Three-node, Inverse Shell Element, iMIN3

Structural health management systems, which by way of real-time monitoring help mitigate accidents due to structural failures, will become integral technologies of the next-generation aerospace vehicles. Advanced sensor arrays and signal processing technologies are utilized to provide optimally distributed in-situ sensor information related to the states of strain, temperature, and aerodynamic pressure. To process the massive quantities of measured data and to infer physically admissible structural behavior requires robust and computationally efficient physics-based algorithms.

The inverse problem of real-time reconstruction of full-field structural displacements, strains, and stresses is addressed using an inverse finite element method based on shear deformable shell finite element technology. Utilizing surface strain measurements from strain sensors mounted on load-carrying structural components, the methodology enables accurate computations of the three-dimensional displacement field for a general built-up shell structure undergoing multi-axial deformations. The strain and stress computations are then carried out at the element level using strain-displacement and constitutive relations. This high fidelity computational technology is essential for providing feedback to the actuation and control systems of the next generation of aerospace vehicles, and for assessing real-time internal loads and structural integrity.