Residual Stresses and Birefringence in Injection Molding of Semicrystalline Polymer
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X. Guo
Abstract
A composite model for the buildup and the relaxation of residual stresses and birefringence during the injection molding of semicrystalline polymer is proposed. This model takes into account the flow-induced crystallization occurring under nonisothermal conditions. The effects of crystallization on the variations of mechanical and physical properties are considered. The viscoelastic constitutive equation due to Giesekus and Leonov is employed for the calculation of the buildup and relaxation of flow stresses, whereas the Morland-Lee constitutive equation of linear viscoelasticity is utilized for the calculation of the buildup and relaxation of thermal stresses during the molding. The overall residual stresses in the molding are determined based upon the addition of residual flow and thermal stresses. The multilayered micro-structure in the moldings arising due to the flow-induced crystallization is determined. Flow birefringence is related to flow stresses according to the stress-optical rule. An expression is proposed to evaluate the overall residual birefringence based upon the resultant microstructure pattern and residual low birefringence in the moldings. As a result, numerical simulations for idealized injection molding process are formulated to calculate the residual stresses and birefringence in molded semicrystalline polymers. Based upon the above theoretical approach, the numerical simulation schemes are formulated, and a computer program is developed. Based upon the simulations, the effects of molding conditions and molecular weights on the overall residual stresses and birefringence are further evaluated.
© 1999, Carl Hanser Verlag, Munich
Artikel in diesem Heft
- Editorial
- Fifth of a Series: Pioneer of Polymer Processing John Wesley Hyatt (1837–1920)
- Internal Mixer
- Modeling the Distributive Mixing in an Internal Batch Mixer
- Biomedical Engineering
- Processing of Biodegradable Polymer Composites as A Drug Delivery System in Vitro
- Fibers and Films
- Tensile Force Measurements in the PA 6 High Speed Fiber Spinning and their Utility
- Crosslinking Modification of UHMWPE Fibers by Ultra-violet Irradiation
- Effect of Wall Slip on Rheotens Mastercurves for Linear PE Melts
- Stability of a Blown Film Extrusion Process
- Molding
- Blank Design and Fiber Orientation Distribution During Compression Molding of GMT
- Injection Moulding of a Commercial β-Nucleated Polypropylene
- Weld Line Strength in PC/ABS Injection Moldings
- Computer Controlled Rotational Molding of a Hollow Femur for 3-D Photoelastic Analysis
- Residual Stresses and Birefringence in Injection Molding of Semicrystalline Polymer
- Residual Stresses and Birefringence in Injection Molding of Semicrystalline Polymer
- Generalized Predictive Observer-Controller For Injection Moulding
- Fiber Orientation in 3-D Injection Molded Features
Artikel in diesem Heft
- Editorial
- Fifth of a Series: Pioneer of Polymer Processing John Wesley Hyatt (1837–1920)
- Internal Mixer
- Modeling the Distributive Mixing in an Internal Batch Mixer
- Biomedical Engineering
- Processing of Biodegradable Polymer Composites as A Drug Delivery System in Vitro
- Fibers and Films
- Tensile Force Measurements in the PA 6 High Speed Fiber Spinning and their Utility
- Crosslinking Modification of UHMWPE Fibers by Ultra-violet Irradiation
- Effect of Wall Slip on Rheotens Mastercurves for Linear PE Melts
- Stability of a Blown Film Extrusion Process
- Molding
- Blank Design and Fiber Orientation Distribution During Compression Molding of GMT
- Injection Moulding of a Commercial β-Nucleated Polypropylene
- Weld Line Strength in PC/ABS Injection Moldings
- Computer Controlled Rotational Molding of a Hollow Femur for 3-D Photoelastic Analysis
- Residual Stresses and Birefringence in Injection Molding of Semicrystalline Polymer
- Residual Stresses and Birefringence in Injection Molding of Semicrystalline Polymer
- Generalized Predictive Observer-Controller For Injection Moulding
- Fiber Orientation in 3-D Injection Molded Features
