System-Integrated Finite Element Analysis of a Full-Scale Helicopter Crash Test with Deployable Energy Absorbers

A full-scale crash test of an MD-500 helicopter was conducted in December 2009 at NASA Langley's Landing and Impact Research facility (LandIR). The MD-500 helicopter was fitted with a composite honeycomb Deployable Energy Absorber (DEA) and tested under vertical and horizontal impact velocities of 26-ft/sec and 40-ft/sec, respectively. The objectives of the test were to evaluate the performance of the DEA concept under realistic crash conditions and to generate test data for validation of a system integrated finite element model. In preparation for the full-scale crash test, a series of sub-scale and MD-500 mass simulator tests was conducted to evaluate the impact performances of various components, including a new crush tube and the DEA blocks. Parameters defined within the system integrated finite element model were determined from these tests. The objective of this paper is to summarize the finite element models developed and analyses performed, beginning with pre-test predictions and continuing through post-test validation

Estabilización de subrasante modificado con cenizas de tallo de algodón para el camino vecinal La Quebrada, Quilmaná, Cañete, 2021

El presente trabajo de investigación titula: “Estabilización de Subrasante Modificado con Cenizas de Tallo de Algodón para el Camino Vecinal la Quebrada, Quilmaná, Cañete, 2021”. Tuvo el objetivo de Estabilizar la subrasante incorporando cenizas de tallo de algodón (CTA), esto con porcentajes de 2%, 4% y 6% de CTA. La metodología que se aplicó fue tipo de investigación aplicada, nivel de investigación explicativo, diseño experimental, y con un enfoque cuantitativo. Como técnica fue la observación directa y el instrumento se utilizó fichas. La población fue el camino vecinal la quebrada, con una longitud de 6+305 kilómetros. Los resultados que se obtuvo al incorporar el 6% de CTA, se obtuvo un menor índice de plasticidad, con un 2.56%, del ensayo de Proctor Modificado, presenta una mejora con el 2%, obteniendo una máxima densidad seca (MDS) de 1.944 gr/cm3 y un óptimo contenido de humedad (OCH) de 12.70%. Por último, el cálculo de soporte (CBR), con el 6% es donde logramos una mayor resistencia de soporte, con un 24.60%. Se concluye de esta investigación, que la incorporación de las cenizas de tallo de algodón mejora la estabilización de la subrasante, con un suelo arcilloso. Se concluye resultados favorables a la subrasante

Calibration of Airframe and Occupant Models for Two Full-Scale Rotorcraft Crash Tests

Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. Accelerations and kinematic data collected from the crash tests were compared to a system integrated finite element model of the test article. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the second full-scale crash test. This combination of heuristic and quantitative methods was used to identify modeling deficiencies, evaluate parameter importance, and propose required model changes. It is shown that the multi-dimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were compared to test results and the original model results. There was a noticeable improvement in the pilot and co-pilot region, a slight improvement in the occupant model response, and an over-stiffening effect in the passenger region. This approach should be adopted early on, in combination with the building-block approaches that are customarily used, for model development and test planning guidance. Complete crash simulations with validated finite element models can be used to satisfy crash certification requirements, thereby reducing overall development costs

Material Model Evaluation of a Composite Honeycomb Energy Absorber

A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of three DEA components were simulated using the nonlinear, explicit transient dynamic code, LS-DYNA . In addition, a full-scale crash test of an MD-500 helicopter, retrofitted with DEA blocks, was simulated. The four material models used to represent the DEA included: *MAT_CRUSHABLE_FOAM (Mat 63), *MAT_HONEYCOMB (Mat 26), *MAT_SIMPLIFIED_RUBBER/FOAM (Mat 181), and *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM (Mat 142). Test-analysis calibration metrics included simple percentage error comparisons of initial peak acceleration, sustained crush stress, and peak compaction acceleration of the DEA components. In addition, the Roadside Safety Verification and Validation Program (RSVVP) was used to assess similarities and differences between the experimental and analytical curves for the full-scale crash test

Simulating the Response of a Composite Honeycomb Energy Absorber

NASA has sponsored research to evaluate an externally deployable composite honeycomb designed to attenuate loads in the event of a helicopter crash. The concept, designated the Deployable Energy Absorber (DEA), is an expandable Kevlar(Registered TradeMark) honeycomb. The DEA has a flexible hinge that allows the honeycomb to be stowed collapsed until needed during an emergency. Evaluation of the DEA began with material characterization of the Kevlar(Registered TradeMark)-129 fabric/epoxy, and ended with a full-scale crash test of a retrofitted MD-500 helicopter. During each evaluation phase, finite element models of the test articles were developed and simulations were performed using the dynamic finite element code, LS-DYNA(Registered TradeMark). The paper will focus on simulations of two full-scale impact tests involving the DEA, a mass-simulator and a full-scale crash of an instrumented MD-500 helicopter. Isotropic (MAT24) and composite (MAT58) material models, which were assigned to DEA shell elements, were compared. Based on simulations results, the MAT58 model showed better agreement with test

Prototipo de Sistema electrónico diseñado para mejorar la accesibilidad complementado con un sistema de seguridad del domicilio ubicado en el Bo. Reparto Schick

El presente proyecto consiste en diseñar un sistema que controle la iluminación, acceso vehicular y través de cámaras ip monitorear el local con el objetivo de mejorar la seguridad y accesibilidad en la casa M40 ubicado en el Bo. Rene Polanco 4ta etapa Reparto Schick en Managua. En la investigación del proyecto se procedió a efectuar un análisis sobre la temática de inseguridad social que presenta el barrio, los resultados obtenidos de los propietarios del local, consideran “no gozar de una seguridad plena en sus casas”, ya que en muchas ocasiones han intentado sustraer sus pertenencia de valor, cuando sus casas quedan solas por cumplir con sus horarios laborales o bien en sí en horarios de media noche. La adquisición de datos realizó en base a métodos ya antes implementados en otros estudios de caso, obteniendo información de diferentes fuentes como libros, tesis y sitios web. Para el desarrollo del diagnóstico se desarrollaron encuesta en el Bo. Rene Polanco 4ta etapa para determinar la viabilidad y necesidad del sistema de casa automatizada, y posteriormente se aplicó una entrevista al propietario de la casa M40 en la cual se implementó el sistema de control. El sistema de control cuenta con sensores y dos microcontroladores , los sensores están ubicados en puntos estratégicos determinados en base al diagnóstico, estos sensores se encargan de enviar la información a los microcontroladores y este se encargara de procesarla y llevar acabo decisiones de manera automática (encendido de luces, activación de alarma y activación de puerta de garaje automática).Los usuarios tendrán control sobre la casa automatizada a través de una aplicación móvil que se comunicara vía Bluetooth con el sistema para establecer la comunicación usuario-sistema de control, además se elaboró un manual sobre el uso de la aplicación para la configuración del sistem

Preparation of a draft policy for protection against ionizing radiation in Colombia

En el presente escrito se enseñan los resultados de la realización de una pasantía en el Ministerio de la Protección Social de la Republica de Colombia que tuvo por objeto la elaboración de un proyecto normativo para regular la protección contra radiaciones ionizantes a través de un Decreto para definir las competencias de las autoridades de protección radiológica en Colombia y una Resolución para regular el contenido técnico de la Protección. Para lo anterior se atendió a las recomendaciones del Organización internacional de Energía Atómica (OIEA) en su documento “Normas Básicas Internacionales De Seguridad para la Protección contra la Radiación Ionizante y para la Seguridad de las Fuentes de Radiación”, con sujeción a la Ley 16 de 1960 que aprobó la vinculación de Colombia a la OIEA. / Abstract. In the paper hereby presented show the results of the work done in the Ministery of Social Protection in Colombia which had as its objective the preparation of a draft policy to regulate the protection against ionizing radiation. To do so it was made a draft of a Decree, which established the empowerment of each of the two Regulatory Authorities in Colombia and a draft of Resolution which established the content of the technical dispositions for the protection. The source of the drafts was taken from the recommendations of the International Atomic Energy Agency (IAEA), those recommendations are contained in the document titled “International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources”, in complying of the regulations of the Law 16 of 1960 which approve Colombia´s affiliation to the IAEA.Maestro en Salud y Seguridad en el TrabajoMaestrí

Development and Calibration of a System-Integrated Rotorcraft Finite Element Model for Impact Scenarios

Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber (DEA) under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. The presence of this energy absorbing device reduced the peak impact acceleration levels by a factor of three. Accelerations and kinematic data collected from the crash tests were compared to a system-integrated finite element model of the test article developed in parallel with the test program. In preparation for the full-scale crash test, a series of sub-scale and MD-500 mass simulator tests were conducted to evaluate the impact performances of various components and subsystems, including new crush tubes and the DEA blocks. Parameters defined for the system-integrated finite element model were determined from these tests. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the full-scale crash test without the DEA. This combination of heuristic and quantitative methods identified modeling deficiencies, evaluated parameter importance, and proposed required model changes. The multidimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were compared to test results and the original model results. There was a noticeable improvement in the pilot and copilot region, a slight improvement in the occupant model response, and an over-stiffening effect in the passenger region. One lesson learned was that this approach should be adopted early on, in combination with the building-block approaches that are customarily used, for model development and pretest predictions. Complete crash simulations with validated finite element models can be used to satisfy crash certification requirements, potentially reducing overall development costs

Experimental and Analytical Evaluation of a Composite Honeycomb Deployable Energy Absorber

In 2006, the NASA Subsonic Rotary Wing Aeronautics Program sponsored the experimental and analytical evaluation of an externally deployable composite honeycomb structure that is designed to attenuate impact energy during helicopter crashes. The concept, which is designated the Deployable Energy Absorber (DEA), utilizes an expandable Kevlar honeycomb structure to dissipate kinetic energy through crushing. The DEA incorporates a unique flexible hinge design that allows the honeycomb to be packaged and stowed flat until needed for deployment. A variety of deployment options such as linear, radial, and/or hybrid methods can be used. Experimental evaluation of the DEA utilized a building block approach that included material characterization testing of its constituent, Kevlar -129 fabric/epoxy, and flexural testing of single hexagonal cells. In addition, the energy attenuation capabilities of the DEA were demonstrated through multi-cell component dynamic crush tests, and vertical drop tests of a composite fuselage section, retrofitted with DEA blocks, onto concrete, water, and soft soil. During each stage of the DEA evaluation process, finite element models of the test articles were developed and simulations were performed using the explicit, nonlinear transient dynamic finite element code, LS-DYNA. This report documents the results of the experimental evaluation that was conducted to assess the energy absorption capabilities of the DEA

Intensity of Mystical Experiences Occasioned by 5-MeO-DMT and Comparison With a Prior Psilocybin Study

5-MeO-DMT is a psychoactive substance found in high concentrations in the bufotoxin of the Colorado River Toad (Bufo alvarius). Emerging evidence suggests that vaporized 5-MeO-DMT may occasion mystical experiences of comparable intensity to those occasioned by more widely studied psychedelics such as psilocybin, but no empirical study has tested this hypothesis. Data was obtained from 20 individuals (Mage = 38.9, ± 10.7; male = 55%, Caucasian = 85%) who were administered 5-MeO-DMT as part of a psychospiritual retreat program in Mexico. All participants received 50 mg of inhaled vaporized toad bufotoxin which contains 5-MeO-DMT and completed the Mystical Experience Questionnaire (MEQ30) approximately 4–6 h after their session. Administration of 5-MeO-DMT occasioned strong mystical experiences (MEQ30 Overall Mintensity = 4.17, ± 0.64, range 0–5) and the majority (n = 15, 75%) had “a complete mystical experience” (≥60% on all MEQ30 subscales). Compared to a prior laboratory-based psilocybin study, there were no differences in the intensity of mystical effects between 5-MeO-DMT and a high dose (30 mg/70 kg) of psilocybin, but the intensity of mystical effects was significantly higher in the 5-MeO-DMT sample compared to moderate/high dose (20 mg/70 kg) of psilocybin (MEQ30 Total Score: p = 0.02, d = 0.81). Administration of vaporized 5-MeO-DMT reliably occasioned complete mystical experiences in 75% of individuals and was similar in intensity to high dose psilocybin administered in a laboratory setting. The short duration of action may be advantageous for clinical interventions and for studying mystical-type experiences