A determination of dewetting in a biaxial stress field.

摘要

An experimental investigation of dewetting in uniaxial and biaxialstress fields was conducted for infinitesimal strain levels.An optical technique was attempted with limited success, whichdemonstrated the need for more precise measurements at smallstrains. A method was developed for stiffening the surface of thepropellant test specimen with commercial bonding cement, whichfacilitated the use of strain gages on the stiffened surface. Ananalytic expression was derived which relates measurements madeon the outer surface of the cement to internal propellant behavior. It was noted that dewetting commenced at strain levels of theorder of zero strain, and that there was little variation with stressratio in the strain at which dewetting commenced. Dewetting appearedto be complete at lower strains for higher stress ratios.Dewetting was noted to be at such low strain values that thephenomenon is considered to be inconsequential in a practical engineeringanalysis of this propellant.