Hybrid aluminum/composite specimens of the thin–walled square cross–section under flattening experiments

Thin–walled specimens are widely used in various applications, such as automotive bumper, buildings, bridges and warehouse shelve. Investigation of a reinforcement composite coating on sides of thin–walled metal specimens can be valuable, based on their collapse behavior. This article performs an experimental study to investigate energy absorption characteristics of hybrid aluminum/composite specimens of thin–walled cross–section under quasi–static lateral loading; and also, to optimize them by the Taguchi method. To achieve the goals, experimental specimens are manufactured in three different groups. Some thin–walled aluminum specimens are produced by the extrusion and tested as simple specimens or the benchmark (the first group). Then, as the second group, each vertical edge of some aluminum specimens is reinforced by a composite coating. Four different glass fibers and two different resins are used to produce the hybrid specimens. Each specimen of the second group is reinforced by a certain fiber type and with 1, 3, or 5 layer numbers; and their crashworthiness properties are measured during the flattening tests. Effects of fiber types and layer numbers of the composite stiffener are investigated on crushing behavior of the hybrid samples. Their results illustrate that hybrid metal/composite specimens with a 5–layer stiffener has the best performance. Therefore, as the third group, design of experiments is performed by the Taguchi method and several optimized hybrid specimens are introduced as the main output of the optimization process. Results illustrate that total absorbed energy of some reinforced specimens are 6.21 times of the corresponding value of the benchmark.