415 research outputs found
ELAS8 - Computer program for linear structure equilibrium problems
Program generates and solves governing equations for unknown deflection of mesh points as if problem were to locate stationary point of total potential function associated with given loading and unknown deflections. Solution is obtained by means of displacement method and finite element technique
Computation of stresses in triangular finite elements
Stress calculations in linear thin shells of aeolotropic material using deflections obtained by finite element metho
On the impact induced stress waves in long bars
Impact induced stress waves in long bars using characteristic method of solutio
ELAS - A general purpose computer program for the equilibrium problems of linear structures
Digital computer program ELAS handles the equilibrium problems of linear structures of one, two, or three dimensional continuum. ELAS generates the governing equations for the unknown deflections of the mesh points that define the stationary point of the total potential energy function associated with the given loading and unknown deflections
ELAS - A general purpose computer program for the equilibrium problems of linear structures. Volume 1 - User's manual
ELAS general purpose digital computer program for equilibrium problems of linear structure
Behavior of triangular shell element stiffness matrices associated with polyhedral deflection distributions
Stiffness matrices derived for triangular shell elements associated with polyhedral deflection distribution
Pressure distribution in a hydrostatic bearing of multi-wells
Pressure distribution in hydrostatic bearing of multi-wells obtained by use of Navier-Stokes equation
ELAS: A general-purpose computer program for the equilibrium problems of linear structures. Volume 2: Documentation of the program
A general purpose digital computer program for the in-core solution of linear equilibrium problems of structural mechanics is documented. The program requires minimum input for the description of the problem. The solution is obtained by means of the displacement method and the finite element technique. Almost any geometry and structure may be handled because of the availability of linear, triangular, quadrilateral, tetrahedral, hexahedral, conical, triangular torus, and quadrilateral torus elements. The assumption of piecewise linear deflection distribution insures monotonic convergence of the deflections from the stiffer side with decreasing mesh size. The stresses are provided by the best-fit strain tensors in the least squares at the mesh points where the deflections are given. The selection of local coordinate systems whenever necessary is automatic. The core memory is used by means of dynamic memory allocation, an optional mesh-point relabelling scheme and imposition of the boundary conditions during the assembly time
Mechanically Compliant Grating Reflectors for Optomechanics
We demonstrate micromechanical reflectors with a reflectivity as large as
99.4% and a mechanical quality factor Q as large as 7.8*10^5 for optomechanical
applications. The reflectors are silicon nitride membranes patterned with
sub-wavelength grating structures, obviating the need for the many dielectric
layers used in conventional mirrors. We have employed the reflectors in the
construction of a Fabry-Perot cavity with a finesse as high as F=1200, and used
the optical response to probe the mechanical properties of the membrane. By
driving the cavity with light detuned to the high-frequency side of a cavity
resonance, we create an optical antidamping force that causes the reflector to
self-oscillate at 211 kHz
Differentially Private Linear Optimization for Multi-Party Resource Sharing
This study examines a resource-sharing problem involving multiple parties
that agree to use a set of capacities together. We start with modeling the
whole problem as a mathematical program, where all parties are required to
exchange information to obtain the optimal objective function value. This
information bears private data from each party in terms of coefficients used in
the mathematical program. Moreover, the parties also consider the individual
optimal solutions as private. In this setting, the concern for the parties is
the privacy of their data and their optimal allocations. We propose a two-step
approach to meet the privacy requirements of the parties. In the first step, we
obtain a reformulated model that is amenable to a decomposition scheme.
Although this scheme eliminates almost all data exchanges, it does not provide
a formal privacy guarantee. In the second step, we provide this guarantee with
a locally differentially private algorithm, which does not need a trusted
aggregator, at the expense of deviating slightly from the optimality. We
provide bounds on this deviation and discuss the consequences of these
theoretical results. We also propose a novel modification to increase the
efficiency of the algorithm in terms of reducing the theoretical optimality
gap. The study ends with a numerical experiment on a planning problem that
demonstrates an application of the proposed approach. As we work with a general
linear optimization model, our analysis and discussion can be used in different
application areas including production planning, logistics, and revenue
management
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