Dynamic behaviour of floor systems in accommodation areas

Abstract

Vibration can cause structural damage and negative impacts on human health in accommodation areas. Thus, engineers have to design structures avoiding resonance phenomena which occurs forced frequency equals to natural frequency. Therefore to avoid structural damage and negative impacts on the human health, natural frequencies of structures have to be known by engineers.

Floor system is entire system of components between supporting beams or girders. In shipbuilding industry, accommodation floor systems normally consists at least two different layers which are steel and material based concrete. Developing materials science and industry lead us to have more and better floor options. In order to avoid noise and vibration problems, engineers have better solutions. In contrast these floor types have complex structures. Therefore measuring and analysing the dynamic behaviour of floor structures are essential matters for engineers.

In this study, dynamic behaviour of typical design solutions as applied in accommodation areas was evaluated. Local vibration analyses were performed for selected configurations. Using finite element method the different layers of floor systems were modelled as composite elements and volume elements. The effect of added masses was analysed. The main focus of this study is local vibration analysis of floor systems in accommodation areas. Finite element method is based on modal analysis for local vibration analyses.

All materials and parameters were selected according to floor applications in accommodation areas. These data can be used for any further calculations. For the effect of added masses, input values were selected according to previous local vibration analyses. Definition of typical dimensions and configurations were considered according to a real ship’s accommodation floor design plans. Plate, stiffener and panel vibrations were calculated with special focus on varying floor systems. All floor systems which have different layers are modelled using ANSYS structural model elements. Finite element analyses conducted include modal analyses and harmonic analyses using ANSYS Mechanical APDL software package

The thesis was developed as application of finite element method. The accuracy of results was confirmed by analytical formulae. More complex floor systems and the actual parts of accommodation areas analyses can be future studies.