Stringing or Crazing

The mechanisms described in the previous sections are fundamentally molecular, but are enhanced by mechanical losses in the bulk of the material. A particular mechanism which operates in adhesive joints is stringing. It was mentioned by RivUn, who had observed the way in which sticky tape adhesive pulled out into fibers near the crack tip. hi other words, the crack line did not remain straight but broke up into fibrous filaments which seemed to hold the crack faces together, as shown diagrarmnatically in Fig. 8.23. 

In fact, this type of separatim process is bound to happen if a thin layer of elastic material, like sticky tape adhesive, is trapped between two more rigid layers which are pulled apart. The stress within the thin layer is a bulk stress 

---