Simple Structural Analysis Research Articles

Modeling Laterally Loaded Light‐Frame Buildings

Current capabilities of accurately predicting the behavior of the various subassemblies of light‐frame wood structures (walls, floors, and roofs) now meet (or exceed) the ability to characterize material properties. However, subassembly analysis techniques are not commonly incorporated in design practice. The deficiency lies in the inability to efficiently predict the interaction of the subassemblies which yields the behavior of the entire structure. The purpose of this study is to develop and validate a simple structural analysis model to predict the behavior of light‐frame buildings under lateral load. The model is limited to the racking response of shear walls that are arranged in a rectangular fashion beneath a rigid ceiling/floor diaphragm. Nonlinear load‐slip behavior of fasteners is utilized in an energy formulation to yield a three‐degree‐of‐freedom representation of each story of the building. Predicted behavior from the analysis model agrees favorably with results from full‐scale tests. The model provides a method for estimating the behavior of light‐frame buildings near lateral loading and should lead to realistic shear wall strength and stiffness requirements for both residential and commercial buildings.

Power flow analysis of simple structures

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The analysis of simple list structures

We present an analysis of simple lists, either sorted or unsorted, under the set of all their possible histories (i.e. evolutions considered up to order isomorphism) of length n. Using the theory of continued fractions and orthogonal polynomials, Flajolet, Françon, and Vuillemin have determined average costs of sequences of operations for many data structures of the dictionary or priority queue type. We show here that for the simplest structures variance estimates can also be obtained. The method uses continued fractions and properties of nonclassical q-generalizations of Hermite and Laguerre polynomials.

Finite difference calculations of dispersive Rayleigh wave propagation

This paper describes the method and results of the numerical modeling of Rayleigh wave propagation in media with velocity variations in both vertical and horizontal directions. The P-SV equations of motion in a general two-dimensional Cartesian elastic medium are approximated as second order finite difference equations. A second order free-surface condition is required to produce a noise-free solution. A band-limited pulse composed solely of the Rayleigh wave eigenfunctions for a uniformly layered medium is the initial condition. Numerical experiments simulating propagation in a plane layered structure allow greater accuracy in two station determination of Rayleigh wave phase velocities than that obtained in the field. In a medium with laterally varying velocities the numerical experiments include the local conversion of Rayleigh waves to higher modes and body waves and therefore model the contamination of phase velocity measurements by converted waves. As such, the numerical experiments simulate the seismic experiment conducted over a laterally varying structure under the restrictions that the structure is approximately two-dimensional and the illuminating wavefield crosses the structure perpendicularly to the structural strike. A sloping layer separating two waveguides of different thicknesses produced a minor directional dependence in Rayleigh wave phase velocities measured from updip and downdip traveling waves. The directional dependence is usually less than half that observed in numerical experiments of Love wave propagation in a similar structure. Analysis of several other simple structures leads to three conclusions. First, Rayleigh wave phase velocities measured over a region of lateral velocity variation exhibit small directional dependence unless the transition is very abrupt. Second, the dispersion measured across a laterally varying structure falls within or nearly within the bounds of the dispersion of the extreme plane layered structures derivable from the transition zone structure. Third, the numerical experiments indicate that the phase velocities measured across a slowly varying structure reflect the properties of the structure beneath the array.

Recognition of loop parallelisms by simulated execution

The method of recognition of loop parallelisms based on simulation of loop execution has been described, for the sake of simplicity, within the scope of simple loop structure analysis. At the same time, the method can be effectively extended to loops of arbitrary structures including loop nests. The method allows to vary the number of analyzed passes from N1 to N1×N2×...×Nj, where Ni is the number of iterations of a loop of an imbedding i. Reduction of a nest of loops to a loop of the form (1) can be carried out as follows.

Morphology analysis in localized crystal growth and dissolution

Procedures are developed in illustrated for analysis of the crystal shapes encountered in localized growth or dissolution. It is shown that with suitable modifications a Wulff-type construction can be applied to prediction of the shapes produced in selected area dissolution or growth at openings lithographically defined in an inert mask. Analysis of such shapes is particularly important in semiconductor processing technology, where precisely defined geometries must be produced, e.g., edges or walls of etched mesas. Although the procedures require knowledge of the dissolution or growth rate as a function of crystallographic orientation (polar diagrams), it is shown that in many cases sufficient information can be estimated from an analysis of simple test structures.

Estimating Earthquake Response of Simple Hysteretic Structures

This paper examines various methods for defining effective linear systems for the earthquake response analysis of simple hysteretic structures. A broad class of approximate methods is considered including: harmonic equivalent linearization, resonant amplitude matching, dynamic mass, constant critical damping, geometric stiffness, geometric energy, stationary random equivalent linearization, and average period and damping. A technique for estimating the accuracy of different approximate methods is presented. A new linearization scheme that may be applied to both degrading and nondegrading hysteretic systems is proposed.

Lateral Diagenesis in Monterey Shale, Santa Barbara Coast, California: ABSTRACT

Lateral differences in Monterey strata along the Santa Barbara coast indicate increased diagenesis toward the west. Westward, silica alters from biogenic amorphous opal (in diatom frustules) to diagenetic opal-CT, and then to diagenetic quartz. Continuous exposure for 50 km, simple homoclinal structure, paleogeographic setting, and detailed analysis of 14 stratigraphic sections together show that sediments were laterally equivalent, as originally deposited. Distinctive stratigraphic differences in sediment composition, informally divided into five members, are also laterally age-constant. Because silica phases differ in rocks of the same age, same depositional environment, and with identical bulk chemical composition, the differences must reflect post-depositional conditions. Overburden thicknesses and thermal changes in organic matter indicate that diagenesis increased westward owing to greater burial temperature. Study of sample sets taken laterally shows that both silica phase changes occurred by rapid solution-precipitation accompanied by significant compaction, and by little movement of silica between beds. Distinctive field characteristics (hardness, brittleness, bulk density, and luster) changed mainly during opal-CT formation. Although these changes affected rocks of nearly all compositions, details varied--even in carbonate-rich rocks--with the proportion of detrital material to biogenic or diagenetic silica. As this proportion increased, opal-CT formation was retarded, accompanying compaction decreased, ordering of opal-CT increased, and quartz formation was promoted. Nearly identical timing relation in associated calcareous, dolomitic, and carbonate-free rocks show that silica diagenesis was unaffected by carbonate except in rocks containing at least 10 times more silica than detrital material. End_of_Article - Last_Page 473------------

Fuzzy Set Theory For Dynamic Analysis WithUncertain Design Data

In this paper, theories of possibility and fuzzy sets are used for dynamic analysis of simple structures. The potentialities of possibility theory for analysis and design of engineering problems with uncertain data are first discussed. Possibility theory and fuzzy numbers are used to obtain upper and lower bounds for probability distributions and other statistical quantities, such as mean value intervals and upper and lower percentiles. The method is used to obtain the natural frequency of a simple structural systems constituted by the principal structure (frames, shear walls) and a number of nonstructural elements and infrastructures which are considered uncertainly defined and represented through fuzzy numbers. The aim of the study is to propose a technique to evaluate the influence of nonstructural elements on the dynamic response of multistorey buildings.

A SECOND APPROXIMATION FOR STABILITY ANALYSIS OF SIMPLE STRUCTURES

ABSTRACTStability analysis of simple structures usually involves a rather complicated transcendental system. Previous work has shown the usefulness of a first approximation of hyperbolic form. Herein it is demonstrated that a second approximation, leading in most cases merely to a quadratic equation, provides substantially greater accuracy and permits dealing with problems that do not yield to the first approximation. The argument is illustrated by two examples.

“La marquise sortit à cinq heures”

Simple structural analysis applied to passages cited from the works of André Breton elucidates the reasons for his condemnation of the statement La marquise sortit à cinq heures (see his Manifeste du surréalisme, 1924) as non-poetic. This study demonstrates the opposition existing between the above-mentioned realist sentence, essentially non-subjective (third-person subject), non-actual (past tense predicate), contextual (context can be supposed), and prosaic (lack of imagery), and on the other hand a theoretic surrealist sentence, essentially subjective (first-person subject), actual (present tense predicate), and non-contextual, producing a shock-image. In reality, Breton's surrealistic phrase does not always contain all of these qualities at once. However, in contrast to the condemned phrase which contains none at all, it does always manifest at least one of these characteristics, the most important having reference to the evocative power of the shock-image. A final comparison with a sentence quoted from Robbe-Grillet, the theoretician of the “nouveau roman”, proves that even though it may appear objective, the surrealist phrase is really not so. In conclusion, the four characteristics of the ideal surrealist sentence—subjectivity, actuality, non-contextuality, and ability to produce shock-images—create a poetics of discontinuity opposed to the classical art of narration as found traditionally in the novel. (In French)

Atomic Arrangement of Au(100) and Related Metal Overlayer Surface Structures. I

It has been shown, through analysis of simple overlayer structures consisting of a monolayer of Au or Ag on Cu(100) and Pd(100) surfaces, that Au atoms have an abnormal tendency to contract when positioned in a surface environment. This strong tendency for reduced interatomic spacing of Au surface layers is related to the atomically rearranged Au(100) surface, which consists of a hexagonal layer of Au atoms superimposed on a square array of substrate atoms. The driving force for rearrangement is interpreted in terms of the extreme sensitivity of the effective valency of Au to its atomistic environment. It is concluded that this interpretation of surface rearrangement is consistent with other unique properties of gold reported for binding energies of molecules in the vapor, and features of the band structure. In addition to providing information regarding the Au(100) surface structure, examination of metal overlayer structures has shown that pseudomorphism occurs during early growth stages of Ag and Au on the Pd(100) surface. Surface alloying of Au and Cu on the Cu(100) and on the Au (100) surfaces are also discussed.

Margins of safety for forces on the human dentition

Margins of safety for forces on the human dentition were derived on the basis of a maximum chewing force of 26 pounds. Margins of safety for adult women showed available chewing forces to be about 1 to 2 1/2 times greater than the maximum required chewing force. Adult men had values that were approximately 1 1/2 to 3 times greater than the maximum required chewing force. All adult teeth exhibited adequate reserves for chewing softer foods that require about 13 pounds of masticating force. The clinical importance of the margins of safety lies in their value for easy comparison of relative chewing merits of teeth and their potential to serve as abutments for prosthodontics. Anterior healthy teeth and periodontally involved teeth are shown as having poor chewing margins and poor abutment potential. The results support the use of posterior healthy teeth as abutments. The simple structural analysis of a fixed partial denture as a masticating unit revealed that its force capability complies with the biologically controlled chewing limits of the hosts abutment teeth. Accordingly, bridge (fixed partial dentures) forces are fixed by the abutment having lower load tolerances.

Ultimate load analysis of simple structures

The ultimate static load carrying capacity of a simple structure of ductile material, subjected to predominantly tensile stresses, is defined as the loading at which a tensile plastic instability occurs, analogous to necking in simple tension. A method of calculation of the critical loading for thin shells subjected to a uniform stress system is outlined. The strength determined in this way allows for the full strain-hardening capacity of the material, as contrasted with methods of estimating the yield point-load.

Total Neutron Scattering in Vitreous Silica

The structure of Corning superpure vitreous silica glass has been investigated with neutrons. A new method of analysis using variable neutron wavelengths and the measurement of total scattering cross sections from transmission experiments is developed and the results are compared with those from differential x-ray scattering. The total neutron scattering method permits a simple and direct structure analysis with resolution apparently superior to x-rays. The preliminary results compare well in a first approximation analysis with the basic structure model of Warren and others and in addition the neutron-determined atomic radial distribution curve exhibits some finer details than the x-ray results. Thermal inelastic scattering of neutrons was corrected for in an approximate way.