VAMUCH, a General-Purpose Micromechanics Analysis Code for Heterogeneous Materials

VAMUCH

A General-Purpose Micromechanics Code

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Uniqueness of VAMUCH

Target Applications

Homogenization of heterogeneous materials
Multiscale modeling of composite structures
Layered composites/bindary composites
Fiber Reinforced Materials
Particle Reinforced Materials
General-purpose micromechanics analysis
Effective properties including elastic properties, coefficients of thermal expansion, specific heats, thermal conductivities

Introduction

Variational Asymptotical Method for Unit Cell Homogenization (VAMUCH) is a finite element-based, general-purpose micromechanics code to perform homogenization of heterogeneous materials based on the variational asymptotic method. It can be used to calculate the effective material properties for arbitrary heterogeneous materials with arbitrary microstructure providing a unit cell can be identified. The heterogeneous material could compose of arbitrary number of constituents having full anisotropy. VAMUCH calculates the complete set of material properties within in one analysis. If needed, VAMUCH can also recover the displacement/strain/stress fields within the microstructure. In comparison to the state-of-the-art tools for predicting properties of heterogenous materials, VAMUCH has the following unique features:

VAMUCH adopts variational asymptotic method as its mathematical foundation. Ad hoc assumptions prevalent in other methods are avoided by taking advantage of the fact that the size of unit cell is much smaller than the macroscopic dimension of structure. VAMUCH achieves the same accuracy (best available accuracy) as mathematical homogenization theories without even assuming periodic boundary conditions.

VAMUCH handles 1D/2D/3D unit cells uniformly.

VAMUCH calculates the complete set of effective material properties simultaneously within one analysis without applying any load. It is fundamentally different from common practice to extract various material properties from multiple analyses of the unit cell under different load conditions.

VAMUCH calculates effective properties and local fields directly with the same accuracy as the fluctuation functions. No postprocessing calculations such as averaging stresses and averaging strains are needed.

VAMUCH uniquely determines the local fluctuation functions and local displacement fields.

The dimensionality of the problem is determined by that of the periodicity of the unit cell. A complete 6x6 effective material matrix which is needed for 3D macroscopic analysis can be obtained even from a 1D analysis of 1D unit cells.

VAMUCH Documentation

Typical Examples

All the users are encouraged to post their problems solved by VAMUCH. Please document the detailed specification of the problem and the results. Please use MS Word or LaTex and send a copy to Dr. Wenbin Yu. You can download the input files for most of cases from here.

VAMUCH Frequently Asked Questions

To streamline the Tech support for the code and theory, a forum is established so that VAMUCH users can help answer each other's questions and same/similar questions will not be asked more than once. I will constantly visit the forum to address questions not answered or answered wrong. If you have an urgent question need to be resolved sooner, please post the question on the forum first, then send me an email to let me know the urgency. Please click here to register. VAMUCH related messages should be posted in my Research Forum.

Want to Try?

Please send the request to Prof. Wenbin Yu at Utah State University with a brief introduction of yourself (including your name, organization, highest degree obtained or seeking) and a short motivation of wanting to have this program and which operating system (such as win32, Mac OS, linux and etc.) you are using. Your request will be answered as soon as possible. Please notice that redistribution of VAMUCH is not allowed. The code is copyrighted by Wenbin Yu and all rights reserved.

Main References

Yu, W.: "A Variational-Asymptotic Cell Method for Periodically Heterogeneous Materials," Proceedings of the 2005 ASME International Mechanical Engineering Congress and Exposition, Orlando, Florida, Nov. 5-11, 2005.
Yu, W. and Tang, T.: "Variational Asymptotic Method for Unit Cell Homogenization of Periodically Heterogeneous Materials," International Journal of Solids and Structures, vol. 44, 2007, pp. 3738-3755."
Yu, W. and Tang, T.: "Asymptotical Construction of a Micromechanics Model for Periodically Heterogeneous Anisotropic Materials," Proceedings of the 47th Structures, Structural Dynamics, and Materials Conference, Newport, Rhode Island, May 1-4, 2006.
Yu, W. and Tang, T.: "A New Micromechanics Model for Predicting Thermal Properties of Heterogeneous Materials," Proceedings of the 2006 ASME International Mechanical Engineer-ing Congress and Exposition , Chicago, Illinois, Nov. 5-10, 2006.
Yu, W. and Tang, T.: "A New Micromechanics Model of Heterogeneous Materials," Proceedings of the 17th Army Solid Mechanics Symposium, Baltimore, Maryland, Apr. 2-5, 2007 (Abstract).
Williams, T. O.; Yu, W.; Aboudi, J.; and Bednarcyk, B. A.: "A Critical Evaluation of the Predictive Capabilities of Various Advanced Micromechanics Models," Proceedings of the 48th Structures, Structural Dynamics, and Materials Conference, Waikiki, Hawaii, Apr. 23-26, 2007.
Tang, T. and Yu, W.: "A New Micromechanics Model for Predicting Effective Thermal Conductivity of Heterogeneous Materials," Proceedings of the 48th Structures, Structural Dynamics, and Materials Conference, Waikiki, Hawaii, Apr. 23-26, 2007.

Acknowledgement

Development of VAMUCH was initiated by support of the National Science Foundation under Grant DMI-0522908. Later it was supported by the State of Utah Community/University Research Initiative Grant. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsement, either expressed or implied, of the funding agencies.

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