On the Buckling of Sandwich Beams Containing an Unbonded Region.
Abstract
This study involves a combined experimental and analytical analysis of the stability of a sandwich beam (overall length of 16.5 inches) with a partially unbonded faceplate. For simplicity, the beam considered was simply supported. Fully bonded beams as well as beams with unbonded lengths ranging from 0.5 to 5.0 inches were tested. Two failure regimes were observed. A distinct collapse load was evident in experiments with short unbond lengths (< or = 2.0 inches). The loading histories of beams with longer unbond lengths (< or = 3.0 inches) were found to be characterized by a limit load. In all cases, a transition form a symmetric to a nonsymmetric buckling shape occurred. The presence of the unbonded region was found to drastically reduce the load-carrying capacity of the sandwich structure. A power-law relationship was found between the unbond length and maximum load. The bonded sandwich beam was modeled as an assembly of three beams. This structure was assumed to be initially geometrically perfect. A solution was found numerically and began when the load within the unbonded faceplate was greater than the Euler buckling load for that section. Limit loads were predicted for all unbond lengths. The model was found to predict the failure load of a sandwich beam (unbond lengths < or = 2.0 inches) to within 12.5%.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1986
- Accession Number
- ADA173603
Entities
People
- Carl J. Frushon
Organizations
- Air Force Institute of Technology