Structure borne sound investigation of a light weight floor with the help of Markov chain walking patterns

Each person has a very individual way of walking, though persons having the same sex and the same height, weight and age are likely to have similarities in the angle of the feet and the length of the stride. To simulate this, a number of Markov chains, that describe the stride, were created from experiments with 150 different males. The Markov chains were then used to create an artificial person for simulations, with a height of between 181-185 cm and a weight of 80 kg, which was to walk over the length of the floor. Each stride contained both heel and toe excitation defined based on the mean value of each concurrent stride. The floor in the simulation, created with the help of FEM, is a lightweight floor built out of wooden beams and particle board on top. This system was chosen due to its low weight per square meter compared to the weight of the walking person which therefore can be set in motion more easily. From the FEM simulation the velocity of all points of the floor was extracted. The velocity was then used to calculate the radiated sound pressure from the floor to different points on the floor below. The radiation from the different points of the floor will be presented graphically for 3 different measurement points.