Abstract
Controlled flaws were introduced into poly(methyl methacrylate) samples in the presence of liquid acetone using a Vickers indenter over a range of indentation loads from 100 to 1400 N. Due to the large plastic zone underneath the indenter, the radial crack formed by indentation consisted of two halves, known as Palmqvist cracks, instead of a single semicircular crack. The strengths of the samples were measured in air either immediately following indentation or after a stress-relief anneal. The strength of the as-indented samples was about 6% less than that of the annealed samples; however, the dependence of strength on indentation load was similar for both sets of samples. These results were interpreted in terms of an indentation fracture mechanics model. The analysis is consistent with poly(methyl methacrylate) having a rising fracture toughness with increasing crack size.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
