A valid inhomogeneous cell-based smoothed finite element model for the transient characteristics of functionality graded magneto-electro-elastic structures

Development of smart devices including actuators and sensors attracted significant attention by scientists for various applications. Interestingly, the design and development of smart devices require intelligent materials with distinct characteristics and properties, specifically, functionally graded magneto-electro-elastic (FGMEE) materials have been identified as a promising group of intelligent materials. As such, high-performance can be realized through better understanding of both smart devices and intelligent materials. Unfortunately, the transient response of functionally graded magneto-electro-elastic materials have not been fully explored.

Presently, the use of computers has enabled the development of several models for the analysis of various properties of materials. To date, the finite element model has been particularly of significant importance in solving numerous and complex problems. However, due to several limitations like overly-stiff that results in inaccurate values, smoothed finite element models have been developed. On the other hand, strain smoothing technique has been used to derive other smoothed finite element models like edge-based and cell-based models. The latter has been preferred because of its user-friendly interface. Despite the remarkable achievements using these models, cell-based smoothed finite element model does not allow transient response analysis of functionally graded magneto-electro-elastic structures.

To this note, Jilin University researchers: Dr. Liming Zhou, Shuhui Ren (MSc candidate), Changyi Liu (PhD candidate) and Dr. Zhichao Ma from the School of Mechanical and Aerospace Engineering introduced inhomogeneous cell-based smoothed finite element model (ICS-FEM) into the multi-physics coupling problems and analyzed the transient responses of functionally graded magneto-electro-elastic structures. Additionally, a modified Newmark technique was also developed alongside this model. They purposed to eliminate the problems associated with finite element method, including sensitive to mesh distortion and overly-stiff, etc. The research work is published in the journal, Composite Structures.

In brief, the research team initiated their work by cross-examining the past studies to determine the functionality trends of both edge-based and cell-based smoothed finite element model as well as other models resulting from combination of the aforementioned ones. Next, the method was used to obtain the stiffness and mass matrices that were also used in analyzing the transient response of these materials. Eventually, the feasibility of the presented method was validated by using numerical examples under different boundary conditions and mechanical loads, and the results compared to that of the finite element model.

The authors observed good convergence and high accuracy in the ICS-FEM as compared to the finite element model. This was attributed to the elimination of the overly-stiff problem. Consequently, it also proved suitable for distorted mesh calculations for a shorter time duration and less nodes.

In summary, Jilin University scientists successfully presented a valid tool for efficient analysis of multi-physics coupling problems, including calculation of transient response in complex functionally graded magneto-electro-elastic structures. Being a user-friendly especially in defining the software subroutines, the method will advance the design and development of intelligent materials to be used in smart devices.