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See detailNonlinear Modal Analysis of the SmallSat Spacecraft
Renson, Ludovic ULg; Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg et al

in Proceedings of the European Conference on Spacecraft Structures, Materials & Environmental Testing (2012, March)

Non-linear elements are present in practically all spacecraft structures. When such non-linear effects are important linear modal analysis can no longer be applied. The development of a non-linear ... [more ▼]

Non-linear elements are present in practically all spacecraft structures. When such non-linear effects are important linear modal analysis can no longer be applied. The development of a non-linear analogue of linear modal analysis is therefore an important endeavor. The objective of this paper is to show that nonlinear normal modes (NNMs) represent a useful and practical tool in this context. A full-scale spacecraft structure is considered and is modeled using the finite element method. Its NNMs are computed using advanced numerical algorithms, and the resulting dynamics is then carefully analyzed. Nonlinear phenomena with no linear counterpart including nonlinear modal interactions are also highlighted. [less ▲]

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See detailExperimental identification of a nonlinear space structure
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Kerschen, Gaëtan ULg et al

in Proceedings of the 12th European Conference on Spacecraft Structures, Materials and Environmental Testing (2012, March)

The present paper addresses the experimental identification of a nonlinear space structure, the SmallSat spacecraft developed by EADS-Astrium. The nonlinear component comprises an inertia wheel mounted on ... [more ▼]

The present paper addresses the experimental identification of a nonlinear space structure, the SmallSat spacecraft developed by EADS-Astrium. The nonlinear component comprises an inertia wheel mounted on a support, the motion of which is constrained by eight elastomer plots and mechanical stops. Robust techniques are applied to measured data to detect, characterise and quantify nonlinear behaviour. [less ▲]

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See detailApplication of the restoring force surface method to a real-life spacecraft structure
Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg; Newerla, Alfred

in Proceedings of the International Modal Analysis Conference (IMAC) XXX (2012, January)

Many nonlinear system identification methods have been introduced in the technical literature during the last thirty years. However, few of these methods were applied to real-life structures. In this ... [more ▼]

Many nonlinear system identification methods have been introduced in the technical literature during the last thirty years. However, few of these methods were applied to real-life structures. In this context, the objective of the present paper is to demonstrate that the Restoring Force Surface (RFS) method can provide a reliable identification of a nonlinear spacecraft structure. The nonlinear component comprises an inertia wheel mounted on a support, the motion of which is constrained by eight elastomer plots and mechanical stops. Several adaptations to the RFS method are proposed, which include the elimination of kinematic constraints and the regularization of ill-conditioned inverse problems. The proposed methodology is demonstrated using numerical data. [less ▲]

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See detailNonlinear modal analysis of the SmallSat spacecraft
Renson, Ludovic ULg; Kerschen, Gaëtan ULg; Newerla, Alfred

in Proceedings of the SEM IMAC XXX Conference (2012)

Non-linear elements are present in practically all spacecraft structures. The assumption of a (quasi-)linear structure is nevertheless adequate for structural analyses and design verification purposes in ... [more ▼]

Non-linear elements are present in practically all spacecraft structures. The assumption of a (quasi-)linear structure is nevertheless adequate for structural analyses and design verification purposes in those cases where these structural non-linearities are relatively weak or not substantially activated by the mechanical environments encountered during the launch or during ground testing. However, when significant non-linear effects in spacecraft structures are no longer negligible then linear modal analysis will not be able to handle non-linear dynamical phenomena in an adequate manner: the development of a non-linear analogue of linear modal analysis becomes an urgent and important issue. The objective of this paper is to show that nonlinear normal modes (NNMs) represent a useful and practical tool in this context. A full-scale spacecraft structure is considered and is modeled using the finite element method. Its NNMs are computed using advanced numerical algorithms, and the resulting dynamics is then carefully analyzed. Nonlinear phenomena with no linear counterpart including nonlinear modal interactions are also highlighted. [less ▲]

Detailed reference viewed: 54 (15 ULg)