Automobile Airbag Research Articles

Engineering Origami: A Systematic Literature Review in the context of Space Technology, Design, and Applications

Abstract: Origami is the ancient art of Japanese paper folding. For years it has been used to create stunning works of art. But origami has also been used in more surprising ways, like car airbags, stents, and even space exploration. Origami is a bit more than just a paper crane. Engineers use it for use, solve the interesting problems. Origami teaches how to fold very large thin sheets into very small spaces. And that's exactly what space engineers need. The reason for incorporating origami for space applications is to launch structures in space that are just amazingly big using flashers, starshade folding, tessellations, etc. So being able to fold these structures such that they fit neatly within our rocket and then unfold when they get to space. The researcher has attempted to do a literature review and to demonstrate how origami can be used in aerospace engineering and related fields. Innovative aerospace solutions such as morphing aircraft wings and deployable space constructions are made possible by the principles of origami. Using sophisticated modelling and simulation tools is essential for creating intricate origami structures for aerospace applications.

Airborne metal nanoparticles released by azides detonation: determination and potential public exposure

Metal azides are highly energetic materials that release a large amount of gas upon detonation. They also release metal particles, generating an aerosol. The most common azide is sodium azide (NaN3), which is used nowadays in car airbags. If the decomposition is not complete, harmful azide particles might be inhaled. Heavy metal azides find application as a primary explosive (primer) in ammunition. Public health officials have raised concerns about heavy metal particles released during training in shooting ranges. We identify a lack of knowledge on airborne metal particles properties released from azide detonation and on the analytical methods applied to characterize them. As a case study, we detonated milligram amounts of silver azide, copper azide, and a mixture of them in a glove box. We then analyse the airborne particles with an ensemble analytical setup, able to measure real-time their particle size distribution and chemical composition. We detected spherical metal nanoparticles in the range of 2–500 nm. These findings and the developed analytical tools may allow identifying airborne nanoparticles the passenger compartments of vehicles after airbag activation as well as in indoor shooting ranges, contributing to the evaluation of public health risks.

Summary of influences that led to introduction of frontal airbags on US passenger vehicles

Objective The history of airbags for occupant protection in frontal crashes is reviewed from the perspective of a former Senior Executive at NHTSA from the early 1970’s to the late 1980’s. This paper summarizes the factors that led to regulatory delays as well as those that led to voluntary adoption of airbags by several manufacturers. Methods The regulatory history and interactions with airbag suppliers and vehicle manufactures is recounted citing key steps in the evolution of frontal airbags. Results When the Advanced Notice of Proposed Rulemaking for Standard 208, “Occupant Protection” was issued on July 2, 1969 the Safety Agency anticipated that the industry response would provide automatic frontal crash protection from airbags that deployed to protect all front seat occupants from injury in severe frontal crashes. It was not until, September 1, 1998 that airbags were required in all cars and light trucks. The interim 29 years involved a series of stops and starts during which most of the original airbag suppliers lost interest and abandoned the airbag market. The issues associated with airbags and their place in Standard 208 were directly influenced by interventions from the President, the Congress, the Supreme Court, Secretaries of Transportation, NHTSA Administrators, the Presidents of US Auto Companies and Senior Executives of Insurance Companies. Conclusion In 1966, there was support from the US auto industry for a single source of safety regulations that apply to new vehicles sold in the US. This is evidenced by the unanimous passage by the House of Representatives and Senate of the Law that created the Federal auto safety regulatory framework. The Law also required seatbelts in new cars and prohibited States from making separate safety rules. However, the large safety benefits offered by seatbelts were negated because they were rarely used. Consequently, finding ways of providing high levels of protection without requiring action by occupants became a goal of the new Safety Agency. The airbag offered the possibility of achieving that goal. From the initial airbag notice of proposed rulemaking on July 2, 1969, Safety Agency required 2 years to resolve objections before a final Standard 208 could be issued (on July 8,1971). The subsequent industry opposition to the Standard 208 employed Presidential influence and Court suits to cause a 5½ year delay until the Coleman Decision on December 6, 1976. Changes in regulatory approach of the Ford, Carter, and Reagan Administrations and associated Court suits caused another 7½ year delay until the Dole Decision on July 17, 1984. It required another 7 ½, until December 18, 1991, for market forces to reduce industry opposition to airbags and permit Congress to pass a law that mandated them. Another 6½ years of lead time was required before all cars and light trucks were required to meet the airbag standard. During the mid and late 1980’s vehicle safety ratings, seatbelt use laws, and Vince and Larry PSA’s had all acted to increase safety awareness and safety belt use. Consequently, added public demand for vehicle safety features slowly developed. Changes in economic incentives encouraged a number of vehicle lines to install driver airbags as standard equipment and the feature was being widely advertised by Chrysler. This combination of events made it possible for Congress to pass and President Bush 41 to sign legislation requiring airbags in cars and light trucks by September 1, 1998 – more than 29 years after the initial rulemaking notice in 1969.

Clinical Diagnosis and Management of Traumatic Acute Intracranial Subdural Hematoma: Review Article

Traumatic brain injury (TBI) is the leading cause of death and disabling conditions in persons. The frequency and severity of head injuries have both decreased as a result of numerous industrial safety improvements, the installation of airbags in automobiles, and the enforcement of speed restrictions. TBI survivorship has increased due to advancements in emergency response times and acute care, but this has also increased the need for accurate ways to detect individuals at risk of subsequent diseases. Pupil reactivity, the Glasgow Coma Scale, and head computed tomography are currently the main clinical signs indicating the existence of brain damage. The current review will cover the clinical presentation, diagnosis, and treatment of TBI,

The Inside Out of Flies

There can be absolutely no doubt that author and researcher Erica McAlister finds flies fascinating. The enthusiasm and joy with which she discusses her Diptera subjects is infectious; although readers might not end up truly loving flies, as McAlister does, they will certainly come away with appreciation for the evolutionary wonder of this ubiquitous group of insects. McAlister’s previous book, The Secret Life of Flies, examined fly behavior. This companion volume, The Inside Out of Flies, examines fly anatomical adaptations. The first chapter describes “pre-adulthood” (development of flies, from egg through adulthood); the following eight chapters focus on adult anatomy, working their way from the head (with separate chapters on the antennae and the mouthparts) to the end of the abdomen (the terminalia). In each chapter the anatomical aspects and evolutionary adaptations shown in each body part are carefully presented with many unique examples. The book itself is physically lovely: great attention has been paid to layout, and visuals are clear and informative.Open this book to any page, and you will find something astounding about flies. Flies being flies, this could be somewhat revolting (maggot extra-oral digestion and tissue debridement) or amazing (“mag-bot” robots that mimic maggot motion to deliver pharmaceuticals to specifically targeted locations in the body). Did you know that some flies don’t even have functional mouthparts as adults? Or that flies have sensory hairs that literally “taste” bitter and sweet molecules in the atmosphere? Or that some female flies have eversible sacs (McAlister describes them as “resembling car air bags”) that emit pheromones and make the female’s body look bigger to entice males to mate? The almost unending examples are fascinating, though they are in a way the source of the book’s biggest fault. Although McAlister undoubtedly felt she omitted many examples important to dipterists (such as the global attendees at “fly school” described in the end chapter), the more general student of biology would have benefitted from a more selective presentation. Example after example with scientific names, classifications, and adaptations lead at times to reader fatigue. Overall, however, this is a wonderful volume, of potential interest and use to a wide variety of readers interested in biology, entomology, behavior, and evolution.

Elucidating the mechanisms associated with the anaerobic biotransformation of the emerging contaminant nitroguanidine

Nitroguanidine (NQ) is a constituent of gas generators for automobile airbags, smokeless pyrotechnics, insecticides, propellants, and new insensitive munitions formulations applied by the military. During its manufacture and use, NQ can easily spread in soils, ground, and surface waters due to its high aqueous solubility. Very little is known about the microbial biotransformation of NQ. This study aimed to elucidate important mechanisms operating during NQ anaerobic biotransformation. To achieve this goal, we developed an anaerobic enrichment culture able to reduce NQ to nitrosoguanidine (NsoQ), which was further abiotically transformed to cyanamide. Effective electron donors for NQ biotransformation were lactate and, to a lesser extent, pyruvate. The results demonstrate that the enrichment process selected a sulfate-reducing culture that utilized lactate as its electron donor and sulfate as its electron acceptor while competing with NQ as an electron sink. A unique property of the culture was its requirement for exogenous nitrogen (e.g., from yeast extract or NH4Cl) for NQ biotransformation since NQ itself did not serve as a nitrogen source. The main phylogenetic groups associated with the NQ-reducing culture were sulfate-reducing and fermentative bacteria, namely Cupidesulfovibrio oxamicus (63.1% relative abundance), Dendrosporobacter spp. (12.0%), and Raoultibacter massiliens (10.9%). The molecular ecology results corresponded to measurable physiological properties of the most abundant members. The results establish the conditions for NQ anaerobic biotransformation and the microbial community associated with the process, improving our present comprehension of NQ environmental fate and assisting the development of NQ remediation strategies.

Adaptive airbag system for increased evacuation safety

This short communication is aimed at indication of asignificant problem to be solved by researchers working in the field of engineering structures. The contribution concerns avery important application of a rescue cushion, which is an airbag system devoted to the impact mitigation appearing during evacuation of people from heights. Although, a very similar in the principle of their operation, car airbags have been thoroughly tested, rescue cushions have not received sufficient attention. It should be emphasized that the performance of the actually operated devices is far from sufficient and even fatal accidents occur. The authors identified the problem and have initiated a study, which includes numerical simulation and experimental validation of the impact absorption process, as well as the elaboration of a suitable adaptive solution.

Car-Based External Airbag for Bicyclist Protection in Side Impacts

<div class="section abstract"><div class="htmlview paragraph">Cyclist injuries and fatalities are a world-wide concern and often a consequence of interaction with cars. The MICA2 Project (Modelling of Interactions between Cyclists and Automobiles) is aimed at protecting bicyclists from getting injured by a passing car. This study addresses the need for new protective safety systems through the development and testing of a novel external car airbag. The airbag was designed to add protection to the center side part of the car, in the B-pillar area, to protect the head of a bicyclist impacting a car in this area. Two methods were used to evaluate performance of the system. For full system tests, a Hybrid III 50<sup>th</sup> percentile male dummy was seated on a city bike and projected into the side of a car at either 30°, 60° or 90° to the car side. In additional component tests an adult pedestrian headform was launched towards the roof rail or B-pillar structure of the car. The highest injury risk was found in a perpendicular (90 degree) impact between the bicycle and car. In oblique crashes the bicycle slid along the side of the car and that decreased the linear accelerations in the head. Glancing collisions (30 degree) resulted in low injury risk as there was no direct head impact. The airbag was very effective in reducing the HIC for the dummy or headform, by about 30%, in the 90 degree impact case with dummy and more than that with the headform.</div></div>

One-shot device test data analysis using non-parametric and semi-parametric inferential methods and applications

A one-shot device, such as an automobile airbag, electro-explosive unit or munition, is a product that can be used only once. Its actual lifetime is unobservable, rendering the corresponding reliability analysis quite challenging. In this paper, two non-parametric methodologies—maximum likelihood estimation via EM-algorithm and Nelson–Aalen based estimation are developed for identical testing environment on one-shot devices. The EM-algorithm is usually used for unobserved failure times under some specific parametric models. But, here the EM-algorithm is adopted for the number of failures in each time interval in a non-parametric manner. Next, a semi-parametric approach, based on proportional hazards assumption, is developed for nonidentical testing environments, such as under an accelerated life-test. A Monte Carlo simulation study is then carried out for evaluating the performance of the inferential methods developed here. Finally, two data sets are analyzed for illustrative purpose.

Design and implementation of MOEMS based optical diaphragm using Photonic Crystal for the prevention of barotrauma

When there is stress on the eardrum because of a change in air pressure is known as Barotrauma. If there is excessive pressure than 20 KPa, damage to the eardrum may occur. During air travel, Barotrauma can occur due to pressure differences at high altitudes. This paper presented a MOEMS based pressure sensor using Photonic crystal. Two variants of sensor designs are a ring resonator and a semicircular resonator structure. Some of the potential use of a nanoscale pressure sensor is to measure the pressure inserted on the eardrum during scuba diving and the impact of an automobile airbag. The novelty of the work is to detect low-pressure between 5 KPa and 20 KPa. When applying pressure to the sensor, a variation in the refractive index occurs proportional to the stress imparted. The change in optical property caused the shift in the wavelength for pressure level. The impact of stress on a sensor placed on the diaphragm separating two media (air and water) were analyzed using 3D modelling and simulations. The designed sensor can be placed in an earplug to monitor pressure change. The Q-Factor observed is 3877.80 for ring structure and 4933.77 for semicircular structure. The novelty of the work is the development of Photonic Crystal based pressure sensor for Barotrauma detection and reduction of the sensor’s size.

Modeling of dynamic interaction of a fabric airbag with an anthropometric dummy

In this paper, a physical and mathematical model of interaction between a fabric expanding automobile airbag and biological objects is formulated. Bioobjects are represented using finite element models of anthropometric dummies of the Hybrid III 50th Male type. As a model of the airbag material, a model of multi-layer fabric orthotropic material was used. The method of corpuscular particles was used for numerical simulation of the airbag functioning in the LS-DYNA multiphysics simulation software package. The results of calculating the dynamic interaction of an expanding airbag with three standing dummies are presented.

Dynamic abuse testing of airbag system for passenger car under vehicle-road conditions and identification method for high-risk triggering items

Determination of the triggering conditions for automobile airbags is a complex problem because vehicles often run under transient conditions due to the dynamic influence from varying road conditions. The research into malfunctions of automobile airbags is an important and challenging topic. In this work, the peak acceleration and moving window integration algorithms were used to obtain the high-risk abuse items from a test matrix that consisted of 111 items which were under multiple road environment excitation, including condition categories for typical roads, curb striking, potholes and drains, and roadblocks. A novel multi-channel data reduction method and improved clustering method based on abuse probability sorting were proposed, and based on the specific characteristic constraints for the automobile airbag malfunction test results, by construction of a false triggering probability model and discussion of the weight factors of the two algorithms, importance rankings for the high-risk false action items were realized based on the relative probability. Finally, 53 high-risk abuse items were identified from a large set of 111 test items through 10-channel acceleration sensors. After analysis and comparison of the test condition details, conclusions of high-risk items are drawn with regard to the vehicle-road excitation that affects airbag abuse. The consistency of the identification results with the Chinese national standard verifies the accuracy and effectiveness of the proposed method.

MECHANICAL PROPERTIES OF ALUMINIUM ALLOYS AT HIGH STRAIN RATE

The split Hopkinson's pressure bar test is a part of a group of testing methods used to determine dynamic behavior of various materials in an interval of strain rate from 100 s-1 to 103 s-1. The article describes the practical application of the testing method for aluminum alloy EN AW 6082. This alloy is used for cold-extruded parts (components of car airbags). Since the strain rate of cold forming technologies reaches up to 1000 s-1, it is necessary to determine the material´s behavior at these strain rate values.

Experimental and Numerical Investigation of PA66 Fabrics Coated/Uncoated PVC by Biaxial Tensile Tests

Automobile airbags have become mandatory safety components in many countries. In this study, the PA66 (polyamide 66) airbag fabric was tested with and without a surface coating of PVC (polyvinyl chloride). Cyclic loading and unloading experimental conditions were defined according to the loading characteristics of the airbag deployment process. To determine mechanical properties such as elastic modulus and stress-strain curves for the two materials, biaxial loading/unloading cyclic tensile tests were carried out using a DIC (Digital Inspection Camera) to monitor the field strain process. Quadratic polynomial regression was used to fit material constitutive models of each loading and unloading process to the test data. The material subroutine VUMAT was encoded and applied to the simulation of the biaxial tensile testing of the fabrics. There was good agreement between the experimental and simulation results, which verifies that the quadratic polynomial constitutive material model is suitable for the study of coated and uncoated PA66 automobile airbag fabric. Hence, the material behaviour of automobile airbag fabrics can be modelled accurately.

THE INFLUENCE OF FACTORS ON THE CHARACTERISTICS OF THE GAS-GENERATING PYROTECHNIC MIXTURE BASED ON SODIUM AZIDE AND POTASSIUM NITRATE

This paper presents the influence of composition contents on several energetic characteristics (combustion heat, gaseous volume) of the gas-generating pyrotechnic mixture containing sodium azide, potassium nitrate. Moreover, the effect of particle size of potassium nitrate and pressed density of the pyrotechnic mixture on the combustion rate is also investigated. Based on the received experimental and theoretical results, the optimal sodium azide/potassium nitrate ratio of 76/24 with 0.04 ÷ 0.06 mm of particle size of potassium nitrate at the pressed density of 1.7 g/cm3 is determined. The pyrotechnic mixture can be used for automobile airbags and other applications.

Reliability estimation for one-shot devices under cyclic accelerated life-testing

A one-shot device, like an automobile airbag, is a product or an equipment that can be used only once. Better quality and longer lifetime of one-shot devices nowadays increase the cost of life test experiment under normal operating condition. Cyclic stress test, adopted in life-testing experiments by increasing stress levels to induce more failures, has been used to investigate the reliability analysis of one-shot devices based on Coffin–Manson principle. However, the Coffin–Manson model only considers temperature change in each cycle. Moreover, it assumes that the reliability is independent of the cycling frequency, which may not be a realistic assumption in practice. Birnbaum–Saunders distribution, originally developed to model fatigue failure under cyclic loading, has been used widely to model lifetime data. As the Norris–Landzberg model is proposed for modeling fatigue life due to cyclic temperature fluctuation, it is used in this work together with Birnbaum–Saunders distribution for modeling lifetimes of one-shot devices under accelerated life-tests with different cyclic temperature fluctuations. It contains the Coffin–Manson model as a special case. Inferential methods for model parameters, reliability and mean lifetime are developed in this paper. Simulation study and model discrimination are carried out to evaluate the performance of the proposed model and inferential methods. Finally, an example is presented to illustrate the model and the inferential results developed here.

Severe facial fractures due to airbag deployment without utilization of a seat belt: A case report

This report is about a man of 25 years old (175 cm, 90 kg) who sustained bilateral Le fort I, II, and III fractures because of an inflating car airbag. Despite the fact that airbags harshly reduce both the mortality and morbidity from crashes as intercept frontal collisions, but with increasing use of airbags, increasing number of injuries caused by these devices is inevitable. Reports about serious injuries and even death due to airbag deployment

Development of a compact pulsed ejector: performance assessment from measured aerodynamic characteristics

The investigation aims at the development of an efficient ejector applicable to the inflation system of automobile airbags. The work consists in the design of the ejector together with an appropriate testing facility and a measurement complex. The experiment is planned in three parts, measurement of pressure fields, high-speed video recording of the airbag inflation using the designed ejector, and measurement of the entrainment (aspiration) ratio. For that, a few basic elements are built. They are the pneumatic facility with a specially designed high-speed valve as its key element, the data acquisition, and processing system controlled remotely to analyze pressure probe rake signals, and the stand to measure entrainment ratio values depending on the ejector geometry and motive pressure values.To satisfy the given engineering requirements, supersonic pulse aspirators are developed in various design versions, manufactured, and tested in the Laboratory for Advanced Aerodynamics. Analysis of a number of experimentally obtained results showed their good mutual concordance and a possibility to get the “cold-gas” aspiration ratio, A=3.16 – 1.57, depending on the motive pressure. The new device has obvious advantages compared to the conventional pyrotechnic type: (1) provides their safe operation with big airbags of the autonomous car, (2) eliminates injuries to occupants since aspirated airbags stop inflating on contact with any object within a vehicle.

Core-Shell Structured Nanoenergetic Materials: Preparation and Fundamental Properties.

Energetic materials, including explosives, pyrotechnics, and propellants, are widely used in mining, demolition, automobile airbags, fireworks, ordnance, and space technology. Nanoenergetic materials (nEMs) have a high reaction rate and high energy density, which are both adjustable to a large extent. Structural control over nEMs to achieve improved performance and multifunctionality leads to a fascinating research area, namely, nanostructured energetic materials. Among them, core-shell structured nEMs have gained considerable attention due to their improved material properties and combined multiple functionalities. Various nEMs with core-shell structures have been developed through diverse synthesis routes, among which core-shell structured nEMs associated with explosives and metastable intermolecular composites (MICs) are extensively studied due to their good tunability and wide applications, as well as excellent energetic (e.g., enhanced heat release and combustion) and/or mechanical properties. Herein, the preparation methods and fundamental properties of the abovementioned kinds of core-shell structured nEMs are summarized and the reasons behind the satisfactory performance clarified, based on which suggestions regarding possible future research directions are proposed.

In Situ Synthesized MEMS Compatible Energetic Arrays Based on Energetic Coordination Polymer and Nano-Al with Tunable Properties.

Integrating energetic materials with a microelectromechanical system (MEMS) to achieve miniaturized integrated smart energetic microchips is promising. The potential applications include actuation in lab-on-a-chip devices, ignition in automobile airbags, propulsion and attitude control of micro-/nano-satellites, and miniaturized electro-explosive devices. In this work, a new type of MEMS-compatible energetic arrays was in situ realized on a copper substrate, which comprised a new energetic coordination polymer (ECP; Cu1.5C2N8O2·H2O) with tunable nanostructures and a nano-aluminum (nano-Al) covering layer. The composition, morphology, and energetic characteristics of the energetic arrays can be easily tuned by adjusting the reaction time. The maximum heat release of 1850.2 J/g in thermal analysis and the intense flame in open burning experiment proved its excellent exothermic and combustion performance. A closed-bomb experiment further revealed that the ECP@nano-Al energetic arrays supported on Cu(OH)2 nanorods had a peak pressure (5.5 MPa) and a pressure duration (0.5 s) more than twice those of nanoscale Al/CuO powder because of the introduction of gas elements (e.g., C, H, and N). A preliminary impulse experiment was also conducted through the torsion pendulum method. The displacement of the torsion pendulum in the micrometer scale proved the potential application of the energetic arrays in micropropulsion systems. Overall, this work can serve as a reference for the synthesis and applications of ECPs.