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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
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NASA NTRS2018

Determination of Ballistic Limit for IM7/8552 Using Peridynamics

Significant testing is required to design and certify primary aircraft structure subject to High Energy Dynamic Impact (HEDI) events; current work under the NASA Advanced Composites Consortium (ACC) HEDI Project seeks to determine the state-of-the-art of dynamic fracture simulations for composite structures in these events. This paper discusses one of four Progressive Damage Analysis (PDA) methods selected for this project: peridynamics, through EMU implementation. A brief discussion of peridynamic theory is provided, followed by an outline of ballistic impact testing performed for model development and assessment. Detailed modeling approach and test-analysis correlation for a single open test case are presented, followed by the results of a series of blind predictions made prior to testing and test-analysis correlation performed with measured NASA test results. Specifically, we present simulation results for the ballistic limit (V50) of IM7/8552 composite panels ballistically tested with an impactor representative of a high-velocity fan-blade-out condition. In particular, force and displacement history and the damage state determined analytically are compared to measured results. Ultimately, peridynamics has the ability to predict damage patterns, impact force and deflections during a high energy dynamic impact event on composite panels of different layups using two different types of impactors. Blind predictions were promising and increased confidence in the model for impact simulation. There are open questions regarding the fidelity of the test fixture idealization in regards to stiffness and damping which will need to be addressed in future work.

Cuenca, Fernando↗
NASA NTRS2013

Determine ISS Soyuz Orbital Module Ballistic Limits for Steel Projectiles Hypervelocity Impact Testing

A new orbital debris environment model (ORDEM 3.0) defines the density distribution of the debris environment in terms of the fraction of debris that are low-density (plastic), medium-density (aluminum) or high-density (steel) particles. This hypervelocity impact (HVI) program focused on assessing ballistic limits (BLs) for steel projectiles impacting the enhanced Soyuz Orbital Module (OM) micrometeoroid and orbital debris (MMOD) shield configuration. The ballistic limit was defined as the projectile size on the threshold of failure of the OM pressure shell as a function of impact speeds and angle. The enhanced OM shield configuration was first introduced with Soyuz 30S (launched in May 2012) to improve the MMOD protection of Soyuz vehicles docked to the International Space Station (ISS). This test program provides HVI data on U.S. materials similar in composition and density to the Russian materials for the enhanced Soyuz OM shield configuration of the vehicle. Data from this test program was used to update ballistic limit equations used in Soyuz OM penetration risk assessments. The objective of this hypervelocity impact test program was to determine the ballistic limit particle size for 440C stainless steel spherical projectiles on the Soyuz OM shielding at several impact conditions (velocity and angle combinations). This test report was prepared by NASA-JSC/ HVIT, upon completion of tests.

Lyons, Frankel↗
NASA NTRS1974

Nonlinear parameter identification: Ballistic range experience applicable to flight testing

The parameter identification scheme being used is a differential correction least squares procedure (Gauss-Newton method). The position, orientation, and derivatives of these quantities with respect to the parameters of interest (i.e., sensitivity coefficients) are determined by digital integration of the equations of motion and the parametric differential equations. The application of this technique to three vastly different sets of data is used to illustrate the versatility of the method and to indicate some of the problems that still remain.

Chapman, G.↗
NASA NTRS1985

ICIASF '85 - International Congress on Instrumentation in Aerospace Simulation Facilities, 11th, Stanford University, CA, August 26-28, 1985, Record

Developments related to laser Doppler velocimetry are discussed, taking into account a three-component dual beam laser-Doppler-anemometer to be operated in large wind tunnels, a new optical system for three-dimensional laser-Doppler-anemometry using an argon-ion and a dye laser, and a two-component laser Doppler velocimeter by switching fringe orientation. Other topics studied are concerned with facilities, instrumentation, control, hot wire/thin film measurements, optical diagnostic techniques, signal and data processing, facilities and adaptive wall test sections, data acquisition and processing, ballistic instrument systems, dynamic testing and material deformation measurements, optical flow measurements, test techniques, force measurement systems, and holography. Attention is given to nonlinear calibration of integral wind tunnel balances, a microcomputer system for real time digitized image compression, and two phase flow diagnostics in propulsion systems.

Source record↗
NASA NTRS1976

Airborne ballistic camera tracking systems

An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

Redish, W. L.↗
NASA NTRS1988

A research study for the preliminary definition of an aerophysics free-flight laboratory facility

A renewed interest in hypervelocity vehicles requires an increase in the knowledge of aerodynamic phenomena. Tests conducted with ground-based facilities can be used both to better understand the physics of hypervelocity flight, and to calibrate and validate computer codes designed to predict vehicle performance in the hypervelocity environment. This research reviews the requirements for aerothermodynamic testing and discusses the ballistic range and its capabilities. Examples of the kinds of testing performed in typical high performance ballistic ranges are described. We draw heavily on experience obtained in the ballistics facilities at NASA Ames Research Center, Moffett Field, California. Prospects for improving the capabilities of the ballistic range by using advanced instrumentation are discussed. Finally, recent developments in gun technology and their application to extend the capability of the ballistic range are summarized.

Canning, Thomas N.↗
NASA NTRS1972

Analysis of flight test transition and turbulent heating data. Part 1: Boundary layer transition results

The objective of the study was to provide a detailed post flight evaluation of ballistic vehicle flight test boundary layer transition data. A total of fifty-five vehicles were selected for analysis. These vehicles were chosen from a data sampling of roughly two hundred flights and the criteria for vehicle selection is delineated herein. The results of the analysis indicate that frustum transition of re-entry vehicles appears to be nose tip dominated. Frustum related parameters and materials apparently have a second order effect on transition. This implies that local viscous parameters on the frustum should not correlate flight test transition data, and in fact they do not. Specific parameters relative to the nose tip have been identified as the apparent dominant factors that characterize the transition phenomena and a correlation of flight test data is presented.

Martellucci, A.↗
NASA NTRS1973

Atmosphere-entry behavior of a modular, disk-shaped, isotope heat source.

The authors have studied the entry and impact behavior of an isotope heat source for space nuclear power that disassembles into a number of modules which would enter the earth's atmosphere separately if a flight aborted. These modules are disk-shaped units, each with its own reentry heat shield and protective impact container. In normal operation, the disk modules are stacked inside the generator, but during a reentry abort they separate and fly as individual units of low ballistic coefficient. Flight tests at hypersonic speeds have confirmed that a stack of disks will separate and assume a flat-forward mode of flight. Free-fall tests of single disks have demonstrated a nominal impact velocity of 30 m/sec at sea level for a practical range of ballistic coefficients.

Vorreiter, J. W.↗
NASA NTRS2015

Impact Behavior of Composite Fan Blade Leading Edge Subcomponent with Thermoplastic Polyurethane Interleave

Impact damage tolerance and damage resistance is a critical metric for application of polymer matrix composites where failure caused by impact damage could compromise structural performance and safety. As a result, several materials and/or design approaches to improve impact damage tolerance have been investigated over the past several decades. Many composite toughening methodologies impart a trade-off between increased fracture toughness and compromised in-plane strength and modulus. In large part, mechanical tests to evaluate composite damage tolerance include static methods such as Mode I, Mode II, and mixed mode failures. However, ballistic impact damage resistance does not always correlate with static properties. The intent of this paper is to evaluate the influence of a thermoplastic polyurethane veil interleave on the static and dynamic performance of composite test articles. Static coupon tests included tension, compression, double cantilever beam, and end notch flexure. Measurement of the resistance to ballistic impact damage were made to evaluate the composites response to high speed impact. The interlayer material showed a decrease of in-plane performance with only a moderate improvement to Mode I and Mode II fracture toughness. However, significant benefit to impact damage tolerance was observed through ballistic tests.

Damage Tolerance↗
NASA NTRS2014

Ballistic Performance Model of Crater Formation in Monolithic, Porous Thermal Protection Systems

Porous monolithic ablative systems insulate atmospheric reentry vehicles from reentry plasmas generated by atmospheric braking from orbital and exo-orbital velocities. Due to the necessity that these materials create a temperature gradient up to several thousand Kelvin over their thickness, it is important that these materials are near their pristine state prior to reentry. These materials may also be on exposed surfaces to space environment threats like orbital debris and meteoroids leaving a probability that these exposed surfaces will be below their prescribed values. Owing to the typical small size of impact craters in these materials, the local flow fields over these craters and the ablative process afford some margin in thermal protection designs for these locally reduced performance values. In this work, tests to develop ballistic performance models for thermal protection materials typical of those being used on Orion are discussed. A density profile as a function of depth of a typical monolithic ablator and substructure system is shown in Figure 1a.

Miller, J. E.↗
NASA NTRS1984

Application of holography to flow visualization

Laser holographic interferometry is being applied to many different types of aerodynamics problems. These include two and three dimensional flows in wind tunnels, ballistic ranges, rotor test chambers and turbine facilities. Density over a large field is measured and velocity, pressure, and mach number can be deduced.

Lee, G.↗
NASA NTRS1985

Ablation of Galileo Probe heat-shield models in a ballistic range

Several 1/24-scale models of the Galileo Probe made of carbon-phenolic materials were flown in a ballistic range to test their ablation characteristics. Mostly radiative or all-convective heating environments were produced by using argon or air as the test gas, respectively, to simulate the Jovian entry heating environments. The experimental results were compared with the theoretical predictions made using the computer codes of radiating shock layer environment (RASLE) and charring materials ablation (CMA). The experimental data obtained in argon agreed approximately with the theoretical predictions. The data for air agreed approximately with the theory when turbulence and surface roughness effects were accounted for. The data imply that the Galileo Probe heat shield was adequately designed.

Park, C.↗
NASA NTRS2003

Durability Assessment of Various Gamma TiAl Alloys

Seven cast and one wrought gamma-alloys were ballistically impacted and tested under high cycle fatigue. The fatigue strength of each alloy was characterized as a function of initial flaw size and modeled using a threshold-based fracture mechanics approach.

Lerch, Brad↗
NASA NTRS2010

Contingency Operations of Americas Next Moon Rocket, Ares V

America has begun the development of a new space vehicle system which will enable humans to return to the moon and reach even farther destinations. The system is called Constellation: it has 2 earth-launch vehicles, Ares I and Ares V; a crew module, Orion; and a lander, Altair with descent and ascent stages. Ares V will launch an Earth Departure Stage (EDS) and Altair into low earth orbit. Ares I will launch the Orion crew module into low earth orbit where it will rendezvous and dock with the Altair and EDS "stack". After rendezvous, the stack will contain four complete rocket systems, each capable of independent operations. Of course this multiplicity of vehicles provides a multiplicity of opportunities for off-nominal behavior and multiple mitigation options for each. Contingency operations are complicated by the issues of crew safety and the possibility of debris from the very large components impacting the ground. This paper examines contingency operations of the EDS in low earth orbit, during the boost to translunar orbit, and after the translunar boost. Contingency operations under these conditions have not been a consideration since the Apollo era and analysis of the possible contingencies and mitigations will take some time to evolve. Since the vehicle has not been designed, much less built, it is not possible to evaluate contingencies from a root-cause basis or from a probability basis; rather they are discussed at an effects level (such as the reaction control system is consuming propellant at a high rate). Mitigations for the contingencies are based on the severity of the off-nominal condition, the time of occurrence, recovery options, options for alternate missions, crew safety, evaluation of the condition (forensics) and future prevention. Some proposed mitigations reflect innovation in thinking and make use of the multiplicity of on-orbit resources including the crew; example: Orion could do a "fly around" to allow the crew to determine the condition and cause of a partially separated payload shroud. Other mitigations are really alternate missions; example, an engine out on during ascent resulted in insufficient propellant for the lunar mission, but the on-orbit vehicle stack is otherwise perfect and can pursue an alternate mission, such as a high ballistic trajectory to test the high-speed atmospheric reentry of Orion. Evaluation and presentation of contingency operations at this early stage of the development of the Ares V rocket will improve the design of the vehicle and lay the groundwork for the exhaustive contingency planning which must be done after the vehicle is built as preparations for operations.

Jaap, John↗
NASA NTRS2013

Automating Initial Guess Generation for High Fidelity Trajectory Optimization Tools

Many academic studies in spaceflight dynamics rely on simplified dynamical models, such as restricted three-body models or averaged forms of the equations of motion of an orbiter. In practice, the end result of these preliminary orbit studies needs to be transformed into more realistic models, in particular to generate good initial guesses for high-fidelity trajectory optimization tools like Mystic. This paper reviews and extends some of the approaches used in the literature to perform such a task, and explores the inherent trade-offs of such a transformation with a view toward automating it for the case of ballistic arcs. Sample test cases in the libration point regimes and small body orbiter transfers are presented.

design process↗
NASA NTRS1987

On the simulation of ballistic shock loads

Blast or penetrator-impact induced shocks are characterized by high acceleration levels, particularily in the higher frequency range and for a short time duration. These shocks are dangerous for the equipment of ships, combat vehicles, airplanes or spacecraft structures. As ballistic shock loads are insufficiently simulated by laboratory test machines, researchers designed a ballistic shock simulator. The impact induced shocks are simulated by an explosive and the vehicle to be bombarded is replaced by a simplified structure. This structure is suitable to accommodate any equipment which can be tested up to their load limits.

Hollburg, Uwe↗
NASA NTRS2011

Capabilities of the Impact Testing Facility at Marshall Space Flight Center

The test and analysis capabilities of the Impact Testing Facility at NASA's Marshall Space Flight Center are described. Nine different gun systems accommodate a wide range of projectile and target sizes and shapes at velocities from subsonic through hypersonic, to accomplish a broad range of ballistic and hypervelocity impact tests. These gun systems include ballistic and microballistic gas and powder guns, a two-stage light gas gun, and specialty guns for weather encounter studies. The ITF "rain gun" is the only hydrometeor impact gun known to be in existence in the United States that can provide single impact performance data with known raindrop sizes. Simulation of high velocity impact is available using the Smooth Particle Hydrodynamic Code. The Impact Testing Facility provides testing, custom test configuration design and fabrication, and analytical services for NASA, the Department of Defense, academic institutions, international space agencies, and private industry in a secure facility located at Marshall Space Flight Center, on the US Army's Redstone Arsenal in Huntsville, Alabama. This facility performs tests that are subject to International Traffic in Arms Regulations (ITAR) and DoD secret classified restrictions as well as proprietary and unrestricted tests for civil space agencies, academic institutions, and commercial aerospace and defense companies and their suppliers.

Finchum, Andy↗
NASA NTRS1958

Heat-Transfer and Pressure Measurements from a Flight Test of the Third 1/18-Scale Model of the Titan Intercontinental Ballistic Missile up to a Mach Number of 3.86 and Reynolds Number per Foot of 23.5 x 10(exp 6) and a Comparison with Heat Transfer

Heat-transfer and pressure measurements were obtained from a flight test of a 1/18-scale model of the Titan intercontinental ballistic missile up to a Mach number of 3.86 and Reynolds number per foot of 23.5 x 10(exp 6) and are compared with the data of two previously tested 1/18-scale models. Boundary-layer transition was observed on the nose of the model. Van Driest's theory predicted heat-transfer coefficients reasonably well for the fully laminar flow but predictions made by Van Driest's theory for turbulent flow were considerably higher than the measurements when the skin was being heated. Comparison with the flight test of two similar models shows fair repeatability of the measurements for fully laminar or turbulent flow.

Graham, John B., Jr.↗