Development of a Fall-Injury Reducing Flooring System in Geriatric Care : with focus on improving the models used in the biomechanical simulations and evaluating the first test area

Abstract: Fall accidents are the type of accident in Sweden that cause most deaths, the largest number of hospitalizations, and most visits to the emergency room. The elderly are overrepresented in the statistics and with the aging population the costs are increasing. One way of reducing both the personal suffering and the cost to society is to introduce safety flooring. Svein Kleiven and Hans von Holst, professors at the department of Neuronics at KTH, have developed a new type of flooring system aimed to reduce fall related injuries. A first test area has been installed at a care facility and the Technical Research Institute of Sweden, SP, has conducted drop tests on nine different prototypes and found a reduction in impact force between 60- 75 % compared to a wooden flooring. The goals of this Master’s thesis were to conduct material testing to enable a better validation of the finite element (FE) model of the flooring system, validate a FE human body model for a hip impact and conduct fall simulations. The last goal was to evaluate the test area of the flooring system regarding effect on balance and work environment. Tensile tests were conducted to increase the knowledge regarding the different rubber mixtures and surface floors used in prototypes of the flooring system. The human body model had to be modified in regards to material models and anatomy of the hip joint before validated. Two fall simulations were conducted, however with low confidence in the results due to the lack of expected response in the model of the flooring system. A walking test was conducted to investigate if the flooring system affected the balance for the elderly and a questionnaire was created to get subjective ratings from the members of staff at the care facility. The results indicate no clear effect on balance and the subjective ratings shows the importance of also consider the work environment before installing the flooring system. More work remains in developing the flooring system; however this Master’s thesis has increased the understanding of the flooring system, both in regards to material properties and influence on the daily life at the care facility. This thesis also developed a more realistic human model, to be used in further hip impact simulations.