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.

Trots att det har utvecklats skyddsutrustning som skyddar hjärnan mot farlig roterande kinematik inom flera områden, finns ännu ingen utrustning som skyddar boxare mot den typen av våld. Syftet med arbetet var att göra olympisk boxning och träning säkrare. Målet var att utveckla en handske som reducerar töjningen i hjärnan med minst 20 %. I det här arbetet utvecklades och testades ett antal boxningshandskar med implementerade glidskikt som skulle reducera töjningen i hjärnan som uppstår när huvudet utsätts för roterande kinematik. Testerna genomfördes med en linear impactor som slog handskarna mot ett testhuvud. Testhuvudet samlade mätdata med hjälp av nio accelerometrar. Två av prototyperna reducerade töjningen med mer än 20 % vid ett eller flera tester men de hade brister i användningsbarhet. Ingen av prototyperna uppfyllde alla mål och därför kan ingen prototyp rekommenderas för vidareutveckling men det kan konstateras att det finns potential i grundidén. / Although protective equipment has been developed that protects the brain against dangerous rotating kinematics in several areas, no equipment is yet available to protect boxers against this type of violence. The purpose of this work was to make Olympic boxing and training safer. The goal was to develop a glove that reduces the strain in the brain by at least 20 %. In this work, a number of boxing gloves with implemented sliding layers were developed and tested, which would reduce the strain in the brain that occurs when the head is subjected to rotational kinematics. In the tests a linear impactor was used, which hit the gloves against a test head. The test head collected data using nine accelerometers. Two of the prototypes reduced the strain by more than 20% in one or more tests, but they lacked in usability. None of the prototypes met all objectives and therefore no prototype can be recommended for further development, but it can be stated that there is potential in the basic idea. / <p>Betyg 2020-07-11</p>

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