Energy release rates in a constrained epoxy disc with Hookean and Mooney–Rivlin materials

Assuming that the disc material can be modeled either as Mooney–Rivlin or as Hookean and the steel ring enclosing the disc as Hookean, the energy release rates as a function of the crack length are evaluated and compared. Two loadings are considered––one in which the surface of the star shape hole in the disc is loaded by a uniform pressure and the other in which the temperature of the composite body is uniformly raised. It is found that the linear and the nonlinear analyses give qualitatively similar results for the two loadings. For each load, the energy release rate increases with an increase in the starter crack length, reaches a maximum value and then decreases gradually.     

A theory of finite elastic consolidation

Presented in this paper is a general theory describing the consolidation of a porous elastic soil. The formulation allows for the occurrence of finite geometry changes and finite elastic strains during the consolidation process. The governing equations have been cast in a rate form and the laws which determine deformation and pore fluid flow, i.e. Hooke's law and Darcy's law, are presented in a frame indifferent manner. A numerical technique is described that provides an approximate solution to the governing equations. The theory and the solution technique are illustrated by several examples of practical interest.     

On the temperature rise at the tip of a fast running crack2

The high energy concentration at the tip of a running crack leads to irreversible deformations, and a great amount of the deformation energy is set free as heat. Assuming that this moving heat source is of circular shape, the temperature distribution around the crack tip has been calculated. The temperatures are dependent on the radius of the heat source and the crack velocity. Some examples for the material glass are given. The very high temperatures computed lead to the supposition that the observed light emission during fast fracture is of thermal origin.     

Dynamic plastic response of foil gages

Little research has been devoted to the accuracy of the response of resistance strain gages to dynamic plastic strain because of the lack of an easy-to-use comparative strain-measuring technique. The dynamic interferometric strain gage provides a suitable standard of comparison. Foil-gage response is compared directly with interferometric strain-gage response in a longitudinal-impact experiment. The accuracy of the foil gage does not decrease with increasing maximum strain (up to 8 percent). The error in shape of the strain wave does not vary drastically with distance from the point of impact. In contrast to previous work, foil gages are found to be reasonably accurate strain transducers for dynamic plastic strain.     

Elastic modulus and yield stress of suspensions

A recent technique, developed to measure yield stress has here also been used to determine the elastic modulus of a suspension. Temperature effects have been measured.     

Frictional instability of a train of elastically connected bodies

Leningrad State Steelworks Research and Design Institute. Leningrad Mining Institute. Translated from Prikladnaya Mekhanika, Vol. 25, No. 7, pp. 110–115, July, 1989.