mooring

2021 ◽  
Vol 9 (7) ◽  
pp. 781
Author(s):  
Shi He ◽  
Aijun Wang
Keyword(s):  
Dynamic Analysis ◽  
Frequency Domain ◽  
Time Domain ◽  
Linearization Method ◽  
Euler Method ◽  
Single Component ◽  
Hydrodynamic Drag ◽  
Lumped Mass ◽  
Mooring Lines ◽  
The Time Domain

The numerical procedures for dynamic analysis of mooring lines in the time domain and frequency domain were developed in this work. The lumped mass method was used to model the mooring lines. In the time domain dynamic analysis, the modified Euler method was used to solve the motion equation of mooring lines. The dynamic analyses of mooring lines under horizontal, vertical, and combined harmonic excitations were carried out. The cases of single-component and multicomponent mooring lines under these excitations were studied, respectively. The case considering the seabed contact was also included. The program was validated by comparing with the results from commercial software, Orcaflex. For the frequency domain dynamic analysis, an improved frame invariant stochastic linearization method was applied to the nonlinear hydrodynamic drag term. The cases of single-component and multicomponent mooring lines were studied. The comparison of results shows that frequency domain results agree well with nonlinear time domain results.

Research Situation on the Performance-Based Seismic Design Method for Reinforced Concrete Structure

2010 ◽  
Vol 163-167 ◽  
pp. 1757-1761
Author(s):  
Yong Le Qi ◽  
Xiao Lei Han ◽  
Xue Ping Peng ◽  
Yu Zhou ◽  
Sheng Yi Lin
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Design Method ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Seismic Evaluation ◽  
Seismic Codes ◽  
Performance Based Seismic Design ◽  
Capacity Calculation ◽  
Seismic Design Method

Various analytical approaches to performance-based seismic design are in development. Based on the current Chinese seismic codes，elastic capacity calculation under frequent earthquake and ductile details of seismic design shall be performed for whether seismic design of new buildings or seismic evaluation of existing buildings to satisfy the seismic fortification criterion “no damage under frequent earthquake, repairable under fortification earthquake, no collapse under severe earthquake”. However, for some special buildings which dissatisfy with the requirements of current building codes, elastic capacity calculation under frequent earthquake is obviously not enough. In this paper, the advanced performance-based seismic theory is introduced to solve the problems of seismic evaluation and strengthening for existing reinforced concrete structures, in which story drift ratio and deformation of components are used as performance targets. By combining the features of Chinese seismic codes, a set of performance-based seismic design method is established for reinforced concrete structures. Different calculation methods relevant to different seismic fortification criterions are adopted in the proposed method, which solve the problems of seismic evaluation for reinforced concrete structures.

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