An exception to every rule; high velocity impact not always required for bilateral 1st rib fractures

Introduction First rib fractures are commonly reported in high velocity trauma. The neuromuscular sequelae that can ensue, not the physical disruption of the rib, necessitate thorough evaluation for such injuries. Methods We describe a case of a patient who sustained bilateral rib fractures following low-energy trauma.

Mechanism Elucidation of High-Pressure Generation in Cellular Metal at High-Velocity Impact

Cellular metals exhibit diverse properties, depending on their geometries and base materials. This study investigated the mechanism of high-pressure generation during the high-velocity impact of unidirectional cellular (UniPore) materials. Cubic UniPore copper samples were mounted on a projectile and subjected to impact loading using a powder gun to induce direct impact of samples. The specimens exhibited a unique phenomenon of high-pressure generation near the pores during compression. We elucidate the mechanism of the high-pressure phenomenon and discuss the pore geometries that contribute to the generation of high pressures.

Dry Sliding Wear and High-Velocity Impact Behaviour of Spark Plasma Sintered Ti-Ni Binary Alloys

This work investigated the dry sliding wear behaviour of spark plasma sintered (SPSed) Ti-Ni binary alloys produced at varying nickel content with alloy steel ball as the counterface material, at room temperature under varied applied normal loads. Finite element modeling was used to investigate the high-velocity impact response of the sintered alloys due to the dimensional constraint associated with SPSed samples. Microstructural analysis results revealed the presence of intermetallic phases of Ti-Ni with increasing nickel content. The best wear resistance ranging from 0.25 x 10-3 mm3/Nm to 0.22 x 10-3 mm3/Nm across all applied loads was obtained in Ti-6Ni alloy. This was attributed to the compaction of the protective triboxide and carbide layers on the surface of the sample. Oxidative and wear by adhesion were observed at low applied normal load while at high loads the prevalent wear mechanism was abrasive with reduced influence of oxidative and adhesive wear. Finite element analysis results also showed that Ti-6Ni alloy possessed the optimum combination of absorbed energy and ductility to reduce the possibility of brittle failure under impact loading. Keywords: Ti-Ni binary alloys; Spark plasma sintering; Dry sliding wear; High-velocity impact; Finite element analysis.