Session: 01-06-03: Impact, Fatigue, Damage and Fracture of Composite Structures

Paper Number: 110896

110896 - Peridynamics for Predicting Fatigue Behavior of Modulus Graded Plates 

Composite structural components are used extensively in many diverse fields including military, aerospace, and nuclear due to their ability of adapting to different working conditions and desirable properties of lightweight, strong, and high-temperature resistance. The geometrical or material discontinuities along the interfaces between two distinct materials may lead to local interlaminar stress concentrations. These may cause catastrophic failures although the stress levels are not unduly high. The functionally graded materials (FGMs) enable to minimize the aforementioned stress concentrations by tailoring the material properties continuously in one or more coordinate directions in structures. In order to design FG structures safely, it is very crucial to understand and investigate possible damages under different types of loading conditions. Since structural testing and analysis techniques may be costly, there is a necessity to use improved and accurate computational tools to predict the deformation and stress fields of the FG structures. Numerical simulation of the dynamic crack propagation mechanism in FGMs remains a formidable challenge in computational mechanics because the material properties of FGMs are not symmetric. PeriDynamic (PD) theory is based on integro-differential equations involving time and spatial coordinates. Hence, the equilibrium equations of PD theory are still valid even if the material includes a discontinuity. This feature allows damage initiation and propagation at multiple sites with arbitrary paths inside the material without resorting to special crack growth criteria. Most of the existing PD models require uniform grid spacings in the solution domain with a constant horizon size which may require substantial computational time. This becomes challenging when a dense mesh is required to accurately predict the localized behavior in specific regions of the solution domain [1]. Non-uniform discretization of the solution domain enables the way of reducing the computational cost by allowing for coarse mesh away from the region of crack propagation. However, non-uniform discretization inherently presents a variable horizon size that may lead to the development of ghost-forces and unbalance of the linear and angular momentum. In order to remedy this issue, Ren et al. [2] introduced the concept of dual horizons in PD theory based on a theoretical foundation. It is simple and efficient for non-uniform discretization with a variable horizon and free of ghost forces. This study aims to investigate the influence of material variation in the FG structures on fatigue failure behavior by using the PD theory associated with the dual-horizon concept. By doing so the effects of the stop-holes on the fatigue crack propagation are also considered. The robustness of the present approach is demonstrated by considering FG plates under various boundary and loading conditions as well as material variations.

1- Dorduncu, M., & Madenci, E. (2022). Finite element implementation of ordinary state-based peridynamics with variable horizon. Engineering with Computers, 1-14.

2- Ren, H., Zhuang, X., & Rabczuk, T. (2017). Dual-horizon peridynamics: A stable solution to varying horizons. Computer Methods in Applied Mechanics and Engineering, 318, 762-782.

Presenting Author: Mehmet Dorduncu Erciyes University

Presenting Author Biography: Dr. Mehmet Dorduncu received his Ph.D. in Mechanical Engineering in 2018 from the University of Arizona. He worked as a research assistant in the Department of Aerospace and Mechanical Engineering at the University of Arizona during his Ph.D. studies. He was a visiting student at Nasa Langley Research Center (2016), Hampton, VA, where he conducted research on the development of the Refined Zigzag Theory for predicting failure in composite structures. He is the co-author of Peridynamic Differential Operator for Numerical Analysis (Springer, 2019). His current research is mainly focused on the computational mechanics of materials and structures by using peridynamics, peridynamic differential operator, and finite element method. He is currently an associate professor in the Department of Mechanical Engineering at Erciyes University, Kayseri.

Authors:

Ugur Altay Turkish Aerospace Industries
Mehmet Dorduncu Erciyes University
Suat Kadioglu Middle East Technical University