Dissertations / Theses on the topic 'Helmets – Testing'
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Hakim-Zadeh, Roghieh. "Durability of ice hockey helmets to repeated impacts." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29505.
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This study evaluated the mechanical durability of ice hockey helmets for multiple impacts at defined energy levels. A monorail drop testing apparatus was used to conduct controlled impact tests according to the CSA standard (CAN/CSA-Z262.1-M90). Five ice hockey helmet models were tested, for a total sample of 45 helmets. All helmets were impacted up to 50 times at each of in four different locations (i.e. front, right side, back, and crown), at one of 40, 50 or 60 J of kinetic energies. In general, by increasing the impact energy, the impact acceleration attenuation properties of the helmets was decreased significantly (from 4% to 80%). Although all the helmets meet the CSA standards, attenuation properties were found to be substantially reduced beyond three repeated impacts and above 40 J impact energy. In particular, all helmets showed effective multiple impact attenuation properties at the crown, front, and rear sites; however, poor multiple impact attenuation durability was evident at the side.
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Mojumder, Sounak. "Motorcyclist helmets under oblique impacts and proposal of a new motorcycle helmet testing method." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD014.
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Plusieurs études ont montré que dans les accidents réels, la vitesse d’impact de la tête n’est que rarement normale à la surface et présente une composante tangentielle non négligeable. Aucune norme, à l’heure actuelle ne propose de choc oblique avec enregistrement de l’accélération en translation et en rotation de la fausse tête. Un aspect essentiel de cette recherche a été d’aborder les descriptions d’accidents réels impliquant un motocycliste et un véhicule afin d’évaluer les conditions aux limites de la tête juste avant impact, en termes de vecteur vitesse et de localisation d’impact. Cette étude a permis d’établir le vecteur vitesse possible et de l’angle d’impact de la tête du motocycliste en situation. Une méthode de test pour évaluer le casque a été proposée. Les tests d'impact obliques, sont effectués avec une vitesse d’impact de 8.5 m/s sur une enclume inclinée de 45° permettant la rotation autour de l’axe Y X et Z. Les accélérations 6-D sont implémentés dans le modèle SUFEHM afin d’extraire la déformation axonal maximale et le risque lésionnel. Cette fusion de la méthode expérimentale et numérique donne un avantage par rapport aux normes conventionnelles, tant en termes de conditions d’impact qu’en termes de critère de blessure de la têteIt is well know that in case of accident the head does not only impact perpendicularly to the impacted structure but presents an oblique impact condition. However none of the today helmet standards do integrate oblique impacts with the recording of the dummy head rotational acceleration. An essential aspect of the present research is to simulate real world accident and to compute the victim’s kinematic in order to extract the head impact conditions. In collaboration with University Florence (Italy) 19 cases were considered and it was shown that the head impact velocity vector presents a significative angle. A novel helmet test method has been proposed. Helmeted headfoml is impacting a 45° inclined anvil at a speed of 8.5 m/s and the 6D acceleration versus time curves are introduced into an existing head FEM in order to compute the axon strains and to derive the brain injury risk
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Wall, Robert Edward. "Comparison of international certification standards for ice hockey helmets." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=26765.
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The purpose of this study was to examine the differences between international certification standards for ice hockey helmets. The American Society for Testing and Materials (ASTM), Canadian Standards Association (CSA) and International Organization Standards (ISO) protocols were compared. Only the impact testing methods at ambient temperatures were examined. Four helmet models, currently available to consumers, were used for testing. No significant differences (p $<$ 0.05) were found between the standards in a rank order comparison. Further analysis of differences, with peak linear accelerations separated by impact locations showed significant differences (p $<$ 0.05) between all standards, at five of the six defined impact sites, with no differences being found between standards at the rear site. Post-hoc pairwise multiple comparisons also showed significant performance differences (p $<$ 0.05) between helmet models.
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Sproule, David William. "Evaluation of the Biomechanical Performance of Youth Football Helmets." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/77703.
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Youth and varsity football helmets are currently designed similarly and tested to the same impact standards from the National Operating Committee on Standards for Athletic Equipment (NOCSAE). Youth players have differences in anthropometry, physiology, impact exposure, and potentially injury tolerance that should be considered in future youth-specific helmets and standards. This thesis begins by investigating the current standards and relating them to on-field data. The standard drop tests represented the most severe on-field impacts, and the performance of the youth and varsity helmet did not differ. There likely is not a need for a youth-specific standard as the current standard has essentially eliminated the catastrophic head injuries it tests for. As more is known about concussion, standards specific to the youth population can be developed. The second portion of this thesis compares the impact performance between 8 matched youth and varsity helmet models, using linear acceleration, rotational acceleration, and concussion correlate. It was found that helmet performance did not differ between the youth and varsity helmets, likely attributed to testing to the same standard. The final portion of this feature is aimed at advancing STAR for youth and varsity football helmets by including linear and rotational head kinematics. For varsity helmets, an adult surrogate is used for impact tests which are weighted based on on-field data collected from collegiate football players. For youth helmets, a youth surrogate is used and tests are weighted based on data collected from youth players.Master of Science
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Nyman, Mathias, and Susanna Johansson. "Fatigue testing machine : To simulate daily use on multi-directional impact protection systems in helmets." Thesis, KTH, Hållbar produktionsutveckling (ML), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300121.
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During the development process of a product, tests are typically conducted to ensure the quality of the features of the product before it is made available to the public. The scope of this project was to find a realistic and reliable way to test components in a Multi-Directional Impact Protection System (MIPS) in fully mounted helmets. The reason for this type of testing is to ensure that all components included in the Brain Protection System (BPS) hold up over time in daily use. Therefore, the goal with this project was to design and build a new test machine that could simulate the long-term effects of material fatigue on the MIPS BPS. The machine was able to shake a head with a helmet attached to it to simulate the lifecycle use of a helmet in a shorter time span. The motion of the machine was powered by a stepper motor who is connected to a rocker arm, that transfers a rotational motion to a linear motion, heaving a plate with the head attached to it. The motor is controlled by an Arduino which receives signals from a control panel that enables adjustments to the number of cycles that the machine runs. This report describes the main components, design and function of the machine.Under produktutvecklingsprocesser genomförs tester för att säkerställa produktens olika kvaliteter innan den görs tillgänglig för allmänheten. Syftet med detta projekt var att hitta ett realistiskt och pålitligt sätt att testa komponenter i ett MIPS (Multi-Directional Impact Protection System) i fullt monterade hjälmar. Anledningen till denna typ av testning är att säkerställa att alla komponenter som ingår i Brain Protection System (BPS) håller över tid vid daglig användning. Målet var därför att skapa en ny testmaskin för att simulera de långsiktiga effekterna av förslitning på komponenterna i MIPS BPS. Maskinen kan skaka ett huvud med en hjälm fäst på för att simulera användningen under en hel livscykel hos en hjälm. Maskinen drivs av en stegmotor som är ansluten till en vipparm, vilken i sin tur överför rotationsrörelsen till en linjär rörelse som lyfter plattan med huvudet. Motorn styrs av en Arduino som tar emot signaler från kontrollpanelen vilket möjliggör justeringar av antalet cykler som maskinen kör. Denna rapport redogör för maskinens huvudsakliga komponenter, konstruktion och funktion.
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Stefik, Christopher J. "Effect of protocol mouthguard on VO₂ max in female hockey players using the skating treadmill." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79136.
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Athletes competing in contact sports commonly wear intra-oral dental mouthguards. Data are sparse concerning the influence of a mouthguard on breathing during exercise. We compared VE and VO2 during submaximal and maximal exercise on a skating treadmill (TM) while wearing an intra-oral dental mouthguard. Female varsity hockey players (n = 12) performed two skating tests on a TM with and without a mouthguard (WIPSS Jaw-Joint Protecto(TM)). The players wore the mouthguard during hockey practices prior to collection of ventilation data on the treadmill. Also, the players completed a questionnaire that examined their perceptions of the mouthguard in terms of ventilation, comfort and performance. A 10-point rating scale was used for this evaluation. Two performance tests on the skating treadmill examined the effect of the mouthguard on submaximal and maximal aerobic exercise. The subjects skated for 4 min at 2 submaximal velocities (14 and 16 km·h-1 ) separated by 5 min of passive recovery. A VO2 max test followed the submaximal tests and commenced at 18 km·h-1 with the velocity increasing by 1 km·h-1 every minute until volitional fatigue. VE, VO2, VCO 2 and RER were analyzed using a Sensor Medics 2900 metabolic cart. Two-way (2 conditions x 3 velocities) repeated measures ANOVAs were used to examine differences in VE, VO2 and HR. Ventilation was unchanged when skating at the two submaximal velocities. VO2 max was 48.8 ml·kg-1·min-1 using the intra-oral mouthguard and was 52.4 ml·kg-1·min -1 without a mouthguard. VE max was 108.5 L·min -1 using the intra-oral mouthguard and was 114.1 L·min -1 without a mouthguard. The results showed that VE max and VO2 max were lower using the mouthguard compared to the no mouthguard condition.
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Godfrey, Nicholas P. M. "Mathematical modelling of a helmeted head under impact." Thesis, Brunel University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292391.
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Schuster, Michael Jeremy. "PHYSICAL TESTING OF POTENTIAL FOOTBALL HELMET DESIGN ENHANCEMENTS." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1596.
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Football is a much loved sport in the United States. Unfortunately, it is also hard on the players and puts them at very high risk of concussion. To combat this an inventor in Santa Barbara brought a new design to Cal Poly to be tested.
The design was tested in small scale first in order to make some preliminary conclusions about the design. In order to fully test the helmet design; however, full scale testing was required. In order to carry out this testing a drop tower was built based on National Operating Committee on Standards for Athletic Equipment, NOCSAE, specification. The drop tower designed for Cal Poly is a lower cost and highly portable version of the standard NOCSAE design. Using this drop tower and a 3D printed prototype the new design was tested in full scale.
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Cobb, Bryan Richard. "Laboratory and Field Studies in Sports-Related Brain Injury." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73208.
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The studies presented in this dissertation investigated biomechanical factors associated with sports-related brain injuries on the field and in the laboratory. In the first study, head impact exposure in youth football was observed using a helmet mounted accelerometer system to measure head kinematics. The results suggest that restriction on contact in practice at the youth level can translate into reduced head impact exposure over the course of a season. A second study investigated the effect of measurement error in the head impact kinematic data collected by the helmet mounted system have on subsequent analyses. The objective of this study was to characterize the propagation of random measurement error through data analyses by quantifying descriptive statistic uncertainties and biases for biomechanical datasets with random measurement error. For distribution analyses, uncertainties tend to decrease as sample sizes grow such that for a typical player, the uncertainties would be around 5% for peak linear acceleration and 10% for peak angular (rotational) acceleration. The third and fourth studies looked at comparisons between two headforms commonly used in athletic helmet testing, the Hybrid III and NOCSAE headforms. One study compared the headform shape, particularly looking at regions that are likely to affect helmet fit. Major differences were found at the nape of the neck and in the check/jaw regions that may contribute to difficulty with fitting a helmet to the Hybrid III headform. For the final study, the impact responses of the two headforms were compared. Both headforms were mounted on a Hybrid III neck and impacted at various magnitudes and locations that are representative of impacts observed on the football field. Some condition-specific differences in kinematic parameters were found between the two headforms though they tended to be small. Both headforms showed reasonable repeatability.Ph. D.
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Carnevale, Lon Sergio Christian. "A new helmet testing method to assess potential damages in the Brain and the head due to rotational energy." Thesis, KTH, Skolan för teknik och hälsa (STH), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154206.
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Preservation and protection of the head segment is of upmost importance due to the criticality of the functions entailed in this section of the body by the brain and the nervous system. Numerous events in daily life situations such as transportation and sports pose threats of injuries that may end or change a person’s life. In the European Union, statistics report that almost 4.2 million of road users are injured non-fatally, out of which 18% is represented by motorcyclist and 40% by cyclists, being head injuries 34% for bicyclists, and 24% for two-wheeled motor vehicles. Not only vehicles, are a source of injuries for the human head according to the injury report, 6,1 million people are admitted in hospitals for sports related injuries, where sports such as hockey, swimming, cycling presented head injuries up to 28%, 25% and 16% respectively (European Association for Injury Prevention and Safety Promotion, 2013). According to records the vast majority of head crashes result in an oblique impact (Thibault & Gennarelli, 1985). These types of impacts are characterized for involving a rotation of the head segment which is correlated with serious head injuries. Even though there is plenty of evidence suggesting the involvement of rotational forces current helmet development standards and regulations fail to recognize their importance and account only for translational impact tests. This thesis contains an evaluation for a different developed method for testing oblique impacts. In consequence a new test rig was constructed with basis on a guided free fall of a helmeted dummy head striking an oblique (angled) anvil which will induce rotation. The results obtained are intended to be subjected to a comparison with another oblique test rig that performs experiments utilizing a movable sliding plate which when impacted induces the rotation of a dropped helmeted dummy head. The outcome will solidify the presence of rotational forces at head-anvil impact and offer an alternative testing method. After setting up the new test rig; experiments were conducted utilizing bicycle helmets varying the velocities before impact from 5m/s to 6m/s crashing an angled anvil of 45°. Results showed higher peak resultant values for rotational accelerations and rotational velocities in the new test rig compared to the movable plate impact test, indicating that depending on the impact situation the “Normal Force” has a direct effect on the rotational components. On the other hand a performed finite element analysis predicted that the best correlation between both methods is when the new angled anvil impact test is submitted to crashes with a velocity before impact of 6 m/s at 45° and the movable sliding impact test to a resultant velocity vector of 7,6m/s with an angle of 30° . In conclusion the new test method is meant to provide a comparison between two different test rigs that will undoubtedly have a part in the analysis for helmet and head safety improvements.
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Swift, Nathan Butler IV. "HEDGEMON: A HEDGEHOG-INSPIRED HELMET LINER." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459380535.
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Vögele, Christian [Verfasser], Helmut [Akademischer Betreuer] Krcmar, Helmut [Gutachter] Krcmar, and Alexander [Gutachter] Pretschner. "Automatic Extraction and Selection of Workload Specifications for Load Testing and Model-Based Performance Prediction / Christian Vögele ; Gutachter: Helmut Krcmar, Alexander Pretschner ; Betreuer: Helmut Krcmar." München : Universitätsbibliothek der TU München, 2018. http://d-nb.info/116262115X/34.
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Scheer, Marsel [Verfasser], Helmut [Akademischer Betreuer] Finner, and Arnold [Akademischer Betreuer] Janssen. "Controlling the Number of False Rejections in Multiple Hypotheses Testing / Marsel Scheer. Gutachter: Helmut Finner ; Arnold Janssen." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2013. http://d-nb.info/1031074996/34.
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Thiem, Annette [Verfasser], and Helmut [Akademischer Betreuer] Schubert. "Entwicklung und Testung eines resorbierbaren Trägermaterials für die Behandlung von artikulären Knorpeldefekten / Annette Thiem. Betreuer: Helmut Schubert." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2011. http://d-nb.info/1017154163/34.
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Zimmermann, Julian Johannes [Verfasser], Thomas R. [Akademischer Betreuer] [Gutachter] Tölle, and Helmut [Gutachter] Friess. "Zur Typologie des Schmerzes bei Patienten mit Pankreaskarzinom und chronischer Pantkreatitis: Ergebnisse mit der Quantitativen Sensorischen Testung und dem Schmerzfragebogen painDETECT / Julian Johannes Zimmermann. Betreuer: Thomas R. Tölle. Gutachter: Helmut Friess ; Thomas R. Tölle." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1107543649/34.
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(6577457), Kevin G. McIver. "Engineering Better Protective Headgear for Sport and Military Applications." Thesis, 2019.
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Recent applications of medical imaging, advanced polymers, and composites have led to the development of new equipment for athletes and soldiers. A desire to understand the performance of headgear that resists impacts ongoing since the 1970’s has found more traction in recent years with the usage experimental models that have a greater degree of bio-fidelity. In order to determine which features of helmets from different sports (Soccer, Lacrosse, Football, and Hockey) were tested on a Hybrid III 50th Percentile Male headform with an accelerometer rig at the center of mass.Testing was performed by administering impacts to the headform with an impulse hammer that provides transient force data in order to quantify inputs and outputs of the system to develop a non-dimensional transfer function. Helmet performance is compared by sport worn in order to determine desirable manufacturing features and develop prototype helmets that outperforms current athletic equipment.
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Nakaza, Edward Takeshi Safety Science Faculty of Science UNSW. "Assessment of injury risks associated with wearing the enhanced combat helmet and night vision goggle - driver: frontal vehicle collision study." 2007. http://handle.unsw.edu.au/1959.4/40484.
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The requirement to operate vehicles in low light and/or night environments whilst wearing night vision goggle (NVG) systems has become increasingly common during military operations. There is very limited research investigating injury risks associated with these systems during ground vehicle collisions. This study examined the injury risks associated with wearing the Australian Defence Force - Enhanced Combat Helmet (ECH) and NVG system, in frontal vehicle collisions. This project consisted of two components: (1) crash tests using a sled and (2) numerical simulations of impacts. Four dynamic sled tests were conducted using a 50th percentile, male, Hybrid III dummy positioned on a rigid seat. Frontal impact tests were performed at a 40 km/h change in velocity (*v) and 20 g deceleration. The test configurations were as follows: (a) Base; (no helmet or additional equipment); (b) ECH; and, (c) ECH and NVG. Condition (c) was carried out twice, to determine repeatability. The sled test protocols were reconstructed precisely with the numerical simulation package MADYMO and the simulations were shown to correlate well with the experimental results. Using this validated model, four parametric studies were undertaken to assess the influence of counterweights, seat cushion, seatbelt pre-tensioner, and the vehicle's *v and acceleration on injury risks. The study found that neck loads were within acceptable limits, with the exception of the neck extension moment, which was exceeded for all NVG conditions. Based on the parametric studies, no major improvements were observed in the neck extension moments with the use of counterweights or a seat cushion. In contrast the use of a seatbelt pre-tensioner was observed to decrease greatly this neck injury risk in certain scenarios. The study also identified that a *v of 15 km/h and peak acceleration of up to 14 g were required to keep the neck extension moment below the prescribed injury criteria. However, the high neck extension moment values may have been partially attributable to the stiff Hybrid III neck. This study identified a possible injury mechanism for soldiers using the ECH and NVG system during specific impact scenarios. The method applied in this project was designed to be repeatable.
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Kamp, Michael Anthony. "Development and Testing of a Self-Contained, Portable Instrumentation System for a Fighter Pilot Helmet." 2009. http://trace.tennessee.edu/utk_gradthes/535.
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A self-contained, portable, inertial and positional measurement system was developed and tested for an HGU-55 model fighter pilot helmet. The system, designated the Portable Helmet Instrumentation System (PHIS), demonstrated the recording of accelerations and rotational rates experienced by the human head in a flight environment. A compact, self-contained, “knee-board” sized computer recorded these accelerations and rotational rates during flight. The present research presents the results of a limited evaluation of this helmet-mounted instrumentation system flown in an Extra 300 fully aerobatic aircraft. The accuracy of the helmet-mounted, inertial head tracker system was compared to the aircraft-mounted referenced system. The ability of the Portable Helmet Instrumentation System to record position, orientation and inertial information in ground and flight conditions was evaluated. The capability of the Portable Helmet Instrumentation System to provide position, orientation and inertial information with sufficient fidelity was evaluated. The concepts demonstrated in this system are: 1) calibration of the inertial sensing element without external equipment 2) the use of differential inertial sensing equipment to remove the accelerations and rotational rates of a moving vehicle from the pilot’s head-tracking measurements 3) the determination of three-dimensional position and orientation from three corresponding points using a range sensor. The range sensor did not operate as planned. The helmet only managed to remain within the range sensor’s field of view for 37% of flight time. Vertical accelerations showed the greatest correlation when comparing helmet measurements to aircraft measurements. The PHIS operated well during level flight.