YUSAYUSA was originally developed by Ishihara and Towhata¹⁾ for the seismic response analysis of level ground based on effective stress. It is one of the most frequently used computer program for liquefaction analysis. Hyperbolic model was used in the original version. I improved so that Ramberg-Osgood model can also be used and stress-paths²⁾. Because of this improvement, a new name YUSAYUSA-2 is used, but it is usually called just YUSAYUSA. Of course, original functions are also available.

Related programs are as follows;

Computer program POSTEQ can be useful tool to draw maximum responses.

1)Ishihara, K. and Towhata, I. (1980): One-dimensional Soil Response Analysis during Earthquake Based on Effective Stress Method, Journal of the Faculty of Engineering, Vol. XXXV, No. 4, The University of Tokyo, pp. 656-700；Ishihara, K. and Towhata, I. (1982): Dynamic response analysis of level ground based on the effective stress method, Soil Mechanics - Transient and Cyclic Loads, Pande, G. N. and Zienkiewicz, O. C. ed., John Wiley & Sons, pp. 133-172
(Above two paper is exactly identical. The first paper seems difficult to obtain. The second one is a part of the book.

2)Yoshida, N., Kiku, H. and Towhata, I. (1999): An improvement of effective stress dynamic response analysis code YUSAYUSA, Proc., The 34h Japan National Conference on Geotechnical Engineering, pp. 2105-2106 (in Japanese)

SHAKE¹⁾ is very famous as one-dimensional seismic response analysis based on equivalent linear method. However, SHAKE has two significant shortage²⁾. DYNEQ solved these shortages³⁾. It has variety of functions, such as to prepare many empirical equations for strain dependent shear modulus and damping ratio, to use variety of complex moduli, scattering attenuation, etc. Of course it has the function same as original SHAKE and SHAKE91.

Related programs are as follows;

PROPCK.exe: Digital output of stress-strain relationships used in the DYNEQ, which is useful to draw material data. POSTEQ is very convenient tool to draw maximum response figure.

VECTOR can be used to convert time history output to one array vector image to use, for example by Excel

　DYNES3D is a computer program retrieved from multi-purpose two-dimensional FEM program STADAS for one-dimensional truly nonlinear seismic response analysis. It prepares constitutive models that can perfectly simulate strain dependent shear modulus and damping ratio係¹⁾²⁾. It also prepares many constitutive models. One of the big merit of DYNES3D is that it can handle two horizontal and vertical directional earthquake input.

Related programs are as follows;

Computer program POSTEQ can be useful tool to draw maximum responses. VECTOR can be used to convert time history output to one array vector image to use, for example by Excel

1)Ishihara, K., Yoshida, N. and Tsujino, S. (1985): Modelling of stress-strain relations of soils in cyclic loading, Proc. 5th International Conference for Numerical Method in Geomechanics, Nagoya, Vol. 1, pp. 373-380, 1985

2Yoshida, N., Tsujino, S. and Ishihara, K. (1990): Stress-strain model for nonlinear analysis of horizontally layered deposit, Summaries of the Technical Papers of Annual Meeting of AIJ, Chugoku, Vol. B (Structure I), pp. 1639-1640 (in Japanese)

STADAS is a multi-purpose two dimensional FE computer program. At present, it is not released because it is difficult to use. It is releases to the engineer whom I understand he has sufficient skill.

　DYNEQ2D is a two-dimensional extension of DYNEQ. Wait a little to release it.

POST2D is developed in order to draw result of FE analysis for technical papers and report. It does not have function to make movie, but variety of figures for tensor, vector and scalar. Output file is same with Illustrator (version 3.0); therefore, the result is useful because many drawing software can read it.

It can draw structural figure and vector (displacement, acceleration, etc.), tensor (stress, strain etc.) and scalar (excess PWP, contour, etc.

Result of the computer program I release can be easily read. Variety of other computer program can also be read by specifying Format.

DYNEQ is a postprocessor for one-dimensional seismic response analysis of ground. It has various functions to draw such as soil profiles, maximum responses. Output file is, same with POST2D, same with Illustrator version 3.

EQWAVE treats earthquake waves. Integration, differentiation, Fourier analysis, response spectrum (including tripatites figure), variety of earthquake motion indices, etc. can be calculated by EQWAVE.

Generally speaking, digital data of time history are written in the file with, for example, 8 data in line. However, if one want to draw time history by using, for example, Excel, one need to convert the data sequentially. VECTOR and VECTRIZE are very simple program to convert. VECTOR is for the computer program I release and VECTORIZ is for arbitrary data. There is no manual because it is an interactive way, so you just type VECTOR or VECTRIZE (English version VECTORIZE-E, of courser one can change name after download) and respond from programs.