Showing papers by "Vaughn College of Aeronautics and Technology published in 1971"

Creep in oriented thermoplastics

Abstract: Sheets of oriented low-density polyethylene possessing transverse symmetry were prepared by simple tensile drawing at room temperature. The degree of anisotropy was varied by varying the draw ratio. Classic elasticity theory shows that five constants are necessary to characterize the deformation behavior of an elastic material possessing such symmetry. The time-dependent equivalents of these constants have been determined from the simultaneous measurement of longitudinal and lateral strain during tensile creep of specimens cut at 0, 45, and 90 deg to the draw direction. Special creep apparatus, able to handle small, flexible specimens, was developed for this study. The shear compliance obtained from the tensile creep studies was in good agreement with the value obtained from torsional creep measurements on a 0-deg specimen, for the entire range of draw ratios. The contraction measurements have been used to provide additional evidence for deformation mechanisms suggested by the longitudinal strain...

Some observations of the atomizing characteristics of air-blast atomizers

Abstract: Summary An optical method of measuring mean droplet size of sprays due to Dobbins is described and has been used to assess the effect of operating variables on the characteristics of an air-blast atomizer. Simple variations in the design of the atomizer indicate ways in which its performance may be improved. Measurements of mean droplet size with ambient pressures ranging from atmospheric up to 200 lb/in2 abs and air-to-fuel ratios covering a wide range show some of the potential advantages of air-blast atomizers for high-pressure gas-turbine engine application.