The study investigated the dependence of the indentation load on nanomechanical properties for a gas-borided layer produced on Inconel 600-alloy. During the measurements, the indentation load range from 10 mN to 500 mN was used. Three types of tested areas, differing in the concentration of chromium, were examined. The increase in chromium concentration was accompanied by an increase in indentation hardness and Young's modulus. Simultaneously, the increase in the indentation load resulted in a decrease in the indentation hardness and Young's modulus, for each type of the tested area. The presence of the indentation size effect was analyzed using four models: Meyer's law, Hays and Kendall model, Li and Bradt model, Nix and Gao model. For all tested areas, good agreement with the Meyer's law was obtained. However, areas with a higher chromium concentration were more susceptible to indentation size effect (ISE). The proportional specimen resistance (PSR) model was used to describe the plastic-elastic behavior of the tested materials, as well as to detect the presence of ISE. It was found that the increase in chromium concentration in the tested area was accompanied by a greater tendency to elastic deformation during nanoindentation.
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http://dx.doi.org/10.3390/ma14216727 | DOI Listing |
Biomech Model Mechanobiol
January 2025
Department of Mechanical Engineering, University of Louisiana at Lafayette, Lafayette, LA, 70503, USA.
This research demonstrates a systematic curve fitting approach for acquiring parametric values of hyperelastic constitutive models for both healthy and enzymatically mediated degenerated cartilage to facilitate finite element modeling of cartilage. Several widely used phenomenological hyperelastic constitutive models were tested to adequately capture the changes in cartilage mechanics that vary with the differential/unequal abundance of matrix metalloproteinases (MMPs). Trauma and physiological conditions result in an increased production of collagenases (MMP-1) and gelatinases (MMP-9), which impacts the load-bearing ability of cartilage by significantly deteriorating its extracellular matrix (ECM).
View Article and Find Full Text PDFJ R Soc Interface
January 2025
Department of Mechanical Engineering, Imperial College London, London, UK.
Following lower limb amputation residuum skin from the lower leg is used to reconstruct the residual limb. Unlike skin on the sole of the foot (plantar skin), leg skin is not inherently load bearing. Despite this, leg skin is required to be load bearing in the prosthetic socket.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department Dental Clinical Sciences, Dalhousie University, 5981 University Avenue, Halifax, NS B3H 4R2, Canada.
The load and size of the indentation may affect the hardness value. This study investigated the effect of the indentation size on the microhardness of one resin-based composite (RBC). Metal molds 4 mm deep and 12 mm in diameter were filled with Tetric EvoCeram Bulk Fill (Ivoclar) and light-cured for 10 s using a broad-spectrum LED curing light.
View Article and Find Full Text PDFPurpose: The objective was to use cyclic tensile loading to compare the gap formation at suture site of three different suture materials to repair bovine radial meniscal tears: (1) polyglactin sutures, (2) tough adhesive puncture sealing (TAPS) sutures and (3) ultra-high molecular weight polyethylene (UHMWPE) sutures.
Methods: Twelve ex vivo bovine knees were dissected to retrieve the menisci. Complete radial tears were performed on 24 menisci, which were then separated into three groups and repaired using either pristine 2-0 polyglactin sutures, TAPS sutures (2-0 polyglactin sutures coated with adhesive chitosan/alginate hydrogels) or 2-0 UHMWPE sutures with a single stitch.
Materials (Basel)
December 2024
Institute of Physics & Optoelectronics Technology, Baoji University of Arts and Sciences, Baoji 721016, China.
CrCoNi medium-entropy alloys (MEAs), characterised by their high configurational entropies, have become a research hotspot in materials science. Recent studies have indicated that MEAs exhibit short-range order (SRO), which affects their deformation mechanisms. In this study, the micro-mechanisms of SRO within the framework of mesoscale continuum mechanics are mathematically evaluated using an advanced, non-local crystal plasticity constitutive framework.
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