Tech Briefs

Timed Injection of Simulation Data via Redundant Network Ports in Time Triggered Ethernet (TTE) Systems

Lyndon B. Johnson Space Center, Houston, Texas Vehicle-scale integration and test requires closed-loop simulation using full-scale avionics systems or even entire vehicles. Incorporation of simulation data into real systems is problematic because real system sensors report the real laboratory environment, not the simulation environment. Past methods have attempted to simulate the physical sensors, or have added simulation interfaces to the flight sensor electronics. Both approaches are intrusive and costly to incorporate in an actual flight system design. The first approach requires dozens to hundreds of contact points between the vehicle and the simulation hardware. The second approach adds complexity, cost, and failure modes to the flight system hardware and firmware.

Posted in: Briefs, TSP

Read More >>

Method of Performing Computational Aeroelastic Analyses

Langley Research Center, Hampton, Virginia When designing aerodynamic structures, it is important to understand if, and under what aerodynamic conditions, the structure will be stable and unstable. This is especially true if a structure is inherently flexible, such as a wing, where unstable response leads to oscillations of the structure until failure occurs. Since structure design generally includes performance predictions, it is necessary to predict the aeroelastic response of a particular design. To do this, computational aeroelastic methods are used to simulate numerically an aeroelastic process using computational techniques that include the use of Computational Fluid Dynamics (CFD) codes. The value of the information generated by traditional CFD-based computational aeroelastic analyses is limited in that it can require a significant level of computational resources to generate and cannot be readily utilized by other disciplines involved in the overall vehicle design process.

Posted in: Briefs

Read More >>

Graphical Acoustic Liner Design and Analysis Tool

Langley Research Center, Hampton, Virginia The Interactive Liner Impedance Analysis and Design (ILIAD) tool is a software package used to design the composite surface impedance of an acoustic liner using resonant channels. ILIAD’s graphical user interface allows the acoustic channel geometry to be drawn in the liner volume while the surface impedance and absorption coefficient calculations are updated in real time. A one-dimensional transmission line model serves as the basis for the impedance calculation and can be applied to many liner configurations. The software can be used to design arrays of resonators that can be packaged into complex geometries heretofore unsuitable for effective acoustic treatment.

Posted in: Briefs

Read More >>

Open Vehicle Sketch Pad

Langley Research Center, Hampton, Virginia The conceptual aircraft designer is faced with a dilemma on how to strike the best balance between productivity and fidelity. Attempts have been made to use computer-aided design packages to fill this void, but their cost and steep learning curve have made them unwieldy at best. Open Vehicle Sketch Pad (OpenVSP.org) has been developed over several years to better fill this void. While no substitute for the full feature set of computer-aided design packages, Open VSP allows even novices to quickly become proficient in defining three-dimensional, watertight aircraft geometries that are adequate for producing multi-disciplinary metamodels for higher order analysis methods, wind tunnel and display models, as well as a starting point for animation models.

Posted in: Briefs

Read More >>

Thermal Spraying of Coatings Using Resonant Pulsed Combustion

This is a high-volume, high-velocity surface deposition of protective metallic and other coatings on surfaces. John H. Glenn Research Center, Cleveland, Ohio Thermal spray coating is not a new process. There are different techniques utilized that depend on the objective function of the coating, the environment to which the coated piece will be subjected, and the coating material used. In any application, quality is ultimately measured by how well the coating material adheres to the sprayed surface. This, in turn, is controlled by the velocity at which the coating material impinges on the substrate, the size of the molten coating particles, and the degree to which the coating material is prevented from chemically reacting while in a molten state.

Posted in: Briefs, TSP

Read More >>

Plasma Treatments to Assist Fluid Manipulation in Microgravity

Altering the surface energy of container walls permits anchoring of fluids within the container. Lyndon B. Johnson Space Center, Houston, Texas A recent innovation has made manipulation of hazardous laboratory reagents in microgravity easier, thus enabling even more scientific research to be performed on the International Space Station (ISS). Prior to this innovation, moving fluids from container to container was performed only under conditions of redundant and physically separate layers of containment. This design paradigm restricts access to — and direct manipulation of — fluids in microgravity conditions.

Posted in: Briefs

Read More >>

Stencil-less Jet Printing for PCB Assembly

Solder paste inkjet is an inline, solder-mask printing technology that enables 3D printing of different thicknesses of solder paste for prototype PCBs. Imagineering Inc., Elk Grove Village, Illinois For many years, stencil printing has been the standard method of depositing solder paste on surface mount assembly printed circuit boards (PCBs). It has provided a durable method of applying solder paste, but there were always difficulties that significantly slowed down a change from one product to another in the assembly operation, and added cost. A significant challenge in newer, smaller electronics assembly is the huge difference in size among components. Therefore, trying to apply the right amount of solder paste for each component with one stencil is difficult. The biggest problem is how to produce quick-turn prototypes without disrupting series production that is already running in the line. Product changeover requires time-consuming tweaks to the stencil printing process, while unnecessarily shutting down an expensive assembly line to change the product. The inability of the stencil’s technology to vary solder paste volume by part, on the run, remains the biggest impact on the soldering quality.

Posted in: Briefs

Read More >>