THE DESIGN OF THE THIN-WALLED HYBRID BEAM WITH A SECTION OF SINGLE-HAT
This result suggested that the thin-walled hybrid beam can yield the deformation with the best energy-absorption effect in the axial crashing process when the combination of (t, R, d) taken the values of (1.75mm, 3.25mm, 29.48mm), which can also adapt to the errors of manufacturing and measurement.
The dynamic analysis procedure using an analytical model for hybrid beams subjected to blast loads consists of several steps: describing the basic assumptions of the analytical model, obtaining the mathematical model of the system, estimating the ultimate bending moment capacity of the CFRP-metal hybrid beam, and calculating the maximum and permanent deformation of the hybrid beam.
Figure 1 shows the schematic of a CFRP-metal hybrid beam. The rectangle is the fundamental beam section shape, and the analysis method can be extended to I-section or tubular beam by proper modification.
The experimental results and the FE analyses have demonstrated that debonding seldom occurs and that fiber breakage is the dominant failure mode in the hybrid beam; thus, the slip between the aluminum beam and the CFRP can be ignored at the interface.
The ultimate bending moment of the hybrid beam can be thus written as
The Permanent Deformation of the Hybrid Beam. Mathematically speaking, external overpressure pulse loadings with a finite impulse of infinitely large magnitude and an infinitesimally short duration are known as impulsive, and Dirac's delta function is used to describe this behavior.
The FE model simulates the hybrid beam as realistically as possible; so the assumptions of the analytical solution are not made for the FE model.
Deflection of the Whole Hybrid Beam. Figures 9 and 10 show the deflection of the CFRP-aluminum hybrid beam under impulsive loads by the application of explosives.