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  • 1
    Online Resource
    Online Resource
    MDPI AG ; 2023
    In:  Bioengineering Vol. 10, No. 5 ( 2023-04-25), p. 515-
    In: Bioengineering, MDPI AG, Vol. 10, No. 5 ( 2023-04-25), p. 515-
    Abstract: Multiscale techniques, namely homogenization, result in significant computational time savings in the analysis of complex structures such as lattice structures, as in many cases it is inefficient to model a periodic structure in full detail in its entire domain. The elastic and plastic properties of two TPMS-based cellular structures, the gyroid, and the primitive surface are studied in this work through numerical homogenization. The study enabled the development of material laws for the homogenized Young’s modulus and homogenized yield stress, which correlated well with experimental data from the literature. It is possible to use the developed material laws to run optimization analyses and develop optimized functionally graded structures for structural applications or reduced stress shielding in bio-applications. Thus, this work presents a study case of a functionally graded optimized femoral stem where it was shown that the porous femoral stem built with Ti-6Al-4V can minimize stress shielding while maintaining the necessary load-bearing capacity. It was shown that the stiffness of cementless femoral stem implant with a graded gyroid foam presents stiffness that is comparable to that of trabecular bone. Moreover, the maximum stress in the implant is lower than the maximum stress in trabecular bone.
    Type of Medium: Online Resource
    ISSN: 2306-5354
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2746191-9
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  • 2
    In: Applied Sciences, MDPI AG, Vol. 13, No. 6 ( 2023-03-16), p. 3802-
    Abstract: An anterior cruciate ligament (ACL) tear is a severe sports injury that often occurs in young athletes. Besides the strong cumulative evidence on noncontact ACL tears, the injury mechanism (especially the contribution of external rotation) is still not well understood. The present work aims to evaluate which knee kinetics result in higher ACL stress and strain. A finite element model of the ACL was developed with a detailed geometry; the two distinct bundles (anteromedial and posterolateral) and the surrounding connective tissue were modelled based on medical anatomic measures and images. The model was validated using computational and cadaveric external data. Sixteen simulations were performed using different combinations of moments and axial loads applied to the knee model as boundary conditions. The results demonstrated that the peak stress (11.00 MPa) and strain (0.048) occurred at the midportion of the anteromedial bundle with the higher values being obtained under a combined knee valgus, flexion, tibial external rotation and high axial load. Anterior load showed low sensitivity in ACL stress and strain peaks. The tibial external rotation showed a higher contribution to the peak ACL stress and strain as compared to internal rotation. These results reinforce the role of axial load and highlight the importance of external rotation on ACL stress and strain, which may be suggestive of the ACL tear mechanism. The role of external rotation is often neglected and should be further explored in future cadaveric and experimental studies. The findings of this study provide data-driven insights to optimize the indications for prevention, diagnosis and treatment of ACL injuries in clinical practice and contribute to raising awareness of the injury mechanism among all relevant stakeholders.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704225-X
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  • 3
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2021
    In:  Annals of Biomedical Engineering Vol. 49, No. 2 ( 2021-02), p. 871-884
    In: Annals of Biomedical Engineering, Springer Science and Business Media LLC, Vol. 49, No. 2 ( 2021-02), p. 871-884
    Type of Medium: Online Resource
    ISSN: 0090-6964 , 1573-9686
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 1477155-X
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  • 4
    Online Resource
    Online Resource
    Wiley ; 2020
    In:  International Journal for Numerical Methods in Biomedical Engineering Vol. 36, No. 11 ( 2020-11)
    In: International Journal for Numerical Methods in Biomedical Engineering, Wiley, Vol. 36, No. 11 ( 2020-11)
    Abstract: Angiogenesis, the development of new blood capillaries, is crucial for the wound healing process. This biological process allows the proper blood supply to the tissue, essential for cell proliferation and viability. Several biological factors modulate angiogenesis, however the vascular endothelial growth factor (VEGF) is the main one. Given the complexity of angiogenesis, in the last years, computational modelling aroused the interest of scientists since it allows to model this process with different, more economic and faster methodologies, comparatively to experimental approaches. In this work, a mathematical model motivated by the analysis of the effect of VEGF diffusion gradient in endothelial cell migration is presented. This is the process that allows capillary formation and it is essential for angiogenesis. The proposed mathematical model is combined with the Radial Point Interpolation Method, being the area discretized considering an unorganized nodal cloud and a background mesh of integration points, without predefined relations. The nodal connectivity was achieved using the “influence‐domain” approach. The interpolation functions were constructed using the Radial Point Interpolators techniques. This method combines a radial basis functions with a polynomial functions to obtain the approximation. This preliminary work does not account for the whole complexity of cell and tissue biology, and numerical results are presented for an idealised two‐dimensional setting. Nevertheless, the developed RPIM software is a valid numerical tool that can be adjusted to biological problems and may also be able to complement the biological and medical subjects.
    Type of Medium: Online Resource
    ISSN: 2040-7939 , 2040-7947
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2540968-2
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  • 5
    In: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, SAGE Publications, Vol. 236, No. 4 ( 2022-04), p. 573-582
    Abstract: Synthetic implants were used for repair of anterior compartment prolapses, which can be caused by direct trauma resulting in damaged pelvic structures. The mechanical properties of these implants may cause complications, namely erosion of the mesh through the vagina. In this study, we evaluated, by modeling, the behavior of implants, during Valsalva maneuver, used to replace damaged uterosacral ligaments (USLs), mimicking a sacrocolpopexy repair. For this purpose, two synthetic implants (A, for prolapse repair and B, for Hernia repair) were uniaxially tested, and the mechanical properties obtained were incorporated in the computational models of the implants. The computational model for the implant was incorporated into the model of the female pelvic cavity, in order to mimic the USLs after its total rupture and with 90% and 50% impairment. The total rupture and impairments of the USLs, caused a variation of the supero-inferior displacement and displacement magnitude of the vagina, with higher values for the total rupture. With total rupture of the USLs, when compared to healthy USLs, supero-inferior displacement and displacement magnitude of the vagina increased by 4.98 mm (7.69 mm vs 12.67 mm) and 6.62 mm (9.38 mm vs 16.00 mm), respectively. After implantation (A and B) a reduction of the supero-inferior displacements of the anterior vaginal wall occurred, to values found in the case of the model without any impairment or rupture of the ligaments. The simulation was able to mimic the biomechanical response of the USLs, in response to different implants stiffnesses, which can be used in the development of novel meshes.
    Type of Medium: Online Resource
    ISSN: 0954-4119 , 2041-3033
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2032763-8
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  • 6
    Online Resource
    Online Resource
    SAGE Publications ; 2018
    In:  Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine Vol. 232, No. 3 ( 2018-03), p. 257-270
    In: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, SAGE Publications, Vol. 232, No. 3 ( 2018-03), p. 257-270
    Abstract: This work has the objective to compare the mechanical behaviour of a brain impact using an alternative numerical meshless technique. Thus, a discrete geometrical model of a brain was constructed using medical images. This technique allows to achieve a discretization with realistic geometry, allowing to define locally the mechanical properties according to the medical images colour scale. After defining the discrete geometrical model of the brain, the essential and natural boundary conditions were imposed to reproduce a sudden impact force. The analysis was performed using the finite element analysis and the radial point interpolation method, an advanced discretization technique. The results of both techniques are compared. When compared with the finite element analysis, it was verified that meshless methods possess a higher convergence rate and that they are capable of producing smoother variable fields.
    Type of Medium: Online Resource
    ISSN: 0954-4119 , 2041-3033
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2018
    detail.hit.zdb_id: 2032763-8
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  • 7
    Online Resource
    Online Resource
    Elsevier BV ; 2018
    In:  Journal of Theoretical Biology Vol. 459 ( 2018-12), p. 1-17
    In: Journal of Theoretical Biology, Elsevier BV, Vol. 459 ( 2018-12), p. 1-17
    Type of Medium: Online Resource
    ISSN: 0022-5193
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2018
    detail.hit.zdb_id: 1470953-3
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    Informa UK Limited ; 2013
    In:  Computer Methods in Biomechanics and Biomedical Engineering Vol. 16, No. 11 ( 2013-11), p. 1170-1184
    In: Computer Methods in Biomechanics and Biomedical Engineering, Informa UK Limited, Vol. 16, No. 11 ( 2013-11), p. 1170-1184
    Type of Medium: Online Resource
    ISSN: 1025-5842 , 1476-8259
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 2013
    detail.hit.zdb_id: 2049175-X
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  • 9
    In: Procedia IUTAM, Elsevier BV, Vol. 24 ( 2017), p. 30-37
    Type of Medium: Online Resource
    ISSN: 2210-9838
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2017
    detail.hit.zdb_id: 2590701-3
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  • 10
    Online Resource
    Online Resource
    Politechnika Wroclawska Oficyna Wydawnicza ; 2020
    In:  Acta of Bioengineering and Biomechanics Vol. 22, No. 3 ( 2020)
    In: Acta of Bioengineering and Biomechanics, Politechnika Wroclawska Oficyna Wydawnicza, Vol. 22, No. 3 ( 2020)
    Abstract: Purpose: Bone is a hierarchical material that can be characterized from the microscale to macroscale. Multiscale models make it possible to study bone remodeling, inducing bone adaptation by using information of bone multiple scales. This work proposes a computationally efficient homogenization methodology useful for multiscale analysis. This technique is capable to define the homogenized microscale mechanical properties of the trabecular bone highly heterogeneous medium. Methods: In this work, a morphology - based fabric tensor and a set of anisotropic phenomenological laws for bone tissue was used, in order to define the bone micro-scale mechanical properties. To validate the developed methodology, several examples were performed in order to analyze its numerical behavior. Thus, trabecular bone and fabricated benchmarks patches (representing special cases of trabecular bone morphologies) were analyzed under compression. Results: The results show that the developed technique is robust and capable to provide a consistent material homogenization, indicating that the homogeneous models were capable to accurately reproduce the micro-scale patch mechanical behavior. Conclusions: The developed method has shown to be robust, computationally less demanding and enabling the authors to obtain close results when comparing the heterogeneous models with equivalent homogenized models. Therefore, it is capable to accurately predict the micro-scale patch mechanical behavior in a fraction of the time required by classic homogenization techniques.
    Type of Medium: Online Resource
    ISSN: 1509-409X , 1509-409X
    Language: English
    Publisher: Politechnika Wroclawska Oficyna Wydawnicza
    Publication Date: 2020
    detail.hit.zdb_id: 2559094-7
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