Journal of Materials Science

, Volume 26, Issue 16, pp 4468–4476 | Cite as

Notch-sensitivity of non-linear materials

  • P. Purslow


The relationships between breaking stress, σB, and crack length, a, and between breaking strain, εB, and a have been calculated for materials whose stress-strain behaviour is approximated by σ=kε n . The results take the form σB∝ (a) m and εB∝ (a) p, where m=n/(n+1) and p=1/(n+1). For n=1 (the linear case), m=p=1/2. For n>1, m>1/2>p and for n<1, m<1/2<p. Tests on butyl, silicone and latex rubbers as model materials confirm the applicability of the theory. The results imply that for biological materials such as skin where n>1, σB drops off very rapidly with increasing defect size, whereas εB is far less dependent on a. These may be appropriate properties for a material where the degree of extension, rather than the peak loads encountered, is critical to its in vivo performance. For materials where n<1, breaking stress is far less sensitive to crack length than fracture strain, which may be more appropriate properties for applications in which applied stress, but not strain, is critical.


Polymer Silicone Rubber Butyl Crack Length 
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Copyright information

© Chapman & Hall 1991

Authors and Affiliations

  • P. Purslow
    • 1
  1. 1.Muscle Biology DepartmentAFHC Institute of Food ResearchLangfordUK

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