Simulation of short fiber reinforced composites

Besides standard plastic materials, more and more short and long fiber reinforced plastic materials are used to manufacture automotive components, aircraft parts, sports equipment and standard household appliances. This development is due to the higher requirements for stiffness and strength. Nevertheless, the costs of production shall be kept low, using special manufacturing techniques. Since the local properties of this group of materials are highly dependent on the production process, not only new material models are necessary, which allow to consider the complex load bearing capabilities and damage mechanisms of these materials properly, but also new modeling techniques allowing to close the simulation process chain for these materials.

Short fiber reinforced composite components are usually manufactured using an injection or compaction process. Thereby, carbon or glass fibers with a length of approximately 0.1 mm to 1.0 mm are brought into final shape together with a resin material. Strong local anisotropies in such material lead to complex structural mechanic effects which need to be captured within the simulation. In this course, material models being available in LS-DYNA, some of them even developed at the DYNAmore Company are introduced and discussed. Since the consideration of the manufacturing process of such components plays an important role to be predictive in the structural analysis, different possibilities to consider results from other software tools used for the process simulation will be introduced. This way, the simulation process chain is closed for this specific group of materials using the software tool ENVYO^® which is introduced within this course as well. Thereby, several homogenization strategies and the respective input parameters will be discussed and illustrated in application examples.

Contents

• Introduction to composite materials
• Explanation of anisotropy and direction definitions
• Material modeling
• Introduction and discussion of material models being available in LKS-DYNA for short fiber reinforced composite modeling
• Failure criteria established by Tsai-Hill, Tsai-Wu and *MAT_GENERALIZED_DAMAGE
• Evaluation of process simulation results (esp. injection molding)
• Homogenization strategies
• Mori-Tanaka, self-consistent method
• Closure-Approximations
• Introduction into ENVYO^® to close the simulation process chain for short fiber reinforced composites