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Analytic features
- It is possible to set parameters in liquefaction by carrying out simulation
for element test.
- It conducts one-dimensional and two-dimensional analyses.
- It is possible to carry out the dynamic analysis of total stress method
and of effective analysis (analysis in liquefaction).
- Applied elements for total stress method (ignoring water pressure) and
applied elements for effective stress method (considering water pressure)
can be used in mixed situations.
- Dynamic analysis of earth and water successively formed on the assumption
of water penetration.
- Plenty of structure models of land (eight categories) are available and
these can be used freely.
- It adopts BFGS, which is a line search for calculating convergence.
- Stable analysis by making automatic adjustment in time steps of dynamic
analysis.
Scope of application
This program is mainly applied to the following investigations.
- Investigation of the dynamic interrelation between land and building structures
by using the total stress method.
- Investigation of stability at an earthquake including earth structures(river
banks, for example).
- Investigation of the lift of structures in the liquid land.
- Investigation of the method against.
- Simulation of experiments such as a centrifugal vibration experiment or
a large-sized vibration table.
- Judgment of minute liquefaction by means of one-dimensional response analysis
during earthquakes.
As available methods against liquefaction are to be investigated, there
are various possible methods: by means of structures, solidarity, sand
compaction, pile and excessive pore water pressure.
Theory of analysis
1.Factor library
- Distortion element on a plain surface
It is possible to define four elements:triangular element at three contact
points,trangular element at six contact points,quadrangular element at
four contact points and quadrangular element at eight contact points.
- Beam element
It is possible to define primary beam element.
- Axial spring element
Definition is given at two contact points.
- Shearing spring element
Definition is given at two contact points.
- Mass element centered on one contact point.
Definition is given at one contact point.
- Damper element
It indicates declining in the axial and shearing directions.
2.Constituent models
- Distortion element model on a plain surface
- Linear elastic model
- Laminated elastic model
- Elastic and complete plastic model
- Modified Ramberg-Osgood model (RO model)
- Modified Hardin-Drnevich model (HD model)
- Ugai-Wakai model (UW-Clay model)
- Pastor-Zienkiewicz model for sand (PZ-Sand model)
- Pastor-Zienkiewicz model for clay (PZ-Clay model)
- Beam element model
Linear elastic model or bilinear model can be used as stability feature
in the axial direction and shearing spring element. It is also possible
to define the concentrated mass at contact points at both the ends of spring.
- Spring element model
As the stability characteristic of the direction of an axis, and the shear
spring element which is not carried out, an alignment elastic model or
a bilinear model is applicable.
Moreover, node concentration mass can be defined with the direction of
an axis and the shear spring element which is not carried out of this product
as the both-ends node of a spring.
3.Mass matrix and damping matrix
- Concentrated matrix and consistent matrix
In this program it is possible to choose either concentrated matrix or
consistent matrix to be applied to mass matrix and damping matrix.
- Mass matrix---Concentrated mass matrix or consistent mass matrix
- Damping matrix---Concentrated damping matrix or consistent damping matrix
However, you have to use consistent damping matrix if you regard Rayleigh
damping as viscous damping.
- Rayleigh damping
Energy damping covers viscous and fugitive dampings as well as aftereffect
damping.In this program Rayleigh damping can be considered to be viscous
damping.
4.Dynamic equation and simultaneous equation
- Degitizing and integral calculus in dynamic equation
- Explicit method---forward calculus of finite differences.
- Implicit method---Newmark-βmethod/HHT-α method/WBZ-α method/Generalized-α
method.
- Solution of simultaneous equation
This program stores into memory total rigid matrix by means of skyline
method.
As solution of simultaneous equation it adopts LDLT resolving method which
is changed from Gaussian elimination.
Representational function of the analyzed results
It supports displaying model diagram, distortion diagram, time history
diagram, drawing of characteristic force of restitution, responsive spectrum
diagram, Fourier spectrum diagram, contour diagram, diagram of cross-section
force, main stress/main distortion. It also supports representation in
animation.
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Introduction
Technical data
