ABSTRACT
Displaced fractures of the glenoid require surgical fixation. This poses multiple problems, including a difficult approach and achieving adequate reduction with current implants. We provide a surgical technical tip for fixing scapula neck and glenoid rim fractures with an Acu-Loc distal radius plate (Acumed, Weyhill, UK), illustrated with two recent case reports. Here, we present two cases of a 58-year-old female and a 51-year-old male presenting to a hospital following a fall, both sustaining an isolated right glenoid intra-articular fracture evident on plain radiographs. CT scans revealed a displaced and fragmented glenoid surface. A reverse Judet posterior approach facilitated exposure to enable the reduction of the glenoid, an uncommon approach. Current plate designs provide surgeons with limited options to fix complex fractures of the scapula and were not suitable here. The lateral scapula border and inferior glenoid have a similar anatomical shape to the distal radius. An Acu-Loc locking distal radius plate with a radial styloid plate was trialled and provided a good reduction to the fragmented glenoid. A distal radius plate can be a useful option to consider in complex scapula neck and glenoid rim fractures. A better understanding of glenoid shape will facilitate the further development of orthopaedic implants. Familiarity with various surgical approaches is needed to operate on these complex fractures.
ABSTRACT
Electric discharge machining is an essential modern manufacturing process employed to machine porous sintered metals. The sintered 316L porous stainless steel (PSS) components are widely used in diverse engineering domains, as interconnected pores are present. The PSS material has excellent lightweight and damping properties and superior mechanical and metallurgical properties. However, conventional machining techniques are not suitable for porous metals machining. Such techniques tend to block the micro-pores, resulting in a decrease in porous materials' breathability. Thus, the EDM process is an effective technique for porous metal machining. The input process parameters selected in this study are peak current (Ip), pulse on time (Ton), voltage (V), flushing pressure (fp), and porosity. The response parameters selected are material removal rate (MRR) and tool wear rate (TWR). The present work aims to obtain optimum machining process parameters in the EDM of porous sintered SS316L using two meta-heuristic optimization techniques, i.e., Teaching Learning-Based Optimization (TLBO) and Particle Swarm Optimization (PSO) algorithms, to maximize the MRR and minimize the TWR values. In the case of PSS having a 12.60% porosity value, PSO and TLBO algorithms give same optimum machining parameters. However, for PSS having an 18.85% porosity value, the PSO algorithm improves by about 5.25% in MRR and by 5.63% in TWR over the TLBO. In the case of PSS having a 31.11% porosity value, the PSO algorithm improves about 3.73% in MRR and 6.46% in TWR over the TLBO. The PSO algorithm is found to be consistent and to converge more quickly, taking minimal computational time and effort compared to the TLBO algorithm. The present study's findings contribute valuable information in regulating the EDM performance in machining porous SS316L.
ABSTRACT
High-performance polymer composites are being increasingly favored for structural applications. For this purpose, efforts are being focused on exploring the potential of high-performance thermoplastics and thermosets. Cyanate ester (CE) resin is a special thermoset that can be used at up to 400 °C without any considerable degradation; however, its tribological properties are not at the adequate level. Hence, it is needed to use this polymer in composite form with the fibrous/particulate reinforcement to impart better tribological properties and mechanical strength via a strong fiber-matrix interface. Carbon fiber/fabrics are at the forefront as reinforcement for specialty polymers. The tribological and tensile properties of cyanate ester (CE) composites-filled graphite, polytetrafluoroethylene (PTFE), and MoS2 micron-sized fillers reinforced with carbon fibers (CF) are investigated experimentally in a block-on-ring setup at 100 N, for 10 h, and with a sliding distance of approximately 10,000 m, against a hardened polished 100Cr6 steel shaft and diamond-like-coated (DLC) 100Cr6 steel shaft. The tribological properties of the composites including the coefficient of friction and specific wear rate are enhanced especially with the incorporation of graphite fillers. The friction coefficient and wear rate of the graphite-based composite was decreased significantly at 5 wt.% of graphite concentration. Further, at the same concentration, the graphite-based composite showed superior tensile properties as compared to the reference system owing to better dispersion and adhesion between the fibers and matrix. Tensile tests are performed to characterize the fiber-matrix interfacial adhesion and other strength properties.
