FINITE ELEMENT ANALYSIS (FEA) OF THE JUDO MAT SYSTEMS IN TERMS OF HEAD INJURY SAFETY

Ukemi is the main precaution of the uke against the body injury during a regular judo throw. Since there exists numbers of judo technique which finalizes in different throwing routes, there also exists a number corresponding ukemis almost for each tachi-waza technique. In all type of the ukemis, the common point is to keep the head closer to the chest as much as possible in order to protect it against an undesired shocking impact considering the flexible nature of human neck. It is scientifically reported that, there is a risk of concussion or minor head injury when the force on the head exceeds 10 kN which is equal to 1 tons. This force can easily be reached in a judo throw at the time of the head impact on the tatami resulting from an uncontrolled ukemi. In order to avoid head injuries which may end up with serious results, the material properties and supporting conditions of the judo mat becomes of greater importance. In this study the shock absorption characteristics of judo mats are investigated considering three different support conditions. Finite Element Analysis (FEA) is carried out on judo mat model by using computer software SAP2000. The results show that, providing a timber platform base under the judo mat improves shock absorption capacity of the mat system and therefore decreases the probability of head injury considerably when compared to that of rigid concrete base. The main precaution against the head injury can be stated either to realize a regular ukemi; or to place timber platform under the tatami. In this poster; theoretical background of the problem, details of the FEA modelling and evaluation of the analysis results are presented.