Torsion—Resistant Structures: A Nature Addressed Solution

Abstract

The complexity of torsional load, its three-dimensional nature, its combination with other stresses, and its disruptive impact make torsional failure prevention an ambitious goal. However, even if the problem has been addressed for decades, a deep and organized treatment is still lacking in the actual research landscape. For this reason, this review aims at presenting a methodical approach to address torsional issues starting from a punctual problem definition. Accidents and breaks due to torsion, which often occur in different engineering fields such as mechanical, biomedical, and civil industry are considered and critically compared. More in depth, the limitations of common-designed torsion-resistant structures (i.e., high complexity and increased weight) are highlighted, and emerge as a crucial point for a deeper nature-driven analysis of novel solutions. In this context, an accurate screening of torsion-resistant bio-inspired unit cells is presented, taking inspiration specifically from plants, that are often subjected to the torsional effect of winds. As future insights, the actual state of technology suggests an innovative transposition to the industry: these unit cells could be prominently implied to develop novel metamaterials that could be able to address the torsional issue with a multi-scale and tailored arrangement.

Smart Biomechanical Adaptation Revealed by the Structure of Ostrich Limb Bones

“…These trabeculae form the spongeous bone near the epiphyses and, in the medullar cavity, form a complex structure of intersecting bone ridges, inclined at 45° with respect to the long axis of the bone ( Figure 2 ). Similar solutions are commonly exploited in different engineering applications to resist torsional stresses [ 44 ]. The bone ridges present in the medullar cavity of the femur act naturally as reinforcements to support the tensions and strengthen the structure to support the bending stresses imposed on the bone during the walking and running phases.…”

“…The material donated by MSNM is of unknown age and was kept in the collection with no data on its preservation or date of acquisition from the museum. The inner structure of the tibial bone presented remodelled tissues, with at least five bone rings, a clear indication that the animal, at the time of death, was an adult of at least five years old [ 31 , 44 ] (Castanet et al, 2000; Horner et al, 2000). The tibia was kept under environmental conditions.…”

Isolating the Role of Bone Lacunar Morphology on Static and Fatigue Fracture Progression through Numerical Simulations

“…To deal with the effects of meso-and micro-scale porosities and their interaction with cracks, preliminary two-dimensional (2D) and three-dimensional (3D) models have been implemented. Regarding the 2D XFEM models, huge interest is devoted to the analysis of the multi-toughening mechanism of the osteonic micro-structure and to the study of lacunar arrangements [23,24]. Lacunar voids are modeled as circles or ellipses, and cracks are inserted a priori in the computational model.…”

Tailored Torsion and Bending‐Resistant Avian‐Inspired Structures

“…The intrinsic complexity of torsional load, its 3D nature, its interplay with other stresses (especially bending), and its disruptive impact in several engineering sectors make torsional failure prevention an ambitious target. However, commonly designed torsion-resistant structures suffer from several limitations despite the wide range of applicative fields, such as civil, mechanical, marine, and biomedical engineering, [1] where torsional failures still represent widespread critical issues. Current torsion-resistant structures are characterized by articulated geometries, [2][3][4] high weight, [5] intricate design, [6] and high manufacturing costs.…”