Session: 02-06-01: Structural Dynamics and Control of Morphing Wing and Smart Structures

Paper Number: 106775

106775 - A Novel Method for Estimating Deformation and Stress Fields in Layered Composites Induced by Internal Defects and External Environmental Loads 

Deformation and stress fields in multilayered composites induced by either internal defects or external environmental loads are important for safe design. In this paper, we introduce a general and powerful mathematical approach to calculate the induced deformation and stress fields. The defects can be dislocation loops, lattice dislocations or misfit dislocations. The external environmental loads can be a general force vector with three independent components. The boundary-value problem (BVP), both static and time-harmonic associated with the layered composites, is categorized into two:

For the involved materials which possess axis-symmetry, we will handle them via the recently introduced Fourier-Bessel series system of vector functions L, M, and N. Based on this system, one can pre-calculate the discrete Love numbers, the Green’s functions, and finally the general response of the composites under internal and external sources. It should be pointed out that this unique mathematical vector function system is closely connected to the deformation and wave modes: While the LM-type solution represents the dilatational deformation, and P-, SV-, and Rayleigh-waves, the N-type solution is for the torsional deformation, and SH- and Love-waves.   

When the materials involved are general anisotropy, the mathematically elegant and computationally powerful Stroh formalism will be utilized. In terms of the Stroh formalism, the BVP in the transformed domain is reduced to a simple eigenvalue problem which can be easily solved by any standard method.

Furthermore, in both sub-problems, the unconditionally stable layer matrix, called dual-variable and position method, will be employed. It has been shown that this layer matrix is superior to any existing layer matrices, in terms computational time, flexibility and stability.   

Presenting Author: Ernian Pan National Yang Ming Chiao Tung University

Presenting Author Biography: Ernian Pan obtained his BS and MS degrees from Lanzhou University and Beijing University, respectively, and his PhD from University of Colorado at Boulder. He joined the National Yang Ming Chiao Tung University in Taiwan in January 2022 as a Chair Professor after 18 years with the University of Akron in Ohio. His teaching and research are in continuum/computational methods/mechanics with applications in modern engineering and Earth science problems including pavement/earth deformation due to surface loading and internal source, mechanical and electronic properties of nanoscale quantum heterostructures, and mangetoelectric effect in multiferroic composites. He has a great passion on Green’s functions, particularly those in anisotropic and layered systems. He has published over 370 peer-reviewed journal articles, designed a couple of software products, coauthored a book in 2015 with Prof. W. Q. Chen, titled Static Green's Functions in Anisotropic Media by Cambridge University Press, and written a review in 2019 Rep. Prog. Phys. titled “Green’s functions for geophysics: a review”.

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