Experimental Modal Analysis Of Large Fuselage Panel For Composite Structure: Contact And Non-Contact Measurement Marcin Luczak 1 , Antonio Vecchio 1 , Emiliano Mucchi 2 and Elena Pierro 3 1 LMS International, Interleuvenlaan 68, B-3001 Leuven, Belgium email: marcin.luczak@lmsintl.com email: antonio.vecchio@lms.be 2 EnDIF-Engineering Department in Ferrara, Universit degli Studi di Ferrara Via Saragat 1, I-44100 Ferrara, Italy email: emiliano.mucchi@unife.it 3 DIMeG-Politecnico di Bari v.le Japigia 182, 70126 Bari, Italy email: e.pierro@poliba.it Abstract This paper presents the results of a research activity aimed at assessing the impact of several excitation and measure techniques used on the composite structure on the modal model parameters variability. To this aim, an intensive test campaign is carried out on an aircraft fuselage panel made of composite material. Contact and non-contact 1D and contact 3D measurements were performed. Modal models are extracted from dynamic test data collected during a test campaign on a composite material fuselage panel. Assessment of the excitation method and the measurement technique and directions on the modal model parameters is being made. 1 INTRODUCTION Problems presented in this paper are the results of a first part of the UNVICO-2 research project oriented for testing, modelling and updating the non-deterministic FE models of the composite material structures [1]. Competitive market forces manufacturers of the composite structures to reduce the test time and depend on much less time and cost consuming numerical simulations. However computational models have to be validated against the experimental models to prove their reliability. Experimental Modal Analysis (EMA) technique is established tool for the identification of dynamic properties of structures [2- 4]. Modal models can be applied in many ways, and one of them is Finite Element Method (FEM) model updating procedure [5-9]. The test data is used against the numerical simulation results to correct the parameters of the FE model as such it yields the results close to those from measurement. Second area of application of EMA could be Structural Health Monitoring (SHM) based on the observation of a value of modal parameter [10-13]. For these two applications a reliable modal test data is of vital importance. However test data is a subject of variability. Many factors such as production process, wear, material imperfections, environmental conditions on one hand and experimental setup on the other lead to scatter of a measurement data of nominally identical structures. Test data variabilities are subject of extensive studies in many research centres [14-18]. Variabilities of the test data come from number of sources. Internal source is non-repetitive production process causing that two nominally identical units have geometric and material properties within production tolerances. Example of the external source of test data variability is an environmental parameter change [19-22]. External source of test data variability could be also test setup [23, 24]. Within test setups there are three main components of the variability of 1729