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Thin-walled structures have been widely used in various structural applications asimpact energy absorbing devices. During an impact situation, thin-walled tubesdemonstrate excellent capability in absorbing greater energy through plastic deformation. In this paper, a review of thin-walled tubes as collapsible energy absorbers is presented.As a mean of improving the impact energy absorption of thin-walled tubes, the influence of geometrical parameters such as length, diameter and wall thickness on the response of thin-walled tubes under compression axial loading are briefly discussed. Several design improvements proposed by previous researchers are also presented. The scope of this review is mainly focus on axial deformation under quasi-static and dynamic compressive loading. Other deformations, such as lateral indentation, inversion and splitting are considered beyond the scope of this paper. This review is intended to assist the future development of thin-walled tubes as efficient energy absorbing elements.

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Bone drilling is a universal surgical procedure commonly used for internal fracture fixation, implant placement, or reconstructive surgery in orthopedics and dentistry. The increased temperature during such treatment increases the risk of thermal penetration of the bone, which may delay healing or compromise the fixation’s integrity. Thus, avoiding penetration during bone drilling is critical to ensuring the implant’s stability, which needs surgical drills with an optimized design. Bovine femur and mandible bones are chosen as the work material since human bones are not available, and they are the closest animal bone to human bone in terms of properties. In the present study, the Taguchi fractional factorial approach was used to determine the best design of surgical drills by comparing the drilling properties (i.e., signal-to-noise ratio and temperature rise). The control factors (spindle speed, drill bit diameter, drill site depth, and their levels) were arranged in an L9 orthogonal array. Drilling experiments were done using nine experimental drills with three repetitions. The findings of this study indicate that the ideal values of the surgical drill’s three parameters combination (S1D1Di2) and their percentage contribution are dependent on the drilling levels of the parameters. However, the result shows that the spindle speed has the highest temperature effect among other parameters in both (femur and mandible) bones.