Abstract
Most articles made from elastic substances are intended for service under dynamic conditions. Static methods of investigation are clearly insufficient for determining the behavior of elastic substances under dynamic conditions and therefore there has for a long time been a need for dynamic tests. In recent years several dynamic tests have been developed, and a number of investigations of elastic properties under dynamic conditions have been published. The works of Frumkin, Roelig, Kosten, Naunton and Waring and other investigators have established a series of relations in the behavior of elastic substances under dynamic conditions. However, the limited intervals of frequency and temperature in these experiments gave relations of peculiar character and even led to contradictions. Thus Naunton and Waring showed that, under dynamic conditions (at high frequencies), automobile tire casings act as solid hoops and, according to Roelig and Kosten, the relation between modulus and frequency, though still existing, is of relatively little importance. The development of a concept of the mechanism of highly elastic deformation, and in particular the disclosure of relaxation made it possible for Kornfel'd and Poznyak and Mikhai˘lov and Kirilina to demonstrate experimentally the existence of a more general law relating the phenomena. However, in their experiments, the frequency in both cases changed within narrow limits, and consequently these investigations too do not give a general picture of the behavior of elastic materials in relation to the frequency of deformation and temperature. The idea of highly elastic deformation, as well as that of relaxation, comes down to the fact that the magnitudes of the deformations observed depend on the relation between the time of action of the force and the time required for regrouping of the particles in the substance during the deformation.
Automobile tire sounds - acoustical grading system feasibility:
