Compression molding simulation with cross-rib geometry

Compression molding of discontinuous long-fiber reinforced plastic results in fiber deformation, localized orientation, and weld line generation. These characteristics affect the strength of the part, so they must be predicted accurately.

Use Cases Highlights

Discontinuous fiber reinforced material compression forming analysis
Fiber orientation and weldline predicted
Predict Matrix Resin Rich domain

Fiber details

In this case study, the forming material is discontinuous long-fiber reinforced plastic called Randomly-Oriented Fibers (ROF).

Material: Tepex^® flowcore (Bond-Laminates GmbH)
Glass fiber length: 30 - 50mm
Fiber orientation: 2D Random orientation
Fiber volume content (VF): 47%
Matrix resin: Nylon 6 (Polyamide)

ROF type discontinuous long-fiber reinforced plastic: Actual material (left), Simulation model (right)

Result

To evaluate the beam-in-solid coupling method, a compression molding test with a cross-rib geometry was performed. A comparison between the deformation observed mid-way through the test and the corresponding simulation results shows good correlation, particularly in the following areas:
- Deformation behavior of fibers and resin
- Formation of weld lines based on fiber orientation

Comparison between the mid-test deformation geometry (left) and the simulation result (right)

From the simulation result, fiber orientation can be evaluated by looking at the beam elements. It also shows a region at the base of the rib where there are less fibers (a matrix resin rich region). Similarly, by looking at the deformation geometry of solid elements, a weld line can be seen. The weld line at the tip of the rib is found in both the simulation and the test.

Deformed geometry of fiber (beam) and matrix resin (solid)