Structures and Mechanisms
Structures and Mechanisms
Deployables, Structural Loading Analysis and Design
CCGEOM is a Fortran computer code developed to facilitate the rapid generation of the flow passage and blading for various turbomachinery components.
U.S. Release Only
RANSTEP - Reduced order Analysis using a Nonlinear STiffness Evaluation Procedure
A new implementation of reduced order finite-element-based analysis for solving geometrically nonlinear random vibration problems of complex structures has been developed. The implementation is given the acronym RANSTEP for Reduced order Analysis using a Nonlinear STiffness Evaluation Procedure. The nonlinear stiffness evaluation procedure allows computation of otherwise inaccessible modal nonlinear stiffness terms from commercial finite element programs. Some operations are performed outside the commercial codes and utilize in-house developed FORTRAN codes. Additionally Direct Matrix Abstraction Program (DMAP) alters and PYTHON scripts are used to facilitate implementations written about MSC.NASTRAN and ABAQUS, respectively. Two solutions procedures of different fidelity and computational cost are offered in each implementation. They are equivalent linearization and time numerical simulation. Aerospace uses include aircraft and spacecraft structural analysis.
U.S. Release Only
Tool for Generation of MAC/GMC Representative Unit Cell for CMC/PMC Analysis
This is a Graphics user interface (GUI) based tool that generates a number of different user-defined repeating unit cells (RUCs) interactively that can be used in conjunction with the composite micromechanics based analysis tool MAC GMC and HF GMC.In addition, the code has provisions for generation of a MAC/GMC-compatible input text file that can be merged with any MAC/GMC input file tailored to analyze composite materials. Although the primary intention was to address the three different constituents and phases that are usually present in CMCsnamely, fibers, matrix, and interphaseit can be easily modified to address two-phase polymer matrix composite (PMC) materials where an interphase is absent. Currently, the tool capability includes generation of RUCs for square packing, hexagonal packing, and random fiber packing as well as RUCs based on actual composite micrographs. All these options have the fibers modeled as having a circular cross-sectional area. In addition, a simplified version of RUC is provided where the fibers are treated as having a square cross section and are distributed randomly.
U.S. Release Only
Femera is an open-source finite element Mini-App, developed under LaRC's High Performance Computing Incubator (HPCI), that updates the element-by-element (EBE) matrix-free method for modern HPC architectures, The purpose of a Mini-App is to isolate the most intensive part of a code for release so it can be optimized through collaboration. This Mini-App isolates EBE iteration kernels, with tests for correctness and performance, for use across a wide range of problem sizes and HPC architectures.
Half-Cycle Crack Growth Predicts Operational Flight Life of Critical Aerostructural Components
<p>This software program offers a reliable method for calculating theoretical fatigue crack growths that could lead to catastrophic structural component failures. The program builds upon and integrates Armstrong's proven half-cycle and closed-form aging theories and is especially accurate because it considers every half-cycle of loading spectra for specific structural components. This innovation is an improvement on traditional prediction software (and in particular on visual inspections) because it considers mini-amplitude stress loading and half-cycles based on the duty cycle of a particular component or structure.</p> <p>Developed to calculate the number of operational life flights for B-52B pylon hooks, the program and underlying theories can be applied to estimate the service life of any critical structural component. </p> <p>BENEFITS</p> <p> * Reliable: Predicts operational flight life of critical aerostructural components</p> <p> * Accurate: Considers a comprehensive suite of test data by counting every half-cycle of each random loading spectrum, including secondary mini-amplitude half-cycles that do not cross mean stress lines</p> <p> * Customized: Identifies potential structural problem areas and calculates the number of safe flights an aerostructure can make based on its particular duty cycle</p> <p> * Economical: Saves monetary costs associated with loss of expensive equipment due to component failures</p> <p> * Adaptable: Offers applicability to other industries, with modifications to the input model</p> <p>POTENTIAL APPLICATIONS</p> <p> * Spacecraft</p> <p> * Aircraft</p> <p> * Ships</p> <p> * Oil rigs</p> <p> * Windmills </p> <p> * Bridges</p> <p> * Oscillating industrial equipment used in mines and quarries</p> <p>HOW IT WORKS</p> <p>The Half-Cycle Crack Growth Computer Program is a powerful and practical tool for visualizing crack growth curves associated with critical stress points. It was designed to determine the number of safe operational flights an aircraft can make without structural component failures due to fatigue crack growth. The computer program was developed after two rear B-52B pylon hooks failed simultaneously during an Armstrong test operation. Subsequent examinations revealed that hook failure was caused by rapid crack propagation from existing micro cracks that had been masked by chrome-plated surfaces and thus were undetected during visual inspections.</p> <p>To obtain baseline data for use in the program, the critical structural components must be proof-load tested to determine the initial theoretical crack size based on fracture mechanics. Next, strain gauges are installed in the vicinity of stress concentration points and are calibrated to record the applied loads. After the failure-critical components are identified, stress analysis is performed for each component to establish the functional relationship between the applied load and the induced tangential stress at the critical stress point. The program reads the data and selects the maximum and minimum loads of each half-cycle of the random flight loading spectra. Program outputs are used to generate and display crack growth curves, providing a visual warning for preventing catastrophic structural failures.</p> <p>For the B-52B pylon hooks discussed above, crack growth curves were produced for each hook, allowing visual observation of the crack growth behavior during the entire air-launching or captive flight. The crack growth curves provided the visual knowledge that taxiing, takeoff, drop/landing, and sometimes gusts induced a major portion of the total crack growth per operation.</p> <p>Written in the C programming language, the program can be adapted for use in other industries by modifying the input model (i.e., data format load spectrum files) for the most expensive and mission critical components.</p> <p>WHY IT IS BETTER</p> <p>The program examines test data in a much more detailed fashion than other fatigue crack growth modeling software, counting every half-cycle of each random loading spectrum, so it is able to make better predictions about component life. By improving fatigue and failure predictions, the software provides safer flights and lower maintenance costs. Additionally, these predictions allow engineers to determine the critical points during operation that the majority of stress is placed on a particular component, which could allow for better component design that takes those specific forces into account.</p>
General Public Release
Structure Deformation Calculation Program based on Ko Displacement Transfer Functions
The Structure Deformation Calculation Program is a computer program that will calculate slopes, deflections, and cross-sectional twist angles if applicable at strain-sensing stations on any structures based on the Ko Displacement Transfer Functions. By using this method, only a small number of strain sensors are required along strain-sensing line(s) on a structure. The program uses measured surface bending strains obtained at strain-sensing stations and structure geometrical properties as its inputs. Depending on structure type, the program will use the appropriate Ko Displacement Transfer Function. All structure types mentioned in the publications listed in the Technology Readiness / Software tab are covered in this program. The figures of different structure types will be included in the Additional Documentation in the General Information tab. The Displacement Theory is purely geometrical in nature, containing no material properties. The program will output time history slopes, deflections, maximum deflections, and cross-sectional twist angles if applicable, and depth factors if calculated. Users can use the time history deflections for plotting: deformed shapes of the structure at a certain time slice, three dimensional deformed shapes at multiple time slices, and deflections of each individual strain-sensing station. The calculated deflections of a structure can be studied and analyzed for monitoring the health of a structure to prevent catastrophic events.
General Public Release
This MATLAB routine generates a scalable finite element model suitable for hybrid wing-body (HWB) structural analysis and optimization. HWB geometry structure is based on a vehicle sketch-pad (VSP) surface model of an aircraft and a FLOPS-compatible parameterization of the center body and wing structure. Optimization and weight calculation are based on a Nastran finite element analysis of the primary structural components.
U.S. Release Only
Automate Optimization and Design Tasks Across Disciplines with Object-Oriented Optimization Tool 2.0
<p>This multidisciplinary design analysis and optimization (MDAO) solution automates optimization tasks early in the design process according to a range of user-defined parameters, including factors such as cost, safety, and environmental impact. The tool provides a framework that enables several engineers to use multiple programs to globally optimize a model.</p> <p>This tool quickly streamlines optimization and design tasks by integrating disparate software packages--NASTRAN®, ZAERO®, Cart3D, FUN3D, MOMAT, etc.--in a cross-platform network environment. Designers can convert design variables to structural parameters and generate objective functions using either the built-in pre/post-processor or their own analyzer.</p> <p>FEATURES</p> <p> * Central executive module allows designers to choose input/output files and solution modules, determine the status of tasks, and select modules for output viewing and filtering.</p> <p> * Object-oriented framework integrates the analysis codes for multiple disciplines, rather than relying on one code to perform the analysis for all disciplines.</p> <p> * Modules calculate structural weight, stress, deflection, buckling, and more.</p> <p> * Graphical user interface can provide a single point of control for applications that run on a user's PC or for code that may reside on remote workstations or a computational cluster.</p> <p> * Use of existing tools and practices saves development time and resources.</p> <p> * With most of the code written in standard Fortran, it is easy to upgrade and incorporate new optimization technologies while integrating/adopting new state-of-the-art software.</p> <p>POTENTIAL APPLICATIONS</p> <p>Originally developed for preliminary design of subsonic, transonic, supersonic, and hypersonic aircraft, this innovative MDAO tool can be applied to other engineering fields, including:</p> <p> * Shipbuilding</p> <p> * Automotive</p> <p> * Engineering services</p> <p> * Packaging</p> <p> * Sporting equipment</p> <p>NASTRAN is a registered trademark of the National Aeronautics and Space Administration. ZAERO is a registered trademark of ZONA Technology, Inc.</p>
General Public Release
ScIFEN Solver Mini-App (HPCI)
This technology is simply a stripped down version of a previously released code to create an open source Mini-App for LaRC's High Performance Computing Incubator (HPCI). The purpose of a Mini-App is to isolate the most intensive part of a code for release so it can be optimized through collaboration. ScIFEN is a code for solving large scale computational materials and structures problems using the finite element method. This Mini-App isolates the linear solver that ScIFEN uses and loads an example system from file as a test case. It represents roughly 1% of the total source code.
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