REPORT: Investigation on Curvilinear Anisotropy via Isogeometric Analysis (IGA)

TL;DR

This paper introduces a NURBS-based Isogeometric Analysis framework for simulating curvilinear fiber composites, demonstrating improved efficiency and accuracy over traditional FEA, and optimizing fiber paths to significantly reduce stress concentrations.

Contribution

The study develops and validates a NURBS-based IGA method for complex anisotropic composites, outperforming FEA in efficiency and enabling effective fiber path optimization.

Findings

NURBS-based IGA outperforms FEA in efficiency and accuracy.

Curvilinear anisotropy reduces stress concentration by up to 82%.

Optimized fiber paths improve composite performance without stiffness loss.

Abstract

The advent of multi-material additive manufacturing and automated composite manufacturing has enabled the design of structures featuring complex curvilinear anisotropy. To take advantage of the new design space, efficient computational approaches are quintessential. In this study, we explored a new NURBS-based Isogeometric Analysis (IGA) framework for the simulation of curvilinear fiber composites and we compared it to standard Finite Element Analysis (FEA). A plate featuring a semi-circular notch under tensile loading with different fiber configurations served as a case study. We showed that, thanks to the exact geometric representation and the enriched continuity between elements, NURBS-based IGA outperforms classical FEA in terms of computational efficiency, time-consumption, and estimation quality of field variables for same number of degrees-of-freedom. To further demonstrate the use of the IGA framework, we performed optimization studies aimed at identifying the fiber paths minimizing stress concentration and Tsai-Wu failure index. The model showed that curvilinear anisotropy can be effectively harnessed to reduce the stress concentration of up to 82 % compared to unidirectional composites without affecting the overall plate stiffness significantly.