Notch Sensitivity under Fatigue

Polymers can be sensitive to stress concentrations or notches under fatigue loading as metals are, but generally they are less sensitive. The notch sensitivity factor (ft) is defined as follows  

The stress concentration factor is used in two essentially equivalent ways. The endurance limit of the material is reduced by dividing the nominal value by the stress concentration factor or the applied stress is magnified as shown 

FIGURE 4.13 Notch sensitivity of polymers. (Adapted from Balazs, C. R, Proc. 4th Annual Plastics Conf., Eastern Michigan University, September, 1969, pp. 20-45.) 

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Fujii T, Shina T, Okubo K. Fatigue notch sensitivity of glass woven fabric composite having a circular hole under tension/torsion biaxial loading. J Compos Mater 1994 28(3) 234-51. 

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