Bounds of Application of the Sensing Block Method for Measuring Dynamic Load

In recent years, an increasing interest has been paid to the accurate measurement of stress-strain relations of materials for wide range of strain rates which are needed to formulate the constitutive equations of rate-sensitive materials precisely. The Hopkinson Pressure Bar system is widely used for this purpose. However, the device should be long enough to prevent the immediate reflection of stress waves from the ends of the input and output bars. The newly developed Sensing Block (SB) system, which consists of a small sensing projection and a relatively large mass block, is expected to be used widely for many materials. In this paper, the bounds of application of the SB method for measuring dynamic load was examined numerically. The relation between the size of sensing projection and the rising time of applied load was cleared to satisfy some criterions on the accuracy for each model. The results ensure the sufficient accuracy for measuring dynamic load under the obtained conditions.