707 research outputs found
The NASTRAN theoretical manual (level 16.0)
The manual is a commentary on the NASTRAN computer program, introducing the program to all interested persons. The manual's most important function is to present the developments of the analytical and numerical procedures that underlie the program. This manual is one of the four manuals which document the NASTRAN computer program
The NASTRAN theoretical manual
Designed to accommodate additions and modifications, this commentary on NASTRAN describes the problem solving capabilities of the program in a narrative fashion and presents developments of the analytical and numerical procedures that underlie the program. Seventeen major sections and numerous subsections cover; the organizational aspects of the program, utility matrix routines, static structural analysis, heat transfer, dynamic structural analysis, computer graphics, special structural modeling techniques, error analysis, interaction between structures and fluids, and aeroelastic analysis
Spherical Earth analysis and modeling of lithospheric gravity and magnetic anomalies
A comprehensive approach to the lithospheric analysis of potential field anomalies in the spherical domain is provided. It has widespread application in the analysis and design of satellite gravity and magnetic surveys for geological investigation
Researches on Non-standard Optics for Advanced Gravitational Waves Interferometers
This thesis presents a collection of different researches on non-standard
optics in view of enhancing the performances of the Advanced Gravitational
waves interferometric detectors, where the thermal noise of the test masses is
expected to be a limiting factor for their sensitivity.
We provide a quantitative analysis of the impact of non-Gaussian beams on
different kinds of thermal noises. We developed the theory of mesa beam, in
view of a future implementation in advanced GW interferometers of the mesa beam
idea, focusing on the analytical derivation of the quantities (i.e. beam width,
divergence, propagation factor), which are chosen as ISO standard reference
parameters for the characterization of an optical beam. We also analytically
proved a new duality relation between optical cavities with non-spherical
mirrors. The interest of the GW community in this new beam technology led us to
the construction and testing of a prototype mesa beam Fabry-Perot cavity with
Mexican-hat mirror. Part of the work of this thesis was devoted to the
development of new simulation programs of optical systems. These programs
provided the theoretical expected behaviour of our experiment, in particular
cavity modes structure and misalignments sensitivity to be confronted with the
experimental results. We also explored another complementary way of reducing
the mirror thermal noise, beside the beam shaping, that is the multi-layered
coating thickness optimization. We show it to be effective in reducing the
coating noise and explore the possible implications for GW interferometers in
terms of sensitivity. During this analysis we developed an independent model
for the coating effective elastic parameters, which is based on the well
understood subject of homogenization theory.Comment: Ph.D. thesis, University of Pisa & LIGO-Caltech, 185 page
Refresher course in maths and a project on numerical modeling done in twos
These lecture notes accompany a refresher course in applied mathematics with a focus on numerical concepts (Part I), numerical linear algebra (Part II), numerical analysis, Fourier series and Fourier
transforms (Part III), and differential equations (Part IV). Several numerical projects for group work are provided in Part V. In these projects, the tasks are threefold: mathematical modeling, algorithmic design, and implementation. Therein, it is important to draw interpretations
of the obtained results and provide measures (Parts I-IV) how to build confidence into numerical findings such intuition, error analysis, convergence analysis, and comparison to manufactured solutions. Both authors have been jointly teaching over several years this class and
bring in a unique mixture of their respective teaching and research fields
Coupled structural, thermal, phase-change and electromagnetic analysis for superconductors, volume 1
This research program has dealt with the theoretical development and computer implementation of reliable and efficient methods for the analysis of coupled mechanical problems that involve the interaction of mechanical, thermal, phase-change and electromagnetic subproblems. The focus application has been the modeling of superconductivity and associated quantum-state phase-change phenomena. In support of this objective the work has addressed the following issues: (1) development of variational principles for finite elements; (2) finite element modeling of the electromagnetic problem; (3) coupling of thermal and mechanical effects; and (4) computer implementation and solution of the superconductivity transition problem. The research was carried out over the period September 1988 through March 1993. The main accomplishments have been: (1) the development of the theory of parametrized and gauged variational principles; (2) the application of those principled to the construction of electromagnetic, thermal and mechanical finite elements; and (3) the coupling of electromagnetic finite elements with thermal and superconducting effects; and (4) the first detailed finite element simulations of bulk superconductors, in particular the Meissner effect and the nature of the normal conducting boundary layer. The grant has fully supported the thesis work of one doctoral student (James Schuler, who started on January 1989 and completed on January 1993), and partly supported another thesis (Carmelo Militello, who started graduate work on January 1988 completing on August 1991). Twenty-three publications have acknowledged full or part support from this grant, with 16 having appeared in archival journals and 3 in edited books or proceedings
Research in structural and solid mechanics, 1982
Advances in structural and solid mechanics, including solution procedures and the physical investigation of structural responses are discussed
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