Development of an instrumented test dummy for the impact evaluation of protective devices
Safety in skiing is a complex issue that is often correlated with the efficiency of protective devices and of safety barriers, either in the case of accidental falls or in the case of collisions between skiers or with fixed obstacles. Injuries due to falls or to collisions could be reduced if an improved design of safety materials is carried out. Protective devices should be evaluated during suitable dynamic tests that can simulate the speed of the impact and the complex loading conditions. Complexity is enhanced by the peculiar geometry of the human body and the variability of body postures during falls or collisions.
The possibility of a functional dynamic evaluation of performance levels in typical protective devices will be improved by the development of an anthropometric dummy with accelerometers and load sensors applied to important body locations such as the head and the thorax. Like in the automotive industry, the dummy will be used to simulate impacts against typical safety barriers like nets and mats or possible falls, with realistic speed and equipment conditions.
The dummy will be suitable of wearing different protective equipment (helmets, mouthguards, kneebraces etc.) and impacting the obstacles with different postures: data collected at the accelerometers and high speed video will give an insight of the phenomena useful to the mechanical and biomechanical improvement of safety equipment in skiing.
Experimental analysis of ski boots
The micro climate inside the ski boot is very important for safety in skiing since warm, well perfused feet are necessary for a good control of the ski.
In laboratory and field studies the micro climate in the ski boot will be measured. Special measurements will be developed and/or adapted to do measurements of pressure, temperature and humidity. Different ski boot constructions and the influence of the constructions on the geometry of the foot will be tested. At the same time there will be tests with different setups of the inner ski boot and with different materials. Extra physical and climate measurements will be done considering different emphases of for example distribution of humidity/water in different zones of the ski boot or of the dynamic of humidity transport.
By means of this data and tests a prototype for the setup of inner ski boots will be developed and tested in laboratory and field studies.
Simulation of injury mechanism in alpine skiing
The aim of the project is to analyze injury mechanism of the knee involving the anterior cross ligament (ACL) and injuries due to collisions in Alpine skiing. Models of a skier, the knee joint, the skis and the ski-snow interaction are implemented in a computer simulation model to conduct numerical simulations of selected injury mechanism. Especially the loading on the knee joint and its structures are analyzed. By means of parameter studies the effect of the equipment (ski, ski boot, binding) and the skier (physical condition, behaviour) on the loading are investigated and preventive measures are deduced. Additionally protective equipment for the head and knee are tested. Numerical simulations are assisted by experimental studies with dummies, with are well know from crash test in the automotive industry.
During the skiing activities the trauma that involves the mouth are frequently and can do severe wounds. It is known that the balance of the skier is influenced by the trim of the temporo mandibular articulation (postural tonic system) that, if not correct, can introduce postural imbalances increasing the risk of falls. A not correct postural trim than decrease the athletic performance during the sport activities.
Another aspect that influences the comfort and then the safety during the skiing activities is the correct breathing. If the breathing is not natural or is hampered, the skier will be oxygenated in an incorrect manner then the performance of the muscular systems will not be at its maximum.
We want to develop a mouth protector that bringing together these three aspects mentioned above: it performs a protection for the mouth, improving the athletic posture and the breathing.
Opposed on the product on the market today, this mouthguard will be customized by the development of a mould that will be created directly from the stamp of dental arch provided by the doctor dentist. The mouthguard will be formed by injecting the material into the mold. This methodology will create a mouthguard more precise and comfortable.
The development will be divided into three phases:
1)Identifications of suitable materials and mechanical comparison between materials. Impact and tensile tests on samples: tensile properties will be tested in accordance with the normative UNI EN ISO 527-2:1997. Impact properties will be tested in accordance with prEN 15721:2007
2) Develop of a prototype and comparison of the prototype with some commercial protections on the market. During this phase we will develop a moulded prototype that will be tested by the impact on a reproduction of a dental arch equipped with sensors for the measurement of the impact energy absorption. The protection will be equipped by a special bar of rigid material with the purpose of evenly distribute the impact force on the dental arch. The protection will be equipped also of two special thicknesses that will improve the balance and the breath.
We will do some impact test with models equipped with and without these features and we will evaluate the results on the dental arch.
3)Develop of the final model of protector.
This phase will include:
Retention test (prEN 15721:2007)
Impact test on false head and on dummy against barriers
Comfort and balance assessment during real sport activities