Software

ICAN/JAVA: Integrated Composite Analyzer Recoded in Java

The Integrated Composite Analyzer (ICAN) computer program, originally written in the FORTRAN language, has been completely recoded in Java to make it more widely usable. Whereas the original ICAN could be executed on only a limited number of platforms, ICAN/JAVA is compatible with almost all computers and operating systems. Moreover, whereas the original ICAN was applicable to only polymer-based composite materials containing circular fibers, ICAN/JAVA is applicable to diverse composites, including those that contain metal matrices, ceramic matrices, noncircular fibers, and/or particulate reinforcements. ICAN/JAVA can be used to simulate many aspects of the behavior and properties of a composite material and its constituent materials, including vibration-damping and electrical properties. The code includes provisions for three-way substructuring of fiber, interphase, and matrix constituents. Graphical output and telescoping of scale are available. The code includes an on-line user's manual. The Java Runtime Environment software, which can be downloaded free of charge for most platforms, is necessary for execution of ICAN/JAVA.

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Software for Multidisciplinary Analysis With Parallelization

HiMAP is an advanced, portable software system that implements highly modular, parallel computation of the possibly nonlinear, coupled behaviors of aeroelastic and other complex systems that comprise subsystems, each of which is modeled by use of software formulated within a separate technological discipline (e.g., fluid dynamics, structural dynamics, and controls). HiMAP is designed to be executed on massively parallel processors (MPPs) and workstation clusters based on a multiple-instruction, multiple-data architecture. Software for solving the differential equations of the fluids discipline (the Navier-Stokes equations) is parallelized according to a zonal approach; that of the structures discipline is parallelized according to a substructures approach. Computations within each discipline are spread across processors by use of a standard message-passing interface (MPI) for interprocessor communications. Computations that involve exchange of information among disciplines are parallelized by use of MPIAPI — a utility software library that flexibly allocates a group of processors and enables communication between processors within the same group or in different groups. Additional parallelization for multiple-parameter cases is implemented by use of a script software subsystem. The combined effect of the three levels of parallelization is an almost linear scaleability for multiple concurrent analyses performed efficiently on MPPs.

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Software for Monitoring Performance of Other Software

Performance Logging Services (PLS) is a software utility that tracks the performance of another program in terms of statistics of timing and use of memory buffers. The monitored program must utilize either the UNIX or the VxWorks operating system. PLS can monitor performance requirements in real time and uses minimal memory and central-processing-unit (CPU) resources. It can measure software timing events with an accuracy of less than 50 µs. PLS consists of (1) a library of application-program interfaces (APIs) and (2) a performance-control-tool subprogram. The APIs are incorporated into a program to be monitored by simply compiling them with the program code. During execution, the APIs update performance statistics in shared memory, to which an external program can gain access. An operator can use the performance-control tool to gain access to the statistics, reset the statistics, and set control limits (essentially, upper and lower limiting values of statistics). The performance-control tool includes a trigger that can be used to start another program when the control limits are exceeded. Data from the triggered program is used to find the source of timing glitches and/or otherwise assist in troubleshooting when performance requirements are out of specification.

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Analyzing Aeroelasticity in Turbomachines

ASTROP2-LE is a computer program that predicts flutter and forced responses of blades, vanes, and other components of such turbomachines as fans, compressors, and turbines. ASTROP2-LE is based on the ASTROP2 program, developed previously for analysis of stability of turbomachinery components. In developing ASTROP2-LE, ASTROP2 was modified to include a capability for modeling forced responses. The program was also modified to add a capability for analysis of aeroelasticity with mistuning and unsteady aerodynamic solutions from another program, LINFLX2D, that solves the linearized Euler equations of unsteady two-dimensional flow. Using LINFLX2D to calculate unsteady aerodynamic loads, it is possible to analyze effects of transonic flow on flutter and forced response. ASTROP2-LE can be used to analyze subsonic, transonic, and supersonic aerodynamics and structural mistuning for rotors with blades of differing structural properties. It calculates the aerodynamic damping of a blade system operating in airflow so that stability can be assessed. The code also predicts the magnitudes and frequencies of the unsteady aerodynamic forces on the airfoils of a blade row from incoming wakes. This information can be used in high-cycle-fatigue analysis to predict the fatigue lives of the blades.

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Numerical Modeling of Nanoelectronic Devices

Nanoelectronic Modeling 3-D (NEMO 3-D) is a computer program for numerical modeling of the electronic structure properties of a semiconductor device that is embodied in a crystal containing as many as 16 million atoms in an arbitrary configuration and that has overall dimensions of the order of tens of nanometers. The underlying mathematical model represents the quantum-mechanical behavior of the device resolved to the atomistic level of granularity. The system of electrons in the device is represented by a sparse Hamiltonian matrix that contains hundreds of millions of terms. NEMO 3-D solves the matrix equation on a Beowulf-class cluster computer, by use of a parallel-processing matrix×vector multiplication algorithm coupled to a Lanczos and/or Rayleigh-Ritz algorithm that solves for eigenvalues. In a recent update of NEMO 3-D, a new strain treatment, parameterized for bulk material properties of GaAs and InAs, was developed for two tight-binding submodels. The utility of the NEMO 3-D was demonstrated in an atomistic analysis of the effects of disorder in alloys and, in particular, in bulk InxGal–xAs and in In0.6Ga0.4As quantum dots.

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Code for Analyzing and Designing Spacecraft Power System Radiators

GPHRAD is a computer code for analysis and design of disk or circular-sector heatrejecting radiators for spacecraft power systems. A specific application is for Stirlingcycle/linear-alternator electric-power systems coupled to radioisotope general-purpose heat sources. GPHRAD affords capabilities and options to account for thermophysical properties (thermal conductivity, density) of either metal-alloy or composite radiator materials. GPHRAD also enables specification of a heat-pipe radiator design with a radial location of the embedded heat-pipe condenser section determined numerically so that minimum radiator area is obtained. Alternatively, the user can specify a radial location of the heat-pipe condenser section for easier assembly with other components. In this case, GPHRAD determines the tradeoff cost in increased radiator area for this choice. A third option is to design a radiator without heat pipes, with heat flowing radially outward from the cylindrical cold section of the Stirling power system. A major subroutine, TSCALC, calculates an equilibrium sink temperature for a radiator, taking account of the solar absorptivity and thermal emissivity of the radiator surface, the spacecraft-to-Sun distance expressed in astronomical units (AU), the angle at which solar radiation is incident on the radiator surface, and the view factor to space of the radiator surface and the infrared absorptivity-to-emissivity ratio for planetary thermal radiation, if any. The sink temperature, along with the heatsource temperature and properties of the radiator material, serve as inputs to the GPHRAD code, which then calculates dimensions of, and temperature distribution within the radiator for a required heatrejection load at given heat-rejection source temperature, such as the Stirling power system “cold” side temperature. The option to specify the disk tip-to-hub thickness ratio permits investigation of mass savings achieved by trapezoidal of parabolic tapering of the disk radiator design.

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Decision Support for Emergency Operations Centers

The Flood Disaster Mitigation Decision Support System (DSS) is a computerized information system that allows regional emergency-operations government officials to make decisions regarding the dispatch of resources in response to flooding. The DSS implements a real-time model of inundation utilizing recently acquired lidar elevation data as well asreal-time data from flood gauges, and other instruments within and upstream of an area that is or could become flooded. The DSS information is updated as new data become available. The model generates real-time maps of flooded areas and predicts flood crests at specified locations. The inundation maps are overlaid with information on population densities, property values, hazardous materials, evacuation routes, official contact information, and other information needed for emergency response. The program maintains a database and a Web portal through which real-time data from instrumentation are gathered into the database. Also included in the database is a geographic information system, from which the program obtains the overlay data for areas of interest as needed. The portal makes some portions of the database accessible to the public. Access to other portions of the database is restricted to government officials according to various levels of authorization. The Flood Disaster Mitigation DSS has been integrated into a larger DSS named REACT (Real-time Emergency Action Coordination Tool), which also provides emergency operations managers with data for any type of impact area such as floods, fires, bomb emergencies, and the like.

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