平行板プラストメーターの理論

抄録

The parallel-plate plastometer is a simple and important instrument to investigate rheological behavior of matter. Especially, it is very useful for materials which have yield values. But there is only Scott's theory for this case and he made rather rough assumptions in the beginning of the calculation, so it is not sure whether the final result is reasonable or not. We have made calculation starting from the general equation of motion for the Bingham solid and obtained the relationship between the thickness of the specimen h and the time t when a constant force is applied perpendicular to the plates. Calculations have been made for the two cases: (a) The specimen is larger than the plates; thus the area under compression is constant. (b) The plates are larger than the specimen; thus the volume of the specimen is constant. Our final results (34) and (40) enable us to determine the yield value and the coefficient of plastic viscosity η. And our results reduces to the equations derived by Stefan and Healey when the yield value f is neglected.