Ústav mechaniky těles, mechatroniky a biomechaniky

Browse

Recent Submissions

Now showing 1 - 5 of 81
  • Thumbnail Image
    Item
    Fracture predictions in impact three-point bending test of European beech
    (Springer Nature, 2024-08-31) Kubík, Petr; Šebek, František; Hassan Vand, Mojtaba; Brabec, Martin; Tippner, Jan
    Hardwood has become widespread in European forests. The strongest factor is climate change and damage to conifers by the bark beetle. The effort to study hardwoods grows with increasing volume of applications. Therefore, European beech wood was investigated under two impact loads in two material directions, resulting in four unique combinations supplemented by the measurement of the friction coefficient. Then, it was computationally simulated to reproduce the cracking, while the material model reflected the orthotropic behaviour in elasticity, plasticity and failure. The model was coded using the user subroutine in Abaqus to initiate and propagate the crack using the element deletion. The resulting reaction forces were in good agreement with those from the experiments. Cracking was numerically simulated in three of four cases as experimentally observed, however, upon larger deflections. Therefore, the model is applicable for further investigations.
  • Thumbnail Image
    Item
    Impact of different disinfection solutions on mechanical properties of orthodontic impress silicone material
    (Brno University of Technology, Czech Academy of Sciences, 2024-05-14) Hrubanová, Anna; Thomková, Barbora; Košková, Olga; Richtrova, Michaela; Borák, Libor; Stourac, Petr; Marcián, Petr
    This study explores the influence of disinfection on silicone material used in cleft protection and orthodontic impressions. A series of uniaxial tensile tests were conducted to evaluate the mechanical properties after disinfection. Statistical analysis of stress-strain curves at various stress levels using one-way ANOVA showed no significant differences, supporting the hypothesis that disinfection does not compromise the material properties of the silicone used for the cleft protection with obturators. Additionally, the study explores the utilization of 3D printing for creating a casting mold used in the manufacturing of silicon-based products.
  • Thumbnail Image
    Item
    ASO Author Reflections: The Effect of Local Adjuvants on Cortical Bone Following Intralesional Curettage of Bone Tumors
    (SPRINGER, 2024-06-01) Apostolopoulos, Vasileios; Boháč, Petr; Marcián, Petr; Staniczková Zambo, Iva; Pazourek, Lukáš; Mahdal, Michal; Neradil, Jakub; Návrat, Tomáš; Tomáš, Tomáš
    The irregular shape of the tumor cavity in certain types of tumors poses a significant challenge in completely removing both microscopic and macroscopic tumor residues. Currently, there is no consensus regarding the choice of local adjuvant therapy for tumor treatment. Further clinical investigation is required to validate the results of this experimental study.
  • Thumbnail Image
    Item
    Biomechanical comparison of all-polyethylene total knee replacement and its metal-backed equivalent on periprosthetic tibia using the finite element method
    (BMC, 2024-02-23) Apostolopoulos, Vasileios; Boháč, Petr; Marcián, Petr; Nachtnebl, Luboš; Mahdal, Michal; Pazourek, Lukáš; Tomáš, Tomáš
    BackgroundTotal knee arthroplasty (TKA) with all-polyethylene tibial (APT) components has shown comparable survivorship and clinical outcomes to that with metal-backed tibial (MBT). Although MBT is more frequently implanted, APT equivalents are considered a low-cost variant for elderly patients. A biomechanical analysis was assumed to be suitable to compare the response of the periprosthetic tibia after implantation of TKA NexGen APT and MBT equivalent.MethodsA standardised load model was used representing the highest load achieved during level walking. The geometry and material models were created using computed tomography data. In the analysis, a material model was created that represents a patient with osteopenia.ResultsThe equivalent strain distribution in the models of cancellous bone with an APT component showed values above 1000 mu epsilon in the area below the medial tibial section, with MBT component were primarily localised in the stem tip area. For APT variants, the microstrain values in more than 80% of the volume were in the range from 300 to 1500 mu epsilon, MBT only in less than 64% of the volume.ConclusionThe effect of APT implantation on the periprosthetic tibia was shown as equal or even superior to that of MBT despite maximum strain values occurring in different locations. On the basis of the strain distribution, the state of the bone tissue was analysed to determine whether bone tissue remodelling or remodelling would occur. Following clinical validation, outcomes could eventually modify the implant selection criteria and lead to more frequent implantation of APT components.
  • Thumbnail Image
    Item
    Implant Preference and Clinical Outcomes of Patients with Staged Bilateral Total Knee Arthroplasty: All-Polyethylene and Contralateral Metal-Backed Tibial Components
    (MDPI, 2023-11-30) Nachtnebl, Luboš; Apostolopoulos, Vasileios; Mahdal, Michal; Pazourek, Lukáš; Brančík, Pavel; Valoušek, Tomáš; Boháč, Petr; Tomáš, Tomáš
    Numerous studies have compared metal-backed components (MBTs) and all-polyethylene tibial components (APTs), but none of them specifically analysed the clinical results and the overall patient preference in patients who had undergone a staged bilateral knee replacement. The purpose of this study is to compare clinical results, perceived range of motion, and overall implant preference among patients who had undergone staged bilateral knee replacement with an APT and contralateral knee replacement with MBTs. A dataset of 62 patients from a single centre who underwent staged bilateral TKA between 2009 and 2022 was selected and retrospectively analysed. Tibial component removal was performed in three knees overall, all of which had MBTs. The mean measured Knee Score (KS) of knees with APTs was 78.37 and that of contralateral knees with MBTs was 77.4. The mean measured Function (FS) of knees with APTs was 78.22, and that of contralateral knees with MBs was 76.29. The mean flexion angle of knees with APTs was 103.8 and that for knees with MBTs was 101.04 degrees. A total of 54.8% of the patients preferred the knee that received APTs over contralateral MBTs. In our cohort, TKA with an APT in one knee and an MBT in the contralateral knee recorded similar clinical results and perceived ranges of motion. Patients in general preferred the knee that received an APT over contralateral knee with an MBT.