Vibration Analyses of a Wooden Floor-Wall Structure- Experimental and Finite Element Studies

Abstract: Changes in the Swedish construction code introduced in 1994 enabled the construction of wooden multistorey buildings. This resulted in an increased need for knowledge about wooden structures in the building industry. The main issue in wooden framed buildings is disturbing vibrations and noise which propagate throughout the construction. It is valuable to be able to predict the behavior of future or existing structures. By creating and analysing calculation models, it is possible to obtain for example eigenfrequencies and the response of a specific load case of a structure. There is much experience in calculations for heavy constructions, but there is a lack of knowledge when it comes to establishing reliable calculation models of lightweight constructions. This Master's dissertation contains experimental and fnite element vibration analyses of a wooden full scale floor-wall structure. The oor structure was built in October 2010 at the Faculty of Engineering at Lund University, LTH. It was excited with harmonic loads from 15 to 400 Hz by a shaker and impulse loads made by hammer strokes, and the response was recorded with accelerometers. The experimental data was processed and evaluated with Matlab to obtain eigenfrequencies and mode shapes. Finite element modeling and analyses were performed with a software called Abaqus. The objective of the project was to compile the eigenfrequencies and mode shapes of the floor structure from the retrieved experimental data and the finite element simulations. The aim was to establish a model that simulates the behavior of the real structure with good resemblance. The analyses were limited to eigenfrequencies below 100 Hz. Measurements were carried out at different stages during the building phase, in order to see the effects on the eigenfrequencies when adding new parts to the structure. Being able to continuously compare the simulated and experimental results made the process of creating a well corresponding finite element model much easier. The final model shows a good resemblance to the real structure in terms of eigenfrequencies and mode shapes for the lower frequencies.