RTM simulation with Shaper
At iChrome we are proud to release the alpha version of our Resin Transfer Molding (RTM) solver, namely Shaper RTM.
Shaper RTM, is the result of an Innovate UK co-funded research project between iChrome Ltd, the Univ. of Bristol and Wilson Benesch with the ambition to set new standards for those SMEs that need affordable and reliable RTM manufacturing simulations (more information about the FastRTM project can be found HERE).
Resin Transfer Molding is largely used for the manufacturing of high-quality composite components and it is based around the idea of infusing resin within dry composite fibers. In RTM manufacturing a dry fibrous preform is thus placed in the mold cavity. The resin enters the mold through a number of injection inlets and slowly flows within the mold and the porous fibers.
Shaper RTM, as other well established products on the market such as PamRTM, LIMS and Polyworks, uses the so-called Darcy’s Law to correlate pressure field and resin velocity inside the fibrous domain. Shaper RTM uses a standard FE approach to compute the pressure field within the mold at each analysis step and a dual mesh to define a finite volume mesh to compute the resin front and velocity within the porous fibers.
This post is intended to be a first public and free benchmark of the Shaper RTM solver.
The experimental Test:
The experimental benchmark is a relatively simple square panel of side 38mm. The panel preform is made up of 11 plies of C0475 carbon fibers. Plies are inserted into a 4mm mold, leading to a theoretical injection with fiber volume of 0.44.
The rationale of the test is to assess the resin front at a given time. Hence, Wilson Benesch performed 5 injections, with interruption time of 10 minutes. The resin flow is thus interrupted after 10 minutes, the panels are extracted from the mold and the resin front measured.
Injections were made at room temperature of T=20.5C. Inlet and outlet pressures were measured during the tests with an average differential in pressure of 198885 Pa.
Fig 1: A panel coupon – 10 minutes injection
Measured resin front:
|Panel||R1 (mm)||R2 (mm)|
Numerical Model Set up:
Shaper RTM was used to reproduce the experimental tests. Permeability values have been derived from permeability tests performed at the University of Nottingham, returning the following:
|K11 m^2||K22 m^2|
Resin viscosity at the test temperature of 20.5 C was derived from the data provided by the resin vendor, being of 0.374 Pa*s.
Fig 2: Finite Element Mesh
This section briefly reports the obtained numerical results. Shaper RTM solver required about 4 minutes of running time to complete the analysis, i.e. to simulate the complete filling of the panel. Accordingly to the numerical simulation, a full injection will require 1995 seconds to complete, i.e. about 33 minutes.
Fig 3: Filling Factors at 300 seconds
Fig 4: Filling Factors at 600 seconds
When comparing the simulation flow front with the experimental one at a filling time of 10 minutes (600 seconds), the following results are achieved:
|Experiment (average)||138 mm||131 mm|
|Numerical (Shaper RTM)||136 mm||125 mm|
|Difference||1.44 %||4.58 %|
This post provides a first valuable benchmark of our new solver for RTM simulation, namely Shaper RTM. Despite being an alpha release still under development, the Darcy solver available in Shaper is to be able to predict Resin Injection with accuracy levels similar to the other commercial products on the market.
You can download and have a trial of this first release of Shaper RTM from the main Fast RTM website .
Would you like to have any early commercial information about the solver, don’t hesitate to get in contact with us at firstname.lastname@example.org
This work is made possible thanks to Innovate UK funding. iChrome wishes to thank the FastRTM project partners for the work done so far.