The temperature and rate relationships of the crack resistance of polymethyl methacrylate with high loading rates

In this work for loading of the samples and measurement of theforces the Kol'skii com+posite rodmethod [i, 2] was used. The method of loadlng (Fig. 1) by cleavage is similar to that used earlier [3]. The explosive loading device 4 consists of an electric detonator, a layer of explosive, a metal striker, a foam buffer, and the measuring rod 5. The necessary form of stress loading wave is obtained by selection of the density and form of the buffer and of the striker weight. The contacting surfaces of the sample 6 and the rod 5 had a Class 7-8 surface finish and were lubricated with oil. The strain gauges 1-3 were located on the loading and the support rods at a distance of not less than five diameters from the ends of the rods. The cleaving force F and the mutual displacement A of the ends were determined from the recorded deformations at three cross sections of the rods with the use of the relationships