Correlation between Orientation and Mechanical Properties of Long-fiber Reinforced Thermoplastics

Fiber orientation and mechanical properties are important factors in understanding the characteristics of long-fiber reinforced plastics. Understanding this phenomenon will provide a product design guideline to satisfy the required physical properties and will also help to improve the accuracy of flow and structural analysis. We conducted evaluation of fiber orientation and mechanical properties using X-ray CT observation. A new fiber orientation evaluation methodology, which features a sophisticated２-dimensional Fourier transform calculation, has recently been introduced. Along with increased accuracy, this method establishes a profound interdependence between the wall thickness of test specimens and the discernible correlation between them. This study shows that fiber orientation has a direct influence on mechanical properties. In our investigation, we found a distinctive thickness dependency pattern in both the flow direction and transverse direction. Contrary to our expectations, the thickness dependency of physical properties exhibits an inverse relationship between these directions. Through careful analysis, we identified that the primary factor controlling this phenomenon to be the intricate fiber orientation of long fibers that determines the material behavior.