Dynamic stiffness matrix for analysis of modal properties the damaged composite wing

Shams, Shahrokh; Torabi, َA.R.; Fathi Narab, Mahdi

doi:10.22034/jast.2018.145165

Dynamic stiffness matrix for analysis of modal properties the damaged composite wing

Document Type : Original Article

Authors

Shahrokh Shams ¹

َA.R. Torabi ²

Mahdi Fathi Narab ³

¹ Faculty of New Sciences and Technologies

² Fracture Research Laboratory, Faculty of New Science and Technologies, University of Tehran

³ Department of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran

10.22034/jast.2018.145165

Abstract

In this paper, damage in composite wings is introduced, firstly, then using Euler- Bernoulli equations with including flexural and torsional coupling, governing equations on cantilevered composite wing is derived. By applying separation method damaged beam is converted to two interconnected intact beams and using boundary conditions and continues conditions in damage location, the dynamic stiffness matrix is composed and modal analysis of damaged wing is done. Composite type is fiber-reinforced and damage type is edge crack with various locations and depths. Also effects crack depths and locations on modal properties in various fiber angle are examined. Results showed that existence a crack even with small depth in root of large span wing can reduce natural frequencies, seriously.

Keywords

“Cracked wing”

“Dynamic stiffness matrix”

“Modal properties”

“interconnected beam”

20.1001.1.17352134.2018.111.1.2.2

[1] K. Wang, "Vibration Analysis of Cracked Composite Bending-torsion Beams for Damage Diagnosis," Virginia Polytechnic Institute and State University, 2004.

[2] Y. Kim, T. Strganac and A. Kurdila, "Nonlinear flutter of composite plates with damage evolution," in 34th Structures, Structural Dynamics and Materials Conference, 1993.

[3] I. Lottati, "Flutter and Divergence Aeroelastic Characteristics for Composite Forward Swept Cantilevered Wing," AIRCRAFT, pp. 1001-1007, 1985.

[4] L. Meirovitch and L. Silverberg, "Active vibration suppression of a cantilever wing," Journal of Sound and Vibration, vol. 97(3), pp. 489-498, 1984.

[5] J. R. Banerjee, H. Su and C. Jayatunga, "A dynamic stiffness element for free vibration analysis of composite beams and its application to aircraft wings," Computers and Structures, vol. 86, pp. 573-579, 2008.

[6] K. Wang, D. Inman and C. Farrar, "Crack-induced Changes in Divergence and Flutter of Cantilevered Composite Panels," Journal of Structure Health Monitoring , vol. 4(4), pp. 377-392, 2005.

[7] K. Wang, Vibration Analysis of Cracked Composite Bending-torsion Beams for Damage Diagnosis, Blacksburg, Virginia: Virginia Polytechnic Institute and State University, November 29, 2004.

[8] L. Meirovitch and I. Tuzcu, "Unified theory for the dynamics and control of maneuvering flexible aircraft," AIAA, vol. 42, no. 4, p. 714–727, 2004.