Session: 28-01: Reduced-Order Modeling of bladed disks

Paper Number: 152679

Parallel Computation of the Nonlinear Forced Response of a Bladed Disk With Friction Contacts Using the FETI Method 

The size of the Finite Element (FE) models used for turbomachinery applications is nowadays rapidly growing to take into account the whole engine dynamics and the complex dynamic interactions between sub-assemblies, which are connected by means of removable friction contacts. In this context, the aim of this paper is the introduction of a parallel harmonic balance method (HBM) for the nonlinear forced response analysis of bladed disks with localized contact nonlinearities.

The proposed technique is based on the finite element tearing and interconnecting (FETI) method, originally introduced by C. Farhat and F. X. Roux in 1991 for the solution of static linear problems. The main idea behind this technique is the decomposition of the FE model into several domains coupled by interface forces that are mathematically modelled using the  Lagrange multipliers method.

The adoption of this approach for the computation of the nonlinear forced response of turbomachinery components, overcomes the limitations and hypotheses introduced with the use of reduction techniques to obtain Reduced Order Models (ROM), making possible the study of the entire model. Furthermore, the reduction pre- and post-processing steps are eliminated, which are typically highly demanding in terms of memory allocation and computationally resources.

From an industrial user perspective, this approach simplifies the analysis procedure and the study of phenomena involving the full bladed disk. On the other hand, the development of nonlinear solver for high performance computing (HPC), represents a challenge for the community of software developer. This is due to the need to introduce strategies and methods aimed at minimizing the number of global operations that involve the interfaces between adjacent domains, which represent the main bottleneck in the parallel programming. A comprehensive description of the implemented method and a validation on a full bladed disk is provided in the paper.

 

Presenting Author: Andrea Saponaro Politecnico di Torino

Presenting Author Biography: Andrea Saponaro is a Ph.D student at the Politecnico di Torino. He started its university career in 2018 at the Politecnico di Torino, obtaining the master degree in Mechanical Engineering in 2023, with a thesis about the development of a linear solver based on the FETI (Finite Element Tearing and Interconnecting) method for the solution of linear problems.

He enrolled the PhD programme in Mechanical Engineering in 2023. Its research consists mainly in the development of nonlinear solvers combining the HBM (Harmonic Balance Method) and the FETI method applied to turbomachinery components involving contact nonlinearities. He has experience with several programming languages focusing on parallel computing.

Authors:

Andrea Saponaro Politecnico di Torino
Giuseppe Battiato Politecnico di Torino
Christian Maria Firrone Politecnico di Torino
Stefano Zucca Politecnico di Torino