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Identification of Nonlinearities in Joints of a Wing Structure

M. S. M., Sani and H., Ouyang (2016) Identification of Nonlinearities in Joints of a Wing Structure. In: MATEC Web of Conferences: International Conference on Structural Nonlinear Dynamics and Diagnosis (CSNDD 2016) , 23–25 May 2016 , Marrakech, Morocco. pp. 1-4., 83 (03006). ISSN 2261-236X

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Nonlinear structural identification is essential in engineering. As new materials are being used and structures become slender and lighter, nonlinear behaviour of structures becomes more important. There have been many studies into the development and application of system identification methods for structural nonlinearity based on changes in natural frequencies, mode shapes and damping ratios. A great challenge is to identify nonlinearity in large structural systems. Much work has been undertaken in the development of nonlinear system identification methods (e.g. Hilbert Transform, NARMAX, and Proper Orthogonal Decomposition), however, it is arguable that most of these methods are cumbersome when applied to realistic large structures that contain mostly linear modes with some local nonlinearity (e.g. aircraft engine pylon attachment to a wing). In this paper, a multi-shaker force appropriation method is developed to determine the underlying linear and nonlinear structural properties through the use of the measurement and generation of restoring force surfaces. One undamped mode is excited in each multi-shaker test. Essentially, this technique is a derivative of the restoring surface method and involves a non-linear curve fitting performed in modal space. A reduced finite element model is established and its effectiveness in revealing the nonlinear characteristics of the system is discussed. The method is demonstrated through both numerical simulations and experiments on a simple jointed laboratory structure with seeded faults, which represents an engine pylon structure that consists of a rectangular wing with two stores suspended underneath.

Item Type: Conference or Workshop Item (Lecture)
Uncontrolled Keywords: Wing Structure; Nonlinearity
Subjects: T Technology > TJ Mechanical engineering and machinery
Faculty/Division: Centre of Excellence: Automotive Engineering Centre
Faculty of Mechanical Engineering
Depositing User: Dr. Mohd Shahrir Mohd Sani
Date Deposited: 30 Nov 2016 07:07
Last Modified: 22 Jan 2018 07:57
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