Use of Rapidly Cured Inflatable Composite Beams For Military Small-Gap Bridging

This study investigates the viability to used rapidly cured fiberglass composite tubes to defeat gaps thru experimentally and numerically techniques. Fiberglass pipes of 3.8in diameter and 48in long were instrumented and loaded to determine its mechanical properties based on load deformation and strain characteristics. Load cells, LVDT, strain gauges and data logger were used. Two strain gauges were attached outside the pipes, top and bottom at mid-span. A loading machine of 10-ton capacity was used to impose line load at rates of 1500 and 2000 lb/min. Results indicate that, rate of loading has no significant effects on the stiffness of fiberglass pipes. Nonlinear 3-D finite element analysis program was employed. It has been shown that, linear elastic prediction can capture pipe load-deformation response up to 5% strain. The calibrated numerical tool and the refined material parameters were used efficiently and realistically for further modeling and analysis the composite tubes subjected to military vehicle loads. Shell elements with the composite properties were utilized. Full scale 37.25 inch diameter pipes were tested first in the laboratory and then in the field with military vehicles. Results show that the pipes can sustain large deformations without failing and return to its previous shape due to its elastic properties. Since deformations are not a major concern for a short term gap defeats, they are an appropriate solution to the gap problem.