Polymer pre-notched small punch specimens to evaluate the essential work of fracture (EWF) parameters

• The EWF method can be applied to pre-notched miniature specimens.
• Upper and lower limits for the ligament length have been established.
• The weP-SPTweP-SPT term can be compared with that obtained in DDEN-T specimens we.
• The weP-SPTweP-SPT value is approximately 3 times that of the we value for the polymer analyzed.

Standardized deeply double edge notched tensile specimens (DDEN-T) have been usually used to assess fracture properties in thin polymer plates under plane stress conditions. The methodology is based on a multi specimen technique and is well known as the essential work of fracture (EWF) method. In some special circumstances these standard specimens cannot be machined as could be the case if the material is limited. A possible solution proposed in this paper could be the use of pre-notched small punch test specimens, in which the aim is to establish the feasibility of using pre-notched SPT specimens for evaluating the essential work of fracture parameters. The results obtained with these miniature specimens have been compared with those obtained from standard DDEN-T specimens.

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