PLASTIC DEFORMATION IN BEAMS UNDER SYMMETRIC DYNAMIC LOADS
Abstract
Consideration is given to deformations in beams caused by dynamic loads distributed over finite lengths. The analysis is based on the assumption of plastic-rigid behavior in which elastic strains are neglected and the beam is assumed to be rigeid except at cross-sections where the limit, or fully plastic, moment is maintained. The main qualitative results appeared to be that the final deformation is the same as that in the case of concentrated loading unless the length over which the load is applied exceeds about one-third of the beam length. A quantitative investigation was made to show the modification of the final deformation resulting from a small degree of load spreading instead of that produced by a concentrated force. The final central angle produced by a series of loads was calculated for a square-wave force-time curve. The plotted results revealed that the deformation falls off very rapidly for large maximum loads. For a large load parameter micron m= 40, the deformation parameter dropped from about 800 for a concentrated load (k=0) to about 600 for k=0.05; the parameter k is defined by k=e/1, where e < or = to 1 and 21 is the length of the beam. The large reduction was attributed in part to the assumptions of a rectangular force pulse and a constant load intensity over the loaded beam segment. However, these results were beleived to indicate that the assumption of a mathematically concentrated load could lead to appreciable deformation overestimates.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1953
- Accession Number
- AD0023825
Entities
People
- J. A. Seiler
- P. S. Symonds
Organizations
- Brown University