Common practice of surgical treatments in orthopaedics and traumatology involves cutting processes of bone. These operations introduce risk of thermo-mechanical damage, since the threshold of critical temperature producing thermal osteonecrosis is very low. Therefore, it is important to develop predictive tools capable of simulating accurately the increase of temperature during bone cutting, being the modelling of these processes still a challenge. In addition, the prediction of cutting forces and mechanical damage is also important during machining operations. As the accuracy of simulations depends greatly on the proper choice of the thermo-mechanical properties, an essential part of the numerical model is the constitutive behaviour of the bone tissue, which is considered in different ways in the literature. This paper focuses on the review of the main contributions in modelling of bone cutting with special attention to the bone mechanical behaviour. The aim is to give the reader a complete vision of the approaches commonly presented in the literature in order to help in the development of accurate models for bone cutting.

This paper focuses on the numerical analysis of the ballistic performance of Kevlar®-29 under impact of different double-nosed stepped cylindrical projectiles. Numerical modelling based on finite element method was carried out in order to predict the failure mode of the target as well as the ballistic limit. A detailed analysis of the ballistic limit, failure mode and deformation of the targets due to impact of double-nosed projectiles was developed, discussed and compared with those involved in penetration of single-nosed flat and conical projectiles. Significant influence of the projectile geometry was demonstrated: the lowest ballistic limit was obtained with the conical–conical nose shape projectiles.

The biomechanics of the spine is experimentally assessed in terms of range of motion and overall stiffness. Quantification of the surface strain distribution is currently limited either to the vertebrae or the discs, whereas a full-field approach to measure the strain distribution in a multi-vertebra segment is currently missing. The aim of this work was to explore the feasibility of using Digital Image Correlation (DIC) to measure the strain distribution simultaneously on the vertebral bodies and the intervertebral discs of spine segments in different loading configurations. Three porcine spine segments were tested. A white-on-black speckle pattern was prepared which covered the hard and soft tissues. Two different loading configurations (flexion and lateral bending) were reproduced, while two sides of the spine were analyzed with DIC. Measurements were successfully performed on the entire region of interest of all specimens, in both configurations. The DIC analysis highlighted the strain gradients present on the spine segments including tension and compression associated with bending, the direction of principal strains in the different regions, as well as bulging of the discs under compression. Strains of tens of thousands microstrain were measured in the discs, and below 2000 microstrain in the bone. This work showed the feasibility of applying DIC on spine segments including hard and soft tissues. It also highlights the need for a full-field investigation, because of the strain inhomogeneity in the vertebrae and discs.