Use of double clip gauge method to measure the plastic rotational factor rp

The value of the plastic rotational factor r_p at initiation in 3-point bend specimens with deep and shallow notches has been studied by using the double clip gauge method and it is shown that r_p is decreasing with decreasing of a/W, the experimental results agreeing well with the experimental results by using a clip gauge and catalytically hardening silicone rubber Unitex Xantropren Blue dental impression material.