3-D Seismic Code for ILLIAC-IV

Frazier, Gerald A.; Alexander, J. H.; Petersen, Christian M

doi:10.21236/ad0767010

Cited by 4 publications

(8 citation statements)

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“…The notation and the basic concepts of the PM technique needed to explain the representation theorem integration coupling technique developed in the present paper are summarized in Section 2.2. The FE method used in this study is an extensively modified version of the stress waves in solids code (Frazier, Alexander & Petersen 1973). The result is an explicit time domain FE method using a rectangular grid, and the hourglass correction terms which the rectangular grid necessitates (Kosloff & Frazier 1978;Regan 1987).…”

Section: The Rt Integration Methods For Fe To Pm Couplingmentioning

confidence: 99%

Seismic representation theorem coupling: synthetic SH mode sum seismograms for non-homogeneous paths

Regan

Harkrider

1989

Geophysical Journal International

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S U M M A R YIn this paper the methods for representation theorem coupling of finite-element or finite difference calculations and propagator matrix method calculations (Harkrider) are developed. The validity and accuracy of the resulting hybrid method are demonstrated. The resulting hybrid technique can be used to study the propagation of any phase that can be represented in terms of an SH mode sum seismogram, across regional transition zones or other heterogeneities. These heterogeneities may exist in regions which form subsegments of a longer, mostly plane-layered, path. Examples of structures of interest through which such waves can be propagated using these techniques include, regions of crustal thickening or thinning such as continent-ocean transitions or basins,' anomalous bodies of any shape located in the path, and sudden transitions from one layered structure to another. Examples of the types of phases that may be propagated through these structures include Love waves, L,, S, , and S, .

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Section: The Rt Integration Methods For Fe To Pm Couplingmentioning

confidence: 99%

Seismic representation theorem coupling: synthetic SH mode sum seismograms for non-homogeneous paths

Regan

Harkrider

1989

Geophysical Journal International

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“…The nonlinear soil response calculations were performed using the SWIS (Stress Waves in Solids) code (Frazier and Petersen, 1974), modified to accommodate the endochronic constitutive model. SWIS is a finite element code for the transient analysis of one-, two-, and three-dimensional, linear or nonlinear continua.…”

Section: Methodsmentioning

confidence: 99%

“…In fact, for one-dimensional calculations, the method is indistinguishable from that of explicit, Lagrangian finite difference codes. Details of the numerical method are given in Frazier and Petersen (1974), and here we discuss only the use of artificial viscosity, the specification of the incoming motion, and the numerical treatment of the endochronic constitutive model.…”

Section: Nonlinear Calculations Using Swismentioning

confidence: 99%

Simulation of local site response to earthquakes

Day¹,

Read²,

Swanger³

et al. 1980

Open-File Report

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Summary of Final Contract Report ObjectiveThe objective of this investigation is to develop and evaluate a new analytical approach for estimating site-dependent earthquake ground motion for engineering design purposes.The analytical approach is based on assuming physical models for the earthquake source, path wave-propagation effects, and nonlinear soil response at the site, then calculating ground motion using a combination of seismic (layer matrix) and finite element methods. The approach is structured to potentially provide a three-dimensional ground motion capability, although the nonlinear soil response calculations are here limited to one dimension. The predictive capabilities of this approach were examined by comparing ground motion calculations to empirically derived ground motion trends and to ground motion simulations performed using the equivalent linear method. Principal ResultsThe most significant results of this work are the following: (1) A superior soil model, the endochronic model, has been introduced to site evaluation studies.(2) Comparison of the endochronic model with the conventional equivalent linear model has shown the latter to yield excessively conservative ground motion predictions for loose soil deposits in the near field. SummaryFor distances less than about 20 kilometers, there is minimal earthquake ground motion data available, and substantial disagreement exists among empirical relations for predicting design motion characteristics in this distance range. This disagreement reflects the uncertainties associated with extrapolation of the empirical relations to short distances, where data is sparse. To the extent one can construct adequate analytical models for the seismic source, path wave-propagation effects, and site nonlinear response, it becomes possible to simulate ground motion for geologic environments, distance ranges, and earthquake magnitudes for which data is scarce or nonexistent.The SH component of rock-site ground motion at distances 5, 10, and 30 kilometers was synthesized for an earthquake model which consisted of an assemblage of discrete, circular cracks, representing a composite, extended source. It was found that strong motion observations are, in general, inconsistent with a rupture mechanism in which crack growth stops instantaneously. Once more realistic rupture deceleration was incorporated into the model, the SH component of motion alone was apparently adequate for simulating ground motion consistent with observed peak acceleration, peak velocity, and strong motion duration.A new nonlinear constitutive model for soils, the endochronic model, was fit to cyclic shear data for dry sand, and an equivalent linear constitutive model was fit to the same sand data. Using the endochronic model, close agreement was achieved between calculated (solid curves) and observed (dashed curves) stress-strain behavior of dry sand over 300 cycles of deformation, as illustrated below. Crete 2Only-five parameters were required to accomplish the fit to the sand data.The nonlinear e...

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“…8 denotes the local node number for the element, illustrated in Fig. 2 Frazier, et al, 1973. We note that the interpolation functions expressed in natural element coordinates z can be used directly for interpolating field variables within an element, e.g.. x' -local Cartesian coordinates aligned with the curvilinear system at the point x' = 0.…”

Section: 3mentioning

confidence: 99%

“…Further discussion on the treatment of inner element variations in stress is presented in Appendix A. As an incidental note, Frazier, et al, 1973, grids, a one-point integration procedure is equivalent to the cell-centered-stress finite difference method that is commonly used in Lagrangian shock codes.…”

Section: Time Stepping Schemementioning

confidence: 99%