Accession Number : AD0660384

Title :   THE PERMANENT DEFORMATION OF A PORTAL FRAME SUBJECTED TO A TRANSVERSE IMPULSE,

Corporate Author : BROWN UNIV PROVIDENCE R I DIV OF ENGINEERING

Personal Author(s) : Johnson,G. L. ; Martin,J. B.

Report Date : AUG 1967

Pagination or Media Count : 86

Abstract : A study was made of the inelastic response of a rectangular portal frame with a mass attached to the center of the beam to an impulsive load transverse to the plane of the frame. The material was considered to be rigid-plastic, and the interaction between bending and torsion was considered on the basis of a rectangular yield curve. The ratio of the frame mass to the attached mass gamma and the ratio of limit torsion moment to limit bending moment beta were considered as variables. An exact rigid-plastic analysis was presented for a limited range of values in the beta-gamma domain. This limited exact analysis was used to construct a simple two degree of freedom solution to a different initial value problem which was valid over the entire beta-gamma domain. It was shown in a rational manner that the two degree of freedom solution can be considered as a good approximation to the original problem. Experiments were carried out on steel and aluminum frames. The impulsive load was obtained by detonating blasting caps against the attached mass. The experiments showed evidence of the effects of the dependence of yield stress on strain-rate. When the rate sensitivity is included in the two degree of freedom solution in an approximate manner, good correlation between theory and experiment is obtained. (Author)

Descriptors :   (*STRUCTURES, *LOADS(FORCES)), DEFORMATION, STRAIN(MECHANICS), SENSITIVITY, MODEL TESTS, STEEL, ALUMINUM, STRUCTURAL PROPERTIES

Subject Categories : Structural Engineering and Building Technology

Distribution Statement : APPROVED FOR PUBLIC RELEASE