Experimental and numerical study on bending collapse of aluminum foam-filled hat profiles

The deep bending collapse of thin-walled empty and foam-filled hat profiles are studied experimentally and numerically. The deep bending tests involve two steps. First, the bending tests are run in a conventional three-point bending mode up to approximately 40 degrees rotation. Then, the bent specimens are loaded vertically in compression, and are bent further up to 150 degrees. These tests revealed salient features of empty and foam-filled hat members subjected to large bending rotations. The moment-rotation characteristics of the generalized plastic hinges with the rotation angle up to 150 degrees are obtained experimentally, and they are found to be qualitatively similar to the case of axial folding of thin-walled members, with peaks and troughs on M-theta curves corresponding respectively to the initiation of foldings and jammings. It is found that foam-filled members provided a 30-40% increase, compared to traditional non-filled members, of the specific energy absorption. Numerical study using explicit nonlinear finite element method are also conducted. Quasi-static simulations of deep bending collapse of empty and foam-filled single-hat beams are carried out. Numerical results are compared with the experimental results showing good agreement. (C) 2001 Elsevier Science Ltd. All rights reserved.