Test method – Upper neck force and moment

Abstract

Crash tests are used to develop and improve vehicle safety and evaluate the injuries caused after a crash. In the neck, injury criteria such as NIC and 𝑁𝑘𝑚 estimate consequences of the crash. In a crash test dummy the upper neck load cell measures the force and the moments between the neck and the head. But in volunteer tests, always non-injurious and at low velocity, is not possible to attach sensors into the neck of the volunteers. Hence the forces and moments in volunteers need to be calculated with data from accelerometers or possible other sensors. The aim of this thesis is to propose a method that can be used to calculate the upper neck forces and moments on human subjects. A review of different methods to calculate the upper neck force and moments has been performed. Advantages and disadvantages have been discussed. Also the physical properties of the human head (mass, moment of inertia, position of the center of gravity and the occipital condyle) are investigated as they are important in the calculation of the upper neck loads. In order to calculate the upper neck force and moment in a crash test carried out with a human subject, the head of the human is considered to be a solid rigid. Therefore, forces and moments in the upper neck are found by applying the dynamics of a solid rigid. As a result of the research, a method is proposed: attach a new sensor in the market (IMT40) in both sides of the projection of the center of gravity in the human head, measure linear and angular acceleration and the angle of the head and finally calculate the neck loads.