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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Design and control of a hand exoskeleton for use in extravehicular activities

To counter problems inherent in extravehicular activities (EVA) and complex space operations, an exoskeleton, a unique adaptive structure, has been designed. The exoskeleton fits on the hand and powers the proximal and middle phalanges of the index finger, the middle finger, and the combined ring and little finger. A kinematic analysis of the exoskeleton joints was performed using the loop-closure method. This analysis determined the angular displacement and velocity relationships of the exoskeleton joints. This information was used to determine the output power of the exoskeleton. Three small DC motors (one for each finger) are used to power the exoskeleton. The motors are mounted on the forearm. Power is transferred to the exoskeleton using lead screws. The control system for the exoskeleton measures the contact force between the operator and the exoskeleton. This information is used as the input to drive the actuation system. The control system allows the motor to rotate in both directions so that the operator may close or open the exoskeleton.

Shields, B.↗
NASA NTRS2018

Optimization of a Multifunctional Hot Structure Aeroshell for Mars Entry

Vehicle size and weight are driving cost factors in sending vehicles into space because the cost of launch is directly related to the payload mass being delivered. Vehicle size and weight have a larger impact on deep- space missions compared to sending a payload to low Earth orbit due to the extra fuel and supplies required to complete the longer duration mission. One area of study for possible vehicle volume or weight reduction is the thermal protection system (TPS) of a vehicle. Hot structures have been proposed as a TPS concept which can carry both primary structural loads and thermal loads. The use of hot structures on a Mars entry vehicle may be feasible and have potential volume and weight savings over the current state of the art ablative TPS technology. A preliminary trade study was performed on a mid lift-to-drag aeroshell Mars entry concept vehicle; comparing the weight and skin thickness of a vehicle using ablative TPS with a vehicle using hot structures. Independent thermal and structural analyses were performed to determine the minimum mass designs. The goal of this study was to determine if the use of hot structures was feasible and had potential for significant vehicle volume and weight savings over the current state of the art. This trade study found that use of a hot structures leads to a feasible alternative to ablative TPS technology, with potential 53% weight and 22% thickness (volume) saving benefits that could enable future missions.

Langston, Sarah L.↗
NASA NTRS2005

Human Factors in Space Flight

After forty years of experience with human space flight (Table 1), the current emphasis is on the design of space vehicles, habitats, and missions to ensure mission success. What lessons have we learned that will affect the design of spacecraft for future space exploration, leading up to exploring Mars? This chapter addresses this issue in four sections: Anthropometry and Biomechanics; Environmental Factors; Habitability and Architecture; and Crew Personal Sustenance. This introductory section introduces factors unique to space flight. A unique consideration for design of a habitable volume in a space vehicle is the lack of gravity during a space flight, referred to as microgravity. This affects all aspects of life, and drives special features in the habitat, equipment, tools, and procedures. The difference in gravity during a space mission requires designing for posture and motion differences. In Earth s gravity, or even with partial gravity, orientation is not a variable because the direction in which gravity acts defines up and down. In a microgravity environment the working position is arbitrary; there is no gravity cue. Orientation is defined primarily through visual cues. The orientation within a particular crew station or work area is referred to as local vertical, and should be consistent within a module to increase crew productivity. Equipment was intentionally arranged in various orientations in one module on Skylab to assess the efficiency in use of space versus the effects of inconsistent layout. The effects of that arrangement were confusion on entering the module, time spent in re-orientation, and conflicts in crew space requirements when multiple crew members were in the module. Design of a space vehicle is constrained by the three major mission drivers: mass, volume and power. Each of these factors drives the cost of a mission. Mass and volume determine the size of the launch vehicle directly; they can limit consumables such as air, water, and propellant; and they impact crew size and the types of activities the crew performs. Power is a limiting factor for a space vehicle. All environmental features (e.g., atmosphere, temperature, lighting) require power to maintain them. Power can be generated from batteries, from fuel cells, or from solar panels. Each of these sources requires lifting mass and volume from Earth, driving mission cost. All engineering decisions directly impact the design for habitation design and usage. For instance, if fuel cells are used they produce water, which is used for drinking and food preparation. If a different power source is used water has to be carried and stored on the vehicle which then directly impacts the food system choice as well as the launch weight of the vehicle.

Woolford, Barbara J.↗
NASA NTRS2019

Gateway Modeling and Simulation Plan

This plan institutes direction across the Gateway Program and the Element Projects to ensure that Cross Program M&S are produced in a manner that (1) generate the artifacts required for NASA-STD-7009 compliance, (2) ensures interoperability of M&S exchanged and integrated across the program and, (3) drives integrated development efforts to provide cross-domain integrated simulation of the Gateway elements, space environment, and operational scenarios. This direction is flowed down via contractual enforcement to prime contractors and includes both the GMS requirements specified in this plan and the NASASTD- 7009 derived requirements necessary for compliance. Grounding principles for management of Gateway Models and Simulations (M&S) are derived from the Columbia Accident Investigation Board (CAIB) report and the Diaz team report, “A Renewed Commitment to Excellence.” As an outcome of these reports, and in response to Action 4 of the Diaz team report, the NASA Standard for Models and Simulations, NASA-STD-7009 was developed. The standard establishes M&S requirements for development and use activities to ensure proper capture and communication of M&S pedigree and credibility information to Gateway program decision makers. Through the course of the Gateway program life cycle M&S will be heavily relied upon to conduct analysis, test products, support operations activities, enable informed decision making and ultimately to certify the Gateway with an acceptable level of risk to crew and mission. To reduce risk associated with M&S influenced decisions, this plan applies the NASA-STD-7009 requirements to produce the artifacts that support credibility assessments and ensure the information is communicated to program management.

NASA-STD-7009↗
NASA NTRS2020

Recent Developments in Tolerancing Methods for Imaging Spectrometers

We discuss detailed tolerancing methods developed for imaging spectrometers at NASA Jet Propulsion Laboratory, California Institute of Technology using the Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer as an illustrative example. We tolerance five metrics simultaneously: along-track response function, cross-track response function, spectral response function, spectral centroid uniformity, and spatial centroid uniformity. A method to calculate tolerancing sensitivities for each metric directly, a method to statistically combine Monte Carlo files from multiple tolerancing runs, and an example summary error budgets that communicate the key and driving tolerances for each metric are discussed. These methods facilitate rapid and semi-automated assessment of the predicted performance of imaging spectrometer systems from design through to assembly and launch life cycle, using metrics that are directly relevant to the extraction of accurate spectroscopic data from these instruments.

Mouroulis, Pantazis↗
NASA NTRS1980

The polarization and directivity of solar-flare hard X-ray bremsstrahlung from a thermal source

The polarization and directivity of hard X-ray bremsstrahlung from a thermal source consisting of a region in which a thermal flux drives a pair of steel collisionless conduction fronts were evaluated. The conduction fronts are symmetrically driven from a central region, heated by the flare energy dissipation process. By comparing results with similar calculations based on a nonthermal thick-target electron beam model of the source, it was aimed to determine the degree to which the observed polarization and directivity of solar flare hard X-rays favor either model. Results which exhibit significant polarization and directivity of the hard X-ray radiation emitted by the source are produced by using Maxwellian electron-phase-space distribution functions modified to take into account a directional heat flux and a steady direct current in the X-ray source, and a fully relativistic treatment of the bremsstrahlung emission process. The results are consistent with solar hard X-ray anisotropy and polarization observations to date, although these observations are too crude to be conclusive.

Emslie, A. G.↗
NASA NTRS1994

The FC-1D: The profitable alternative Flying Circus Commercial Aviation Group

The FC-1D was designed as an advanced solution for a low cost commercial transport meeting or exceeding all of the 1993/1994 AIAA/Lockheed request for proposal requirements. The driving philosophy behind the design of the FC-1D was the reduction of airline direct operating costs. Every effort was made during the design process to have the customer in mind. The Flying Circus Commercial Aviation Group targeted reductions in drag, fuel consumption, manufacturing costs, and maintenance costs. Flying Circus emphasized cost reduction throughout the entire design program. Drag reduction was achieved by implementation of the aft nacelle wing configuration to reduce cruise drag and increase cruise speeds. To reduce induced drag, rather than increasing the wing span of the FC-1D, spiroids were included in the efficient wing design. Profile and friction drag are reduced by using riblets in place of paint around the fuselage and empennage of the FC-1D. Choosing a single aisle configuration enabled the Flying Circus to optimize the fuselage diameter. Thus, reducing fuselage drag while gaining high structural efficiency. To further reduce fuel consumption a weight reduction program was conducted through the use of composite materials. An additional quality of the FC-1D is its design for low cost manufacturing and assembly. As a result of this design attribute, the FC-1D will have fewer parts which reduces weight as well as maintenance and assembly costs. The FC-1D is affordable and effective, the apex of commercial transport design.

Meza, Victor J.↗
NASA NTRS2000

Exploiting the Temperature Dependence of Magnetic Susceptibility to Control Convection in Fundamental Studies of Solidification Phenomena

It is well known that convection is a dominant mass transport mechanism when materials are solidified on Earth's surface. This convection is caused by gradients in density (and therefore gravitational force) that are brought about by gradients in temperature, composition or both. Diffusion of solute is therefore dwarfed by convection and the study of fundamental parameters, such as dendrite tip shape and growth velocity in the absence of convection is nearly impossible. Significant experimental work has therefore been carried out in orbiting laboratories with the intent of minimizing convection by minimizing gravity. One of the best known experiments of this kind is the Isothermal Dendritic Growth Experiment (IDGE), supported by NASA. Naturally such experiments are costly and one objective of the present investigation is to develop an experimental method whereby convection can be- halted, in solidification and other experiments, on the surface. A second objective is to use the method to minimize convection resulting from the residual accelerations suffered by experiments in microgravity. The method to be used to minimize convection relies on the dependence of the magnetic susceptibility of a fluid on temperature or composition (whichever is driving convection). All materials experience a force when placed in a magnetic field gradient. The direction and magnitude of that force depend on the magnetic susceptibility of the material. Consequently the force will vary if the susceptibility varies with temperature or composition. With a magnetic field gradient in the right direction (typically upward) and of the right magnitude, this variation in the magnetic force can be made to exactly cancel the variation in the gravitational force. Expressed another way, normal buoyancy is exactly countered by a "magnetic buoyancy". To demonstrate the principle, a solution of MnC12 in water has been used. First the variation of the susceptibility of this paramagnetic solution with temperature and concentration was measured. Then a "cell", containing this solution and 50mm long by 15mm high by 155mm wide, was placed in a superconducting magnet at Marshall Space Flight Center. The magnetic field was measured at various positions within the bore of the magnet using a Hall effect probe. In this way, a position was found where the magnetic field gradient was predominantly upward; the magnitude of the gradient could then be adjusted by adjusting the current of the magnet. The ends of the cell consisted of machined copper blocks maintained at controlled temperatures by circulating water from constant temperature baths. The walls of the cell were of rectangular section glass tubing so that the cell contents could be seen. Velocities arising from thermal gradients within the cell were measured by particle image velocimetry (PIV). Particles used for this purpose were silver-coated hollow glass spheres of micrometers diameter and nearly the same density as the solution. A central vertical plane of the cell was illuminated by a laser beam passing through a cylindrical lens. Digital images of the particles were captured on a CCD camera and fed to a computer so that frame-to-frame movements of particles traveling with the fluid were captured. These images were employed to compute velocity maps using commercial PIV software. In a typical experiment the cold end of the cell was maintained at 10C and the warm end at 30 C. With no current in the magnet, i.e.- with natural -convection allowed to occur, the fluid was observed to circulate with an average speed of approximately 0.3 millimeters per second. It was visually apparent that this circulation was diminished as the current was increased. At currents of approximately 20A the flow was halted, to within the precision of the PIV measurements. At yet higher currents the convection was reversed with the hotter solution sinking and the cooler solution rising. At 40A this reversed convection had speeds averaging 0.43 millimeters per second. The measurements of susceptibility and density allow an estimate of the field gradient necessary to halt convection in the experiment. That estimate was 7.8T (squared) per meter and the convection was observed to halt in the magnet at a current giving 7.21T (squared) per meter from the magnetic field measurements. Calculations of the flow have been carried out using the computational fluid dynamics software FLUENT and show good agreement with the measurements.

Seybert, C. D.↗
NASA NTRS2001

Wave Augmented Diffuser for Centrifugal Compressor

A wave augmented diffuser for a centrifugal compressor surrounds the outlet of an impeller that rotates on a drive shaft having an axis of rotation. The impeller brings flow in in an axial direction and imparts kinetic energy to the flow discharging it in radial and tangential directions. The flow is discharged into a plurality of circumferentially disposed wave chambers. The wave chambers are periodically opened and closed by a rotary valve such that the flow through the diffuser is unsteady. The valve includes a plurality of valve openings that are periodically brought into and out of fluid communication with the wave chambers. When the wave chambers are closed, a reflected compression wave moves upstream towards the diffuser bringing the flow into the wave chamber to rest. This action recovers the kinetic energy from the flow and limits any boundary layer growth. The flow is then discharged in an axial direction through an opening in the valve plate when the valve plate is rotated to an open position. The diffuser thus efficiently raises the static pressure of the fluid and discharges an axially directed flow at a radius that is predominantly below the maximum radius of the diffuser.

Skoch, Gary J.↗
NASA NTRS2007

Anti-radiation vaccine: Immunologically-based Prophylaxis of Acute Toxic Radiation Syndromes Associated with Long-term Space Flight

Protecting crew from ionizing radiation is a key life sciences problem for long-duration space missions. The three major sources/types of radiation are found in space: galactic cosmic rays, trapped Van Allen belt radiation, and solar particle events. All present varying degrees of hazard to crews; however, exposure to high doses of any of these types of radiation ultimately induce both acute and long-term biological effects. High doses of space radiation can lead to the development of toxicity associated with the acute radiation syndrome (ARS) which could have significant mission impact, and even render the crew incapable of performing flight duties. The creation of efficient radiation protection technologies is considered an important target in space radiobiology, immunology, biochemistry and pharmacology. Two major mechanisms of cellular, organelle, and molecular destruction as a result of radiation exposure have been identified: 1) damage induced directly by incident radiation on the macromolecules they encounter and 2) radiolysis of water and generation of secondary free radicals and reactive oxygen species (ROS), which induce chemical bond breakage, molecular substitutions, and damage to biological molecules and membranes. Free-radical scavengers and antioxidants, which neutralize the damaging activities of ROS, are effective in reducing the impact of small to moderate doses of radiation. In the case of high doses of radiation, antioxidants alone may be inadequate as a radioprotective therapy. However, it remains a valuable component of a more holistic strategy of prophylaxis and therapy. High doses of radiation directly damage biological molecules and modify chemical bond, resulting in the main pathological processes that drive the development of acute radiation syndromes (ARS). Which of two types of radiation-induced cellular lethality that ultimately develops, apoptosis or necrosis, depends on the spectrum of incident radiation, dose, dose rate, and functional conditions of impacted cells/organisms. The administration of an experimental anti-radiation vaccine may provide an immunologically based, adjunct method of prevention or prophylaxis against clinical ARS. The administration of experimental anti-radiation serum (ARS) and the use of the blood dialysis methods, such as immune plasma-sorption, may assist in the clearance of radiation-specific toxins and may enhance established strategies for the mitigation of the biological effects leading to ARS, and should be evaluated for use on exploration-class space missions.

Popov, Dmitri↗
NASA NTRS2016

Systems Analysis of In-Space Manufacturing Applications for the International Space Station and the Evolvable Mars Campaign

Maintenance logistics support is a significant challenge for extended human operations in space, especially for missions beyond Low Earth Orbit (LEO). For missions to Mars (such as NASA's Evolvable Mars Campaign (EMC)), where timely resupply or abort in the event of emergency will not be possible, maintenance logistics mass is directly linked to the Probability of Loss of Crew (P(LoC)), and the cost of driving down risk is an exponential increase in mass requirements. The logistics support strategies that have maintained human operations in LEO will not be effective for these deep space missions. In-Space Manufacturing (ISM) is a promising technological solution that could reduce logistics requirements, mitigate risks, and augment operational capabilities, enabling Earth- independent human spaceflight. This paper reviews maintenance logistics challenges for spaceflight operations in LEO and beyond, and presents a summary of selected results from a systems analysis of potential ISM applications for the ISS and EMC. A quantitative modeling framework and sample assessment of maintenance logistics and risk reduction potential of this new technology is also presented and discussed.

Owens, Andrew C.↗
NASA NTRSDate not supplied

Real-Time Science Decisioning During High Tempo-High Intensity Mission Operations and the Role of Analogs

Introduction: NASA’s VIPER mission presents a unique operational paradigm within the history of robotic spaceflight. The proximity of the Moon to the Earth and the terrain elements (surface characteristics, light/shadow dynamics, communication links) of the lunar South Polar landing site create unprecedented operational conditions between these two planetary bodies. Apollo era lunar science and exploration included humans in situ to operate instruments and assimilate observational inputs in real-time. Previous lunar orbital missions have worked to operational timescales, e.g., decisional timelines and communication exchanges, that were weeks in length. Mars rover missions have worked to operational timescales, e.g., decisional timelines and communication exchanges between Mars and Earth, that were hours, days, and weeks in length. In the case of the VIPER mission, our operational decisioning for rover driving and instrument commanding will be compressed to minute-scale timeframes. These operational conditions directly impact the manner and speed with which the VIPER Science Team (VST) is required to synthesize and analyze data and produce timely science-driven decisions throughout surface mission operations. The VST shall provide mission enhancing scientific input to guide rover traverse planning and drill site confirmation and selection throughout surface operations. Further, the VST input will be of vital importance to the mission’s ability to maximize science return and to meet broader NASA objectives for future lunar in-situ resource utilization (ISRU)and exploration activities. The VST co-located in the Mission Science Center (MSC) will be responsive to the tactical operational cadence of the Mission Operations Center (MOC) and will provide further strategic and Long-Term Planning (LTP) guidance to the mission. The VIPER Science Operations & Integration(SO&I)team has developed an architecture that is focused on the infusion of science-decisioning into the operational framework and execution cadence of VIPER. NASA analog research has played a significant role in the construction of the VIPER science operations systems. As an example, the SO&I team has led analog missions that have focused on bringing together expertise in the sciences (natural, applied and social) and in operations in service of learning how to build and hold together interdisciplinary work environments and what tools are needed to support high tempo, high intensity integrated decisioning. These experiences have provided an essential foundation of knowledge to the VIPER team. Those analogs that specifically influenced the VIPER science operations construct were identified through a process of comparative analysis to prioritize those that offered relevance in whole or in part, and those that did not. The analog research output that provided extensibility to the VIPER science operations architecture included remote teams of humans and robots in cooperation (synchronous and asynchronous) with simulated earthbound systems, engineering and science teams, and the integrated assembly of tools that supported scientific analysis and data synthesis and provided infrastructure for the remote testing framework. Analogs which included real-time data monitoring, synthesis, visualization and access in a democratized and operationalized manner were of particular interest to the development of the VIPER MSC toolset both in terms of the technology and the processes used to develop the supporting infrastructure. We anticipate that each subsequent mission to the lunar south pole, whether with robots or humans, will be able to optimize science and exploration return by evolving strategies to infuse real-time collaborative science-decisioning. Furthermore, these efforts will result in a foundation for science operations development in support of human-robotic exploration of deep space and Mars. NASA analogs can continue to provide the opportunity to prepare, test and iterate on the operational concepts and tools that will support these ever-expanding space exploration efforts. Our presentation will include an overview of the VIPER Science Operations & Integration development process and specifics on what aspects of analog research have had a significant impact on our work systems.

D S S Lim↗
NASA NTRS1993

Simulation motion effect on single axis compensatory tracking

An experiment that examined how changes in a motion platform drive filter affect pilot-vehicle performance and opinion was conducted on the NASA Ames Vertical Motion Simulator. Pilots controlled a simplified helicopter model in the vertical or the directional axis and tracked a randomly moving target aircraft in the presence of a random disturbance. With both tasks, variations from full motion to fixed-base conditions were made in the high-pass drive filter gain and natural frequency. The results indicate that vertical motion did not affect the open-loop pilot-vehicle target-tracking crossover frequency, but target-tracking phase margins improved with increased filter gain or decreased natural frequency. Vertical disturbance-rejection crossover frequency increased with decreasing filter natural frequency, while disturbance rejection phase margins improved with increasing filter gain. Vertical tracking errors increased significantly when all vertical motion was removed. No significant differences were measured among the directional configurations, which indicates that pure yaw motion cues may not be as important as previously thought in flight simulation.

Schroeder, Jeffery A.↗
NASA NTRS2022

Co-leveraging Scientific Advances in Space Biology and Astrobiology Towards Achieving NASA’s Life Science Objectives

Executive Summary: Distinct lines of scientific inquiry drives the separation of NASA’s fundamental life science research into Space Biology and Astrobiology. This division developed as a way to place life scientists alongside experts in the physical constraints that define the acclimation, adaptation and evolution of biology systems relevant to their respective subjects. For astrobiology, integration with disciplines such as geology, geochemistry, astronomy, planetary science, etc., enables a comprehensive assessment of the physical environment and its co-evolution with biological processes. Space Biology’s co-location with Physical Sciences places life science researchers adjacent to experts in the physical phenomena associated with microgravity and spaceflight, enabling an understanding of how the spaceflight environment affects biological systems. Despite this separation, aspects of both disciplines have converged on a similar, fundamental objective: to describe and understand the dynamics of complex living communities in the contexts of their physical environments. While the environmental systems and timescales are dramatically different, continuing to motivate the separation into distinct fields, similarities in the underlying objective present opportunities to find efficiencies, reduce overlap, and minimize duplication of effort. Space Biology and Astrobiology share a common need to understand microbial physiology in extreme environments – whether the ‘built’ spaceflight environment or the natural environments in which many astrobiology studies are conducted. In particular, open questions in each discipline require the development of quantitative frameworks, applicable at the ecosystem level, that support predictive capabilities for environments where observations are sparse. Additionally, both disciplines have a need to prepare, detect, and analyze the (potential) biological signal in complex samples-often in a completely autonomous fashion. The next decade will see NASA Space Biology moving to understand and describe the effects of the beyond low-earth orbit (BLEO) spaceflight environment on living systems. This new direction will dramatically reduce the opportunities for ground-based analysis of space-flown samples, driving space biology investigations towards fully autonomous experiments and missions. At the same time, astrobiology life detection missions aimed at detecting biosignatures on Mars and icy moons in the outer solar system could benefit from fully automated sample processing and analysis. There are opportunities to leverage instrument and method development between both disciplines within the context of these BLEO missions.

Astrobiology↗
NASA NTRS1973

Neutral winds above 200 km at high latitudes.

Electrically neutral, luminous clouds are a by-product of chemical releases conducted to create barium ion clouds for the measurement of electric fields. Wind measurements provided by the motions of these clouds are particularly valuable in that the motions can be directly compared with convective ion drift motions to test the importance of ion drag forces. Motion from multiple releases between 200 and 300 km from 15 rockets launched from four high-latitude locations is analyzed in this paper. The observations in the evening and midnight hours at magnetic latitudes above 65 deg strongly suggest that in these regions ion drag is the dominant force in driving neutral winds between 200 and 300 km. In the morning sector, it is evident that neutral wind observations cannot be directly interpreted in terms of ion drag; other factors must be considered.

Meriwether, J. W.↗
NASA NTRS1981

Equatorial superrotation in a thermally driven zonally symmetric circulation

Near the equator where the Coriolis force vanishes, the momentum balance for the axially symmetric circulation is established between horizontal and vertical diffusion, which, a priori, does not impose constraints on the direction or magnitude of the zonal winds. Solar radiation absorbed at low latitudes is a major force in driving large scale motions with air rising near the equator and falling at higher latitudes. In the upper leg of the meridional cell, angular momentum is redistributed so that the atmosphere tends to subrotate (or corotate) at low latitudes and superrotate at high latitudes. In the lower leg, however, the process is reversed and produces a tendency for the equatorial region to superrotate. The outcome depends on the energy budget which is closely coupled to the momentum budget through the thermal wind equation; a pressure (temperature) maximum is required to sustain equatorial superrotation. Such a condition arises in regions which are convectively unstable and the temperature lapse rate is superadiabatic. It should arise in the tropospheres of Jupiter and Saturn; planetary energy from the interior is carried to higher altitudes where radiation to space becomes important. Upward equatorial motions in the direct and indirect circulations (Ferrel-Thomson type) imposed by insolation can then trap dynamic energy for equatorial heating which can sustain the superrotation of the equatorial region.

Mayr, H. G.↗
NASA NTRS1974

Flaw detection by mechanical resonant measurement

Testing technique is based on analysis of varying frequency scan applied to measured samples. Any changes in resonant-frequency harmonics detected in samples are used to indicate size of fault. Testing apparatus uses drive mechanism to apply vibrating force to sample. Force is applied longitudinally along axis to eliminate directionality on flexural vibrations.

Buck, O.↗