scholarly journals New method for nonlinear seismic analysis in time domain using frequency analysis with superposition of pulse waves

2016 ◽  
Vol 11 (4) ◽  
pp. 377-390
Author(s):  
Hideaki NAGASAKA ◽  
Yoshihito TANAKA ◽  
Ho CHO
Keyword(s):  
Frequency Analysis ◽  
Time Domain ◽  
Seismic Analysis ◽  
New Method ◽  
Pulse Waves

scholarly journals Time Domain Implementation of Transmitting Boundaries in ABAQUS for Discrete Soil-structure Interaction Systems

2020 ◽  
Vol 5 (3) ◽  
pp. 447-462
Author(s):  
J. Rama Raju Patchamatla ◽  
P. K. Emani
Keyword(s):  
Time Domain ◽  
Soil Structure ◽  
Seismic Waves ◽  
Seismic Analysis ◽  
Discrete Models ◽  
Soil Structure Interaction ◽  
Finite Domain ◽  
Infinite Domains ◽  
Structure Interaction ◽  
Transmitting Boundaries

Soil-structure-interaction (SSI) analyses are essential to evaluate the seismic performance of important structures before finalizing their structural design. SSI under seismic condition involves much more complex interaction with soil compared to the dynamic loads having source on the structure. Seismic SSI analysis requires due consideration of site-specific and structure-specific properties to estimate the actual ground motion (scattered motion) experienced at the base of the structure, and subsequently the effects of the scattered motion on the structure. Most challenging aspect of seismic SSI analysis is to implement transmitting boundaries that absorb the artificial reflections of stress waves at the truncated interface of the finite and infinite domains, while allowing the seismic waves to enter the finite domain. In this paper, the time domain implementation of seismic analysis of a soil-structure system is presented using classical discrete models of structure and interactive force boundary conditions for soil. These models represent typical SSI systems- a single Degree of Freedom (DOF) of a spherical cavity with mass attached to its wall, a two DOF system consisting of a mass attached by a nonlinear spring to a semi-infinite rod on elastic foundation, and a three DOF system with additional DOFs for modelling the structural stiffness and damping. The convolution integral representing the force boundary condition on the truncated interface, is evaluated interactively using UAMP user-subroutine in ABAQUS and applied as concentrated forces at the interface (truncated interface) nodes of the bounded domain or generalized-structure domain. The verification problems presented in the paper show the satisfactory performance of the developed MATLAB code and ABAQUS implementation with FORTRAN user-subroutines. The classical phenomena associated with the dynamic soil-structure systems are discussed through the present work.

AN INNOVATIVE TECHNIQUE FOR QUALITY CONTROL OF GEAR PUMPS

2002 ◽  
Vol 09 (04) ◽  
pp. 383-392
Author(s):  
GIULIO FANTI ◽  
ROBERTO BASSO ◽  
MICHELE BERNARDI ◽  
UMBERTO VERZA
Keyword(s):  
Quality Control ◽  
Fourier Transform ◽  
Frequency Analysis ◽  
Time Domain ◽  
Mathematical Tool ◽  
Pressure Data ◽  
Innovative Technique ◽  
Gear Pumps ◽  
The Time Domain ◽  
Discharge Pressure

This paper describes an innovative technique for the quality control of gear pumps based on the frequency analysis of the oscillations of the discharge pressure using a new mathematical tool called "the spectrum of the power cepstrum." It consists in applying Fourier transform of the pressure data sampled in the time domain three times consecutively. The innovative technique makes it possible to obtain an acceptance mask for a set of gear pumps in the same series, in which the class and entity of a defect can be detected.

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