Fatigue performance of polypropylene and related composites

This fracture mechanical approach has been successfully applied for both neat [2-3] and short (SGF) and long glass fiber (LGF) reinforced PP [3-4]. It was found that the stable FCP behavior, which is a part of the da/dN versus AK curves, can be described by the well-known Paris-Erdogan relationship  

In FCP studies performed on neat and discontinuous GF reinforced PP composites, it was found that the stable acceleration range is often preceded by a stable deceleration one [2-4]. The appearance of this range is due to a blunting process in which different matrix- and fiber-related events are involved. 

For this case, a similar description to equation (1) is used  

It should be noted here that the primary crack growth results in static fatigue can also be represented in another form initial fC, versus time to failure (tf). By extrapolation of the related curve, the threshold Kj value can be determined below which no crack growth occurs. This description is favored in ESC studies [1]. 

As mentioned above, the fatigue behavior with damage development should be assessed by the Wohler curve and the fatigue endurance limit. The latter value is the most important parameter for design and construction purposes. For the description of the Wohler curves, different methods can be selected according to the plotting (semi- or double logarithmic scale). 

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Fatigue performance of polypropylene and related composites FATIGUE CRACK PROPAGATION... 

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