PRACTICAL USE OF THE STATISTICALLY MODIFIED LAMINATE MODEL FOR INJECTION MOLDINGS - PART 1 - METHOD AND VERIFICATION

The fibers in injection molded FRP provide the material's strength and stiffness; however, they also supply many of the problems. Preferenti al orientation of fibers during molding can reduce strength and stiffn ess below expected values in critical directions, or induce warpage in thin walled sections. Makers of short fiber reinforced injection mold ed products typically use computer aided engineering packages to optim ize product performance and manufacturing variables. However, the reli ability of the fiber orientation simulation can be limited, and the me thod is not easily understood, making an assessment of accuracy for a given situation difficult. In addition, the structural module of flow analysis packages is often a basic package with many features missing. This paper presents a structural analysis system for injection molded parts made of short fiber reinforced plastics. A full-featured commer cial structural analysis code is interfaced with a flow analysis progr am using a practical material model that takes into account the effect s of local fiber orientation. The system is completely open to the use r, and can be modified as required.