Structural Health Monitoring Of Composite Structures Based On Impact Force Identification

Paper number

IAC-07-C2.5.01

Author

Prof. Hisao Fukunaga, Tohoku University, Japan

Coauthor

Prof. Ning Hu, Tohoku University, Japan

Year

2007

Abstract

External impact events give severe damage to composite structures and may cause a catastrophic fracture of structures. Modern techniques of structural health monitoring are a possible resort to insure the safety of composite structures. The identification of the external impact forces is important for structural health monitoring and has been investigated by many researchers. For examples, the authors proposed a technique to identify the location and history of impact forces based on a finite element method. However, it is difficult to construct a precise analytical model on complicated structures such as spacecraft wings and fuselages.Then it is important to develop the impact force identification method using only experimental data without resorting to an analytical model.
The present paper discusses a feasibility of a health monitoring method of CFRP structures based on impact force identification. Especially this paper examines an experimental identification method of impact forces acting on CFRP structures. The experimental relation between force histories and strain responses, i.e., transfer matrix, is first determined by using measured force histories and the corresponding strain responses. The location and history of impact force is identified based on this relation. The validity of the present identification method has been verified through an impact test of CFRP stiffened panel with an impulse hammer. 
In the identification method stated above, we assume that there is no damage in structures, and we use a transfer matrix of a healthy structure. The present method can also be applied to the impact force identification of CFRP plate involving impact damages such as delamination. We consider the impact force identification in a drop-weight impact test where the impact damage is induced within the laminate. It is shown that the force history can be identified using a transfer matrix of a healthy structure when the impact damage is not so severe. Then we can estimate the damage extent from the information of identified results of impact force.

Abstract document

IAC-07-C2.5.01.pdf

Manuscript document

IAC-07-C2.5.01.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.