Title: The use of pseudo-inverse methods in reconstructing loads on a missile structure

Authors: Rajeev Vishwakarma; Dennis Turner; Andrew Lewis; Yongkang Chen; Yigeng Xu

Addresses: School of Engineering and Technology, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, UK. ' Mechanical Analysis Group, MBDA, Stevenage, Hertfordshire, SG1 2DA, UK. ' School of Engineering and Technology, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, UK. ' School of Engineering and Technology, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, UK. ' School of Engineering and Technology, University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, UK

Abstract: A missile during air carriage is subjected to high vibratory forces. These forces consequently impose high levels of stress on the attachment points to the aircraft. A repetitive application of stress causes fatigue. However, since the vibratory forces cannot be measured directly at the interface, an inverse method utilising missile accelerometer data has been used to determine the forces. This paper presents two frequency domain techniques of reconstructing loads. Both techniques utilise the Moore-Penrose pseudo-inverse method, although the second procedure incorporating a normal modes analysis is perhaps better suited for embedding within a health and usage monitoring system (HUMS). Both techniques enable discrete dynamic loads, which are applied to a finite element model in the time domain, to be successfully reconstructed. Consequently, by identifying forces on a missile structure successfully, the presented techniques enable a better structural integrity assessment to be undertaken.

Keywords: inverse methods; load reconstruction; aerospace structures; Moore-Penrose pseudo inverse; health monitoring; usage monitoring; missile structure; stress; fatigue; vibratory forces; vibration; missile accelerometer data; finite element method; FEM; modelling; structural integrity assessment; attachment points.

DOI: 10.1504/IJMIC.2012.049690

International Journal of Modelling, Identification and Control, 2012 Vol.17 No.3, pp.242 - 250

Published online: 17 Dec 2014 *

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