Theoretical Considerations O Toughness of Short-Fibr-Reinforcd Thrmoplastics

In the present paper the emphasis is put on theoretical consideration of the mechanical behavior of short-fiber-reinforced composites. Starting from the concept of microscopic construction of composites, the dominating microscopic failure mechanisms are investigated and the relation to macroscopic properties such as stiffness, strength, fracture toughness, and work of fracture is explained. We do not discuss economic or technological matters. Technology is considered only as far as it influences structure of short-fiber-reinforced thermoplastics (cf. Sec. 2). Furthermore, we have restricted our considerations to short-fiber and discontinuous-long-fiber-reinforced composites, typical of fiber reinforced thermoplastics. The content reflects mainly the ideas developed in recent years at the Institute of Polymer Technology and the Central Institute for Solid State Physics and Material Research of the Academy of Sciences of the GDR in Dresden.