Application of Variational Asymptotic Method for Structural Analysis of Fan Rotor Blades in Boundary Layer Ingesting Flow Field

An error is introduced by the conventional approach of applying beam theory in the presence of interiorly applied loads. This error arises from neglecting the influence of the precise distribution of surface tractions and body forces on the warping displacements. This paper intends to show that beam theory is capable of accounting for this influence on warping and accomplishes this by the variational asymptotic method. Correlations between elasticity solutions and beam solutions provide not only validations of beam solutions, but also illustrate the resulting errors from the conventional approach. Correlations are provided here for an isotropic parallelepiped undergoing pure extensional deformations and for an isotropic elliptic cylinder undergoing pure torsional deformations.

Download Full-text

Prediction of Mechanical Properties of Microcellular Plastics Using the Variational Asymptotic Method for Unit Cell Homogenization (VAMUCH) Method

Volume 1: Processing ◽

10.1115/msec2013-1254 ◽

2013 ◽

Author(s):

Emily Yu ◽

Lih-Sheng Turng

Keyword(s):

Mechanical Properties ◽

Asymptotic Method ◽

Thermoplastic Polyurethane ◽

Three Dimensional ◽

Unit Cell ◽

Element Analysis ◽

Microcellular Plastics ◽

Variational Asymptotic ◽

Variational Asymptotic Method ◽

Injection Molded

This work presents the application of the micromechanical variational asymptotic method for unit cell homogenization (VAMUCH) with a three-dimensional unit cell (UC) structure and a coupled, macroscale finite element analysis for analyzing and predicting the effective elastic properties of microcellular injection molded plastics. A series of injection molded plastic samples — which included polylactic acid (PLA), polypropylene (PP), polystyrene (PS), and thermoplastic polyurethane (TPU) — with microcellular foamed structures were produced and their mechanical properties were compared with predicted values. The results showed that for most material samples, the numerical prediction was in fairly good agreement with experimental results, which demonstrates the applicability and reliability of VAMUCH in analyzing the mechanical properties of porous materials. The study also found that material characteristics such as brittleness or ductility could influence the predicted results and that the VAMUCH prediction could be improved when the UC structure was more representative of the real composition.

Download Full-text

A Multiphysics Micromechanics Model of Smart Materials Using the Variational Asymptotic Method

Smart Materials, Adaptive Structures and Intelligent Systems, Volume 1 ◽

10.1115/smasis2008-366 ◽

2008 ◽

Author(s):

Tian Tang ◽

Wenbin Yu

Keyword(s):

Asymptotic Method ◽

Smart Materials ◽

Effective Properties ◽

Primary Objective ◽

Local Fields ◽

New Model ◽

Micromechanics Model ◽

Variational Asymptotic ◽

Variational Asymptotic Method ◽

Micromechanics Modeling

The primary objective of the present paper is to develop a micromechanics model for the prediction of the effective properties and the distribution of local fields of smart materials which are responsive to fully coupled electric, magnetic, thermal and mechanical fields. This work is based on the framework of the variational asymptotic method for unit cell homogenization (VAMUCH), a recently developed micromechanics modeling scheme. For practicle use of this theory, we implement this new model using the finite element method into the computer program VAMUCH. For validation, several examples will be presented in the full paper to compare with existing models and demonstrate the application and advantages of the new model.

Download Full-text