An Elastic-Plastic and Strength Prediction Model for Injection-Molded Long-Fiber Thermoplastics

Conference · Mon Sep 01 04:00:00 EDT 2008

OSTI ID:939597

Nguyen, Ba Nghiep; Kunc, Vlastimil; Phelps, Jay; Tucker, III, Charles L; Bapanapalli, Satish K

This paper applies a recently developed model to predict the elastic-plastic stress/strain response and strength of injection-molded long-fiber thermoplastics (LFTs). The model combines a micro-macro constitutive modeling approach with experimental characterization and modeling of the composite microstructure to determine the composite stress/strain response and strength. Specifically, it accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length, orientation and volume fraction distributions in the composite formed by the injection-molding process. Injection-molded-long-glass-fiber/polypropylene (PP) specimens were prepared for mechanical characterization and testing. Fiber length, orientation, and volume fraction distributions were then measured at some selected locations for use in the computation. Fiber orientations in these specimens were also predicted using an anisotropic rotary diffusion model developed for LFTs. The stress-strain response of the as-formed composite was computed by an incremental procedure that uses the Eshelby’s equivalent inclusion method, the Mori-Tanaka assumption and a fiber orientation averaging technique. The model has been validated against the experimental stress-strain results obtained for these long-glass-fiber/PP specimens.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 939597
• Report Number(s): PNNL-SA-61147; VT0505000
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DEFORMATION
ELASTICITY
FIBERS
Injection-Molding
Long-Fiber Thermoplastic
Elastic-Plastic
Strength
Fiber Orientation
Fiber Length Distribution
Process Modeling
Finite Element Analysis
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MICROSTRUCTURE
ORIENTATION
PLASTICITY
RESINS
THERMOPLASTICS