Bending collapse of square tubes with variable thickness
Abstract This paper aims to study the bending collapse behavior of thin walled square tubes with variable thickness in the cross section. Three point bending test is carried out for thin walled square beams with different thickness for flanges and webs. The relative strength of the flanges versus the web plates is found to have significant influence on the force response and deformation pattern. Numerical simulation of the experimental test is also performed and the numerical results compared very well with the experimental results. Moreover, the difference between the quasi static and dynamic responses of the square tubes under transverse loading is analyzed. A response surface method is finally employed to optimize two thin walled beams under impact loading. The optimization results show that putting less material in flanges and more in the web plates is an efficient way to improve the bending resistance of the beams under transverse loading. Adopting graded thickness in the web plates is an effective and promising approach to further increase the energy absorption efficiency of the beams.