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Virtual Autoclave for evaluation of right boundary conditions for process induced deformation analysis of large composite structures
C. Brauner, A., Miene, S. Ochoa, A.S. Herrmann, International Conference on Manufacturing of Advanced Composites ICMAC, 24-25 June 2015, Bristol, UK

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The objective of this study is to present a virtual process chain for a manufacturing process of
composite structures which represents all physical effects leading to critical quality aspects such as
process-induced deformations and stresses. To determination of process induced deformations and
residual stresses it is necessary to examine the right boundary conditions. In terms of large composite
structures like panels e.t.c. which are manufactured using a autoclave processes the curing process
will determine the final properties of the composite. In opposite to metallic material the composite
properties are totally dependent on this step. Inside the autoclave the part is heated by hot gases
which are forced to flow over the part surface. This can be classified as heating by forced convection
and is dependent on the flow velocity and the direction of motion. In the following study a semi
analytical method is developed to compute the right temperature boundary conditions for composite
parts cured in a autoclave dependent on the parameters of the autoclave. Complex CFD calculations
are used to evaluate the complex flow field in the empty autoclave. This flow field is used as initial
velocity to compute the flow around a plate using potential flow theory. Using the part dependent
velocity the heat transfer coefficient is determined using analytical expressions and used in an explicit
finite difference schema to calculate the heat flow inside the part. The result of the virtual autoclave is
a fast method to analyse the temperature conditions. These time temperature functions are used by a
mapping method in a FE warpage analysis using a viscoelastic cure dependent approach which was
developed previously.
The virtual autoclave method and the model for warpage analysis are used on the application of a
stiffened composite panel.

FP7 
The Seventh Framework Programme (FP7) bundles all research-related EU initiatives together under a common roof playing a crucial role in reaching the goals of growth, competitiveness and employment.

 

 

 

 

 

   

 

 

Project partners
 
DEUTSCHES ZENTRUM FUER LUFT-UND RAUMFAHRT E.V.  
AIRBORNE TECHNOLOGY CENTER B.V.  
BOMBARDIER AEROSPACE, BELFAST  
DASSAULT SYSTEMES SA  
FASERINSTITUT BREMEN EV  
HUTCHINSON SA  
LOOP TECHNOLOGY LIMITED  
STICHTING NATIONAAL LUCHT- EN RUIMTEVAARTLABORATORIUM  
POLYWORX BV  
SAMTECH SA  
SYNTHESITES INNOVATIVE TECHNOLOGIES LTD