Applying force panels for wave impact measurements

Measurements of wave impacts are important in several fields. Wave impacts on a ship model can be measured using force panels that are mounted on the model. These force panels are a combination of a standard force transducer with a small impact plate on top of the force transducer. The static behaviour of the force panel can be easily determined by a static calibration. However, knowledge of the dynamic behaviour of the force panel is essential for the understanding of the measurement of highly dynamic wave impacts with these force panels. This paper presents a methodology to determine the dynamic behaviour of a force panel. This approach is not a dynamic calibration but a characterisation of the dynamic behaviour of the force panel. The characterisation is based on modal analysis using an instrumented impact hammer. Relevant theoretical background for the method is briefly discussed. All individual steps in the characterisation process such as set-up, measurement and analysis are clarified and discussed. The presented method is used for qualification of force panels in a calibration laboratory and for verification of the force panels that are installed on a model. Features of the application of force panels measuring actual wave impacts on model scale are discussed.