Image: MoldSim NL – Fiber orientation distribution; Nonlinear force displacement curve
Connecting Injection Molding and Structural Mechanics
In the development and design of components made of short-fiber reinforced plastics two types of simulations play a central role: first, the simulation of injection molding representing the manufacturing process and, second, anisotropic structure analysis in ANSYS providing a detailed description of the loading behavior of the components. CADFEM’s “Mold Sim NL inside ANSYS” combines both capabilities, and thus provides an integrated simulation concept to optimize product quality.
At BOSCH, this approach is specifically used for the integrated
simulation of short-fiber reinforced components in the field of automotive electronics. As a result, the material properties can be modeled accurately to yield a realistic prognosis about the thermo-mechanical behavior of the injection molded component (Fig. 1).
Fig. 1. Coupled simulation of injection-molded structure with MoldSim. Courtesy of Robert Bosch GmbH
The simulation of the filling process during injection molding also includes the calculation of fiber orientations caused by the flow behavior of the polymer melt. The different orientations of the fiber in the hardened component lead to a significant directional dependence of the material properties. The simulation of the mold filling process and the resulting locally varying distribution of fiber orientations are shown in Fig. 2 in the full article.
Based on the injection molding simulation, Mold Sim NL
enables the direct calculation of the anisotropic material parameters in ANSYS. Thus, plastic properties can be described
more accurately compared to simplified approaches, which
are based on isotropic behavior and scaled characteristics. A
complete integration is provided in ANSYS Workbench including
the import of the injection molding data, the efficient calculation
of the anisotropic material properties, as well as the
evaluation of results. Throughout the workflow, the user does
not have to leave the familiar interface of ANSYS. The embedding
of result data of external injection molding processes is
carried out via a specially designed menu on the Workbench
From ANSYS version 18 onward, CADFEM has developed a
new solution called “Mold Sim NL inside ANSYS”, which also
supports an elastic-plastic material description to consider
nonlinear material behavior of many composite matrix materials.
The plastic hardening parameters are determined
with robust curve fitting of test data using algorithms provided
by the Dynardo software optiSLang. The implementation
of an ANSYS wizard enables the user to follow a step-by-step
procedure from importing the experimental data,
over curve fitting, to saving the fitted parameters for future
To further enhance the new software solution, ANSYS Distributed
Memory Parallelization (DMP) was implemented.
In addition to the simulation of static-mechanical tasks
with Mold Sim NL, the user now also has the opportunity to
carry out modal and harmonic analyses of short-fiber reinforced
plastic components in linear dynamics.
Please refer to the full article for more details.
Authors: Matthias Werner (Robert Bosch GmbH), Ralph Echter (CADFEM GmbH)
Images: Fig. 1-3: by Courtesy of Robert Bosch GmbH
Title Image: Fotolia, XXLPhoto
This article was originally published in the CADFEM Journal
02 | 2017 and re-published in Dynardo’s RDO Journal