FM/AM telemetry to measure impact accelerations
Impact acceleration measured by accelerometers and FM/AM telemetry
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Impact acceleration measured by accelerometers and FM/AM telemetry
Usaf impact acceleration and facilities - aero- space vehicle, biodynamics, human tolerance
The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.
The U.S. Research Impact Alliance (USRIA) was created with a vision to leverage successful models that accelerate technology development and commercialization, and support startup businesses based upon federal research investments. Building upon lessons learned and feedback from cohort teams, the USRIA programs have morphed into customized solutions that offer services which provide the most impact to startup businesses. Based upon discussions with small and startup businesses, entrepreneurs, and technology developers, a variety of resources have been developed to support each of these target audiences. USRIA created program differentiators to offer one-on-one engagement and direct communication with cohort teams, highly relevant conversations with targeted introductions, and minimal “class” time (only used when an issue is applicable to all cohort members).
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FM/AM telemetry circuits with three axis piezoelectric accelerometer for measurements during impact tests of soft landing models
A steady state dynamic response model for the radial motion of the aorta is developed from in vivo pressure-displacement and nerve stimulation experiments on canines. The model represented by a modified Van der Pol wave motion oscillator closely predicts steady state and perturbed response results. The applicability of the steady state canine aortic model to tailward acting impact forces is studied by means of the perturbed phase plane of the oscillator. The backflow through the aortic arch resulting from a specified acceleration-time profile is computed and an analysis for predicting the forced motion aortic response is presented.
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Telemetry package uses three separate FM/AM transmitters, one for each axis of measurement. Three AM receivers and a tape recorder are used for receiving, demodulating, and recording the acceleration signal.
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One of the goals of the NASA Occupant Protection Group is to understand the human tolerance to dynamic loading. This knowledge has to come through indirect approaches such as existing human response databases, anthropometric test devices (ATD), animal testing, post‐mortem human subjects, and models. This study investigated the biofidelity of the National Highway Traffic Safety Administration's ATD named the THOR (test device for human occupant restraint). If THOR responds comparably to humans, then it could potentially be used as a human surrogate to help validate space vehicle requirements for occupant protection. The THOR responses to frontal and spinal impacts (ranging from 8 to 12 G with rise times of 40, 70, and 100 ms) were measured and compared to human volunteer responses (95 trials in frontal and 58 in spinal) previously collected by the U. S. Air Force on the same horizontal impact accelerator. The impact acceleration profiles tested are within the expected range of multi‐purpose crew vehicle (MPCV) landing dynamics. A correlation score was calculated for each THOR to human comparison using CORA (CORrelation and Analysis) software. A two‐parameter beta distribution model fit was obtained for each dependent variable using maximum likelihood estimation. For frontal impacts, the THOR head x‐acceleration peak response correlated with the human response at 8 and 10‐G 100 ms but not 10‐G 70 ms. The phase lagged the human response. Head z‐acceleration was not correlated. Chest x‐acceleration was in phase, had a higher peak response, and was well correlated with lighter subjects (Cora = 0.8 for 46 kg vs. Cora = 0.4 for 126 kg). Head x‐displacement had a leading phase. Several subjects responded with the same peak displacement but the mean of the group was lower. The shoulder x‐displacement was in phase but had higher peaks than the human response. For spinal impacts, the THOR head x‐acceleration was not well correlated. Head and chest z‐acceleration was in phase but had a higher peak response. Chest z‐acceleration was highly correlated with heavier subjects at lower G pulses (Cora = 0.86 for 125 kg at 8 G). The human response was variable in shoulder z‐displacement but the THOR was in phase and was comparable to the mean peak response. Head xand z‐displacement was in phase but had higher peaks. Seat pan forces were well correlated, were in phase, but had a larger peak response than most subjects. The THOR does not respond to frontal and spinal impacts exactly the same way that a human does. Some responses are well matched and others are not. Understanding the strengths and weaknesses of this ATD is an important first step in determining its usefulness in occupant protection at NASA
One of the goals of the NASA Occupant Protection Group is to understand the human tolerance to dynamic loading. This knowledge has to come through indirect approaches such as existing human response databases, anthropometric test devices (ATD), animal testing, post-‐mortem human subjects, and models. This study investigated the biofidelity of the National Highway Traffic Safety Administration's ATD named the THOR (test device for human occupant restraint). If THOR responds comparably to humans, then it could potentially be used as a human surrogate to help validate space vehicle requirements for occupant protection. The THOR responses to frontal and spinal impacts (ranging from 8 to 12 G with rise times of 40, 70, and 100 ms) were measured and compared to human volunteer responses (95 trials in frontal and 58 in spinal) previously collected by the U. S. Air Force on the same horizontal impact accelerator. The impact acceleration profiles tested are within the expected range of multi-‐purpose crew vehicle (MPCV) landing dynamics. A correlation score was calculated for each THOR to human comparison using CORA (CORrelation and Analysis) software. A two-‐parameter beta distribution model fit was obtained for each dependent variable using maximum likelihood estimation. For frontal impacts, the THOR head x-‐acceleration peak response correlated with the human response at 8 and 10-‐G 100 ms but not 10-‐G 70 ms. The phase lagged the human response. Head z-‐acceleration was not correlated. Chest x-‐acceleration was in phase, had a higher peak response, and was well correlated with lighter subjects (Cora = 0.8 for 46 kg vs. Cora = 0.4 for 126 kg). Head x-‐displacement had a leading phase. Several subjects responded with the same peak displacement but the mean of the group was lower. The shoulder x-‐displacement was in phase but had higher peaks than the human response. For spinal impacts, the THOR head x-‐acceleration was not well correlated. Head and chest z-‐acceleration was in phase but had a higher peak response. Chest z-‐acceleration was highly correlated with heavier subjects at lower G pulses (Cora = 0.86 for 125 kg at 8 G). The human response was variable in shoulder z-‐displacement but the THOR was in phase and was comparable to the mean peak response. Head x-‐ and z-‐displacement was in phase but had higher peaks. Seat pan forces were well correlated, were in phase, but had a larger peak response than most subjects. The THOR does not respond to frontal and spinal impacts exactly the same way that a human does. Some responses are well matched and others are not. Understanding the strengths and weaknesses of this ATD is an important first step in determining its usefulness in occupant protection at NASA
Method for estimating impact accelerations of shipping containers mounted on railroad car
A plastic holder, which retains a crystal blank with standard silvered contacts sandwiched between two copper contacts, protects the crystal against vibration during high acceleration and impact.
In order to reduce the cost of landing small payloads on Mars, a new technology is being developed: the Small High Impact Energy Landing Device concept (SHIELD). The purpose of SHIELD is to provide a low-cost option to deliver up to 6 kg of science payload to the surface of Mars. SHIELD could be launched as a hosted payload, rideshare on an EELV secondary payload adapter (ESPA), or launching from a dedicated small launch vehicle using a kick stage. The SHIELD concept can achieve low-cost access to Mars by taking advantage of a low ballistic coefficient design to decelerate safely instead of using the typically required parachutes and/or propulsion to decelerate and stabilize itself during entry, decent, and landing (EDL). Current finite element simulations suggest that SHIELD would experience an impact acceleration pulse ranging from 1000 to 2000 g’s with a duration of 8 milliseconds. The SHIELD concept payload subsystem includes a “ruggedized” small warm electronics box (WEB). The WEB houses the telecommunications, command and data handling, thermal control, electrical power, and payload subsystems while maintaining an internal operating temperature ranging between -20° to 20° C. The system is designed to survive the Martian night by utilizing electric heaters powered with solar cells during the day and secondary batteries. The WEB is designed to be impact resistant capable of surviving an impact acceleration pulse equal to or less than 2000 g’s.
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The physiological effects of forces resulting in radial acceleration, sustained linear acceleration, impact, or vibration are identified. Tolerance limits are presented for these forces.
Chronological bibliography on biological effects of impact acceleration