VAPAS, Powerful Modeling of Composite Plates and Shells
VAPAS Homepage
Introduction
Variational Asymptotical Plate and Shell
Analysis (VAPAS) can be used to
model composite plates and shells to calculate the generalized
two-dimensional
stiffness matrices as inputs for two-dimensional plate/shell analysis
and recover the 3-D displacement/strain/stress
distributions through the thickness. The main features are:
-
VAPAS applies Variational Asymptotic Method (VAM) as its mathematical
foundation to rigorously decouple the original nonlinear three-dimensional
elasticity problem into a one-dimensional, linear, through-the-thickness
analysis over
the normal line and
a two-dimensional, nonlinear, plate/shell analysis over the reference
surface
- VAPAS uses 3-D material constants as input. They are
not laminate stiffnesses or plane-stress-reduced stiffness as used in
many other models
- VAPAS is a standard 1- D Finite Element code and it is fully
modularized and can be easily integrated into
a CAD/CAM software, or any standard commercial codes for plate/shell
analysis
- The asymptotically correct through-the-thickness and
geometrically- exact
shell/plate analyses come from a common framework
-
VAPAS not only calculates the famous A, B, D matrices (corresponding to the classical lamination theory)
but also calculates the transverse shear stiffness matrix for Reissner-Mindlin type plate/shell theory.
Traditionally, the transverse shear stiffnesses are obtained using shear correct factors which are only valid for isotropic
plates and shells.
-
VAPAS can give a very accurate recovery of the 3-D displacement, strain and stress distributions through the thickness based on a
Reissner-Mindlin type 2-D solver. This type of results is very important for detailed analysis.
-
VAPAS can model a general composite plate/shell under severe operating environment
(such as significant different temperature and
moisture from the manufacturing conditions).
-
VAPAS can model a general piezoelectric composite plate/shell to predict the actuation effect due to the fact that
part of
the structure is made with smart material.
VAPAS Manual
Typical Examples
All the users are encouraged to post their problems solved by VAPAS.
Please
document the detailed specification of your problem and the result you
obtained. Please use MS Word or LaTex and send a copy to
Dr. Wenbin Yu.
VABS Frequently Asked Questions
To streamline the Tech support for the code and theory, a forum is established so that VAPAS 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. VAPAS 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. Your request
will be answered as soon as possible.
Please notice that redistribution of VAPAS is not
allowed. The code is copyrighted and all rights
reserved to the author. Please redirect others who want to try VAPAS to
Prof. Wenbin Yu at Utah State University
for permission.
Main References
-
Yu, W.; Hodges, D. H.; and Volovoi, V. V.: "Asymptotic
Construction
of Reissner-like Composite Plate Theory with Accurate Strain
Recovery," International
Journal of Solids and Structures, vol. 39, no. 20, 2002, pp. 5185 - 5203.
-
Yu, W.; Hodges, D. H.; and Volovoi, V. V.: ""Asymptotic Generalization
of Reissner-Mindlin Theory: Accurate Three-Dimensional Recovery for Composite Shells,"
Computer Methods in Applied Mechanics and Engineering,
vol. 191, no. 44, 2002, pp. 4971-5112.
-
Yu, W.; Hodges, D. H.; and Volovoi, V. V.: "Asymptotically
Accurate 3-D Recovery from Reissner-like Composite Plate Finite
Elements," Computers and Structures, vol. 81, no. 7, 2003, pp. 439-454.
-
Yu, W.; and Hodges, D. H.: "A Geometrically Nonlinear Shear Deformation
Theory for Composite Shells," Journal of Applied Mechanics,
vol. 71, no. 1, 2004, pp. 1-9.
- Yu, W.; and Hodges, D. H.: "A Simple Thermopiezoelastic Model for Composite Plates with Accurate Stress Recovery," Smart Materials and Structures, vol. 13, no. 4, 2004 pp. 926-938
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