Fiber breakage

The single-curve blade (Fig. 18-41d) was developed for incorporating fiber reinforcement into pasties. In this application, the individual fibers (e.g., sisal or glass) must be wetted with polymer without incurring undue fiber breakage. 

Improper use of dryers to enhance cleaning can result in shorter staple because of fiber breakage and in lower marketable weight because of excessive moisture loss (40). Conclusions and recommendations for optimum dryer operation are as follows ... 

While UV-vis fibers are much less prone to fiber breakage than mid-IR fibers, excessive mechanical stress may still break the fibers. The miifimum bending radius as specified by the supplier should be observed, and excessive mechanical stress should be avoided. 

Since the loading is assumed to be perfectly symmetrical about the fiber center, fiber breakage is always expected to occur at the center (z = 0)... 

The above observations may be interpreted as follows. Prior to rupture in the glass/epoxy system, the stressed specimen suffers minor failures (primarily fiber breakage and epoxy cracking) which produce EE similar to that of the pure components. These failures accumulate, leading to strand rupture and a large amount of interfacial failure between filaments and epoxy. It is this latter form of... 

As straining proceeds, the debonded region grows with increasing strain. At the point of fiber breakage, the strain is ei = = oj/Ef, and the debonded regions have length-... 

Of the three physical properties covered in this chapter, optical properties have the least importance in composite and biological applications. This is not to say that there are no applications of optical properties in composites or biological materials. There are indeed, such as the use of birefringence in the analysis of stress distribution and fiber breakage in fiber-matrix composites [14] and in the development of materials for ophthalmic implants such as intraocular devices [15]. These topics are beyond the scope of this text, however, even as optional information, and introduce no new concepts from a material property standpoint. There are many interesting articles and... 

Figure 10. Correspondence between fiber breakage and the number of AE events for SFC specimens with three different diameter fibers 15 fan ( A), 35 fan ( ), and 92 fan (O).

The earliest works of trying to model different length scales of damage in composites were probably those of Halpin [235, 236] and Hahn and Tsai [237]. In these models, they tried to deal with polymer cracking, fiber breakage, and interface debonding between the fiber and polymer matrix, and delamination between ply layers. Each of these different failure modes was represented by a length scale failure criterion formulated within a continuum. As such, this was an early form of a hierarchical multiscale method. Later, Halpin and Kardos [238] described the relations of the Halpin-Tsai equations with that of self-consistent methods and the micromechanics of Hill [29],... 

---