Loading...

Flow Simulation for Vacuum-assisted Resin Transfer Molding in Manufacturing of Composite Structures

Teimouri, Hassan | 2022

98 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55661 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Abedian, Ali
  7. Abstract:
  8. One of the common and efficient methods in the construction of large-scale structures from composites is the Vacuum Assisted Resin Transfer Molding (VARTM) method, which is widely used in the automotive industry, wind turbine blades, warships and pleasure boats, etc. VARTM is one of the liquid molding methods in which one side of the closed mold is replaced with a vacuum bag and the resin flows into the mold only with the help of air pressure (pressure of one atmosphere). One of the main challenges in the vacuum resin molding process is to be aware of the physics governing the flow motion in the porous mold so that the dry spots formed in the mold can be located accordingly. On the other hand, due to the very high cost and time of each process, using the method of trial and error to achieve the physics of resin flow is not a cost-effective method. Therefore, using numerical methods to estimate the resin flow front can be more effective and less costly. There are several finite element methods that can solve the Darcy equation, which represents the physics of flow in a porous medium, for complex shapes, but the most important issue in numerical simulation is the accurate permeability estimate, which depends on various factors such as geometric complexity and fiber compaction. In this study, using the available experimental results for MAWK fiber fabrics, a dry and saturated compaction model is estimated, based on which the effect of fiber compaction on permeability can be considered. In addition, for complex shapes, the effect of torsion and shrinkage of fibers at corner points on permeability has been considered by the Fishnet algorithm, and finally the Mixed-FEM solver has been used to solve the Darcy differential equation on the entire surface. All calculations are programmed to estimate the permeability of the mold, pressure and flux of the resin as well as the flow front in MATLAB software. First, the results of MATLAB code are displayed for a simple rectangular shape and compared with existing experimental results. In addition, to calculate the flow front, an algorithm tailored to the compaction model has been developed. Finally, after validating the MATLAB code for simple shapes, the process simulation is performed for a complex shape that is part of the hull
  9. Keywords:
  10. Permeability ; Finite Difference Method ; Mixed Finite Element Method ; Darcy’s Model ; Vacuum Asisted Resin Transfer Molding (VARTM) ; Compaction Equation ; Shape Compexity ; Flow Front

 Digital Object List

 Bookmark

No TOC