Aging , small punch

A novel method is the small punch analysis, or pin on disk test, which is used to evaluate the weight loss of friction material. It is performed with a metallic pin in friction contact on a sample (small disk) the pin, moving cyclically, yields a stress-strain curve related to the specimen wear. This test is generally performed on retrieved, or aged, UHMWPE components. 

Transmission eiectron microscopy Fourier transform infrared spectroscopy (ASTM i42i, F2i02) b = Small punch (Kurtz etal. 1999) Accelerated aging (ASTM F2003-02) ... 

FIGURE 16.5 Ultimate load in the small punch test for (A) 30kGy irradiated in nitrogen and (B) 75kGy irradiated in air GUR 1020 specimens with 0-500ppm vitamin E and aged 0-4 weeks (ASTM F2003). Similar results were observed for GUR 1050. Adapted from [39]. 

How, then, are we to interpret values in the literature for in vivo oxidation in retrievals Current studies of mechanical behavior in shelf aged components and retrievals, whether based on miniature uniaxial tensile specimens or the small punch test, exhibit considerable variability and scatter, even when oxidation values are measured directly from the miniature specimens themselves. Consequently, published data for the relationship between in vivo oxidation and mechanical behavior are necessarily statistical in... 

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