Detection of debonding in a tile-based thermal protection system via change in stiffness using continuation methods

Thermal protection system is a critical component of a space vehicle and is essential for safe re-entry into the atmosphere. The loss of stiffness in tile-based thermal protection system is an essential mode of damage and has lead to loss of a space vehicle due to excessive aero-dynamic heating during re-entry. The inherent nonlinear nature of the coupling of these tiles with the space vehicle body is well-known. This paper explores this nonlinear coupling and proposes a method based on continuation analysis of the nonlinear model to detect and track this damage. The model used was first proposed by Luo and Hanagud.(1) White, Adams and Jata (2005)(2) used modal analysis to conduct system identification and damage identification on a similar system using method of virtual forces. The resent research presents another approach by utilizing periodic excitations to estimate the presence and degree of damage. Parametric studies are also conducted to study the effect of variations in mass on the detection of change in stiffness using the proposed method.