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New Methods to Update Finite Element Meshes Rapidly

This presentation discusses modern methods to update existing FEM models significantly faster than before. The methods discussed are applicable to thin structures that can be readily represented as shell FE meshes. The specialized meshing capabilities of MSC Apex will be highlighted and demonstrated on a sample part.

Posted in: On-Demand Webinars

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Designing Reliable Plastic Parts with Process-Driven Simulation Methods

Many industries are benefiting in 'lightweighting' efforts by using innovative composite materials like reinforced plastics. Successful design of plastic parts for structural performance requires greater insight into the manufacturing process and behavior of the materials early in the design cycle.

Posted in: On-Demand Webinars

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Expediting the Process of TET Meshing Highly Complex Solid Geometry for FEA

Meshing solid geometry with tetrahedral elements is a quick way of creating finite element models, but is not without its challenges. In some cases, solid geometry cannot be successfully meshed by the most advanced tetrahedral mesher. In many other cases, a tetrahedral mesh is produced, but is composed of poorly distorted elements that are inadequate for finite element analysis.

Posted in: On-Demand Webinars

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Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA)

John H. Glenn Research Center, Cleveland, Ohio The current steady-state performance-based system studies are not adequate to evaluate certain advanced technologies for the challenges associated with meeting the transient performance requirements without better definition and control of component operating margins. Additional dynamic analyses would require more detailed, physics-based, component-level models and controllers in order to better identify dynamic issues that may arise during operation of the engine. The additional complexity in these models increases the effort necessary throughout the design processes, including the system-analysis step. The solution would be a physics-based engine model with full envelope controller. C-MAPSS and C-MAPSS40k are examples of engine models with full envelope controllers, but because they are designed to model a specific engine, they are not good candidates for systems analysis.

Posted in: Briefs, TSP, Electronics & Computers

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Wald Sequential Probability Ratio Test for Space Object Conjunction Assessment

The decision procedure is based on targets for false alarm and missed detection rates, along with a prior assessment of the risk of collision, which is independent of the orbit determination. Goddard Space Flight Center, Greenbelt, Maryland When a maneuverable spacecraft confronts a potentially unsafe conjunction with another space object, its operators must decide whether to maneuver to mitigate the risk of a collision. Such decisions may not be straightforward, since the operators must balance their confidence in the predictions that detected the conjunction, the actual likelihood of a collision, any risk inherent in performing the maneuver, interruptions to the mission’s ongoing operations, and long-term consequences such as depletion of consumable propellant. The most common metric for assessing the risk associated with a conjunction is the collision probability.

Posted in: Briefs, Electronics & Computers

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Next Generation of 3DGRAPE: Flexible Framework for Hypersonic Navier-Stokes Shuttle Orbiter Meshes

High-fidelity grids were generated rapidly using an assembly line approach with teamwork among NASA centers. Langley Research Center, Hampton, Virginia The class of 3DGRAPE codes is designed to generate volume grids using iterative methods to solve the non-linear, nonhomogeneous, elliptic partial differential heat equation with heat sources. The solution to the heat equation develops three-dimensional discrete points within a domain outside or inside a vehicle where fluid flow is simulated with Computational Fluid Dynamics (CFD). The latest version in this class of software is the 3DGRAPE/AL:V3, version 3 of the Three-Dimensional Grids about Anything by Poisson’s Equation with Upgrades from NASA Ames and Langley computer programs. The previous version, 3DGRAPE/AL:V2 [“Further Improvement in 3DGRAPE,” (LAR-16415-1) NASA Tech Briefs, Vol. 28, No. 9 (September 2004), p. 50], was advanced through the development of a new block-to-block boundary condition that guarantees C-I continuity between adjacent blocks sharing a common block face. Until this condition was developed, matching block faces were only created by projecting a straight line from one cell into each block from the matching face, thereby changing the initial grid that defines a structured multiple block system.

Posted in: Briefs, TSP, Electronics & Computers

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Delay Tolerant Link State Routing MACHETE Model

NASA’s Jet Propulsion Laboratory, Pasadena, California This software models the Delay Tolerant Link State Routing protocol. It runs inside the QualNet network simulator, and allows injecting of external bundles when running in emulation mode. It leverages QualNet’s library of networking protocols and JPL’s CCSDS models.

Posted in: Briefs, Electronics & Computers

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