| 1. |
- Cronskär, Marie
(författare)
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Combined finite element and multibody musculoskeletal investigation of a fractured clavicle with reconstruction plate
- 2015
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1025-5842 .- 1476-8259. ; 18:7, s. 740-748
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses the evaluation of clavicle fixation devices, by means of computational models. The aim was to developa method for comparison of stress distribution in various fixation devices, to determine whether the use of multibodymusculoskeletal input in such model is applicable and to report the approach. The focus was on realistic loading and themotivation for the work is that the treatment can be enhanced by a better understanding of the loading of the clavicle andfixation device. The method can be used to confirm the strength of customised plates, for optimisation of new plates and tocomplement experimental studies. A finite element (FE) mesh of the clavicle geometry was created from computedtomography data and imported into the FE solver where the model was subjected to muscle forces and other boundaryconditions from a multibody musculoskeletal model performing a typical activity of daily life. A reconstruction plate andscrews were also imported into the model. The combination models returned stresses and displacements of plausiblemagnitudes in all included parts and the result, upon further development and validation, may serve as a design guideline forimproved clavicle fixation.
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| 2. |
- Cui, Zhao Ying, et al.
(författare)
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On the assessment of bridging vein rupture associated acute subdural hematoma through finite element analysis
- 2017
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Taylor & Francis. - 1025-5842 .- 1476-8259. ; 20:5, s. 530-539
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Tidskriftsartikel (refereegranskat)abstract
- Acute subdural hematoma (ASDH) is a type of intracranial haemorrhage following head impact, with high mortality rates. Bridging vein (BV) rupture is a major cause of ASDH, which is why a biofidelic representation of BVs in finite element (FE) head models is essential for the successful prediction of ASDH. We investigated the mechanical behavior of BVs in the KTH FE head model. First, a sensitivity study quantified the effect of loading conditions and mechanical properties on BV strain. It was found that the peak rotational velocity and acceleration and pulse duration have a pronounced effect on the BV strains. Both Young's modulus and diameter are also negatively correlated with the BV strains. A normalized multiple linear regression model using Young's modulus, outer diameter and peak rotational velocity to predict the BV strain yields an adjusted -value of 0.81. Secondly, cadaver head impact experiments were simulated with varying sets of mechanical properties, upon which the amount of successful BV rupture predictions was evaluated. The success rate fluctuated between 67 and 75%. To further increase the predictive capability of FE head models w.r.t. BV rupture, future work should be directed towards improvement of the BV representation, both geometrically and mechanically.
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| 3. |
- Diczfalusy, Elin, et al.
(författare)
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A diffusion tensor-based finite element model of microdialysis in the deep brain
- 2015
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Taylor & Francis. - 1025-5842 .- 1476-8259. ; 18:2, s. 201-212
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Tidskriftsartikel (refereegranskat)abstract
- Microdialysis of the basal ganglia was recently used to study neurotransmitter levels in relation to deep brain stimulation. In order to estimate the anatomical origin of the obtained data, the maximum tissue volume of influence (TVImax) for a microdialysis catheter was simulated using the finite element method. This study investigates the impact of brain heterogeneity and anisotropy on the TVImax using diffusion tensor imaging (DTI) to create a second-order tensor model of the basal ganglia. Descriptive statistics showed that the maximum migration distance for neurotransmitters varied by up to 55% (n = 98,444) for DTI-based simulations compared with an isotropic reference model, and the anisotropy differed between different targets in accordance with theory. The size of the TVImax was relevant in relation to the size of the anatomical structures of interest, and local tissue properties should be accounted for when relating microdialysis data to their anatomical targets.
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| 4. |
- Gade, Jan-Lucas, et al.
(författare)
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An in vivo parameter identification method for arteries : numerical validation for the human abdominal aorta
- 2019
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Taylor & Francis. - 1025-5842 .- 1476-8259. ; , s. 426-441
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Tidskriftsartikel (refereegranskat)abstract
- A method for identifying mechanical properties of arterial tissue in vivo is proposed in this paper and it is numerically validated for the human abdominal aorta. Supplied with pressure-radius data, the method determines six parameters representing relevant mechanical properties of an artery. In order to validate the method, 22 finite element arteries are created using published data for the human abdominal aorta. With these in silico abdominal aortas, which serve as mock experiments with exactly known material properties and boundary conditions, pressure-radius data sets are generated and the mechanical properties are identified using the proposed parameter identification method. By comparing the identified and pre-defined parameters, the method is quantitatively validated. For healthy abdominal aortas, the parameters show good agreement for the material constant associated with elastin and the radius of the stress-free state over a large range of values. Slightly larger discrepancies occur for the material constants associated with collagen, and the largest relative difference is obtained for the in situ axial prestretch. For pathological abdominal aortas incorrect parameters are identified, but the identification method reveals the presence of diseased aortas. The numerical validation indicates that the proposed parameter identification method is able to identify adequate parameters for healthy abdominal aortas and reveals pathological aortas from in vivo-like data.
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| 5. |
- Kharmanda, G.
(författare)
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Integration of multi-objective structural optimization into cementless hip prosthesis design : Improved Austin-Moore model
- 2016
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1025-5842 .- 1476-8259. ; 19:14, s. 1557-1566
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Tidskriftsartikel (refereegranskat)abstract
- A new strategy of multi-objective structural optimization is integrated into Austin-Moore prosthesis in order to improve its performance. The new resulting model is so-called Improved Austin-Moore. The topology optimization is considered as a conceptual design stage to sketch several kinds of hollow stems according to the daily loading cases. The shape optimization presents the detailed design stage considering several objectives. Here, A new multiplicative formulation is proposed as a performance scale in order to define the best compromise between several requirements. Numerical applications on 2D and 3D problems are carried out to show the advantages of the proposed model.
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| 6. |
- Khayyeri, Hanifeh, et al.
(författare)
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Corroboration of computational models for mechanoregulated stem cell differentiation
- 2015
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1025-5842 .- 1476-8259. ; 18:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Do computational models contribute to progress in mechanobiology? Jacobs and Kelly (in Advances on Modelling in Tissue Engineering, p. 1–14, 2011) suggest that they do, but at the same time propose a limitation in the form of the ‘paradox of validation’, whereby the information needed to validate mechanoregulation theories obviates the need for them in the first place. In this article, the corroboration of theories describing mechanoregulation of tissue differentiation is reviewed. Considering the falsifiability of computational models derived using the theories as a measure of their predictive power, it is shown that the predictive power of some theories is poor and that models based on these theories fall into the ‘paradox of validation’. Week theories for any phenomenon would succumb to such a paradox. We argue that mechanobiology needs theories that can have more potentially falsifying experiments and that perhaps the discipline does suffer from theories that are a priori designed to minimise falsifiability. However, several theories do have predictive power beyond the data used to validate them, so a paradox of validation should disappear as the subject develops.
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| 7. |
- Lindberg, Gustav, et al.
(författare)
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A two-dimensional model for stress driven diffusion in bone tissue.
- 2015
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1025-5842 .- 1476-8259. ; 18:5, s. 457-467
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Tidskriftsartikel (refereegranskat)abstract
- The growth and resorption of bone are governed by interaction between several cells such as bone-forming osteoblasts, osteocytes, lining cells and bone-resorbing osteoclasts. The cells considered in this study reside in the periosteum. Furthermore, they are believed to be activated by certain substances to initiate bone growth. This study focuses on the role that stress driven diffusion plays in the transport of these substances from the medullary cavity to the periosteum. Calculations of stress driven diffusion are performed under steady state conditions using a finite element method with the concentration of nutrients in the cambium layer of the periosteum obtained for different choices of load frequencies. The results are compared with experimental findings, suggesting that increased bone growth occurs in the neighbourhood of relatively high nutrient concentration.
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| 8. |
- Wang, F., et al.
(författare)
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Numerical investigations of rib fracture failure models in different dynamic loading conditions
- 2016
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1476-8259 .- 1025-5842. ; 19:5, s. 527-537
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Tidskriftsartikel (refereegranskat)abstract
- Rib fracture is one of the most common thoracic injuries in vehicle traffic accidents that can result in fatalities associated with seriously injured internal organs. A failure model is critical when modelling rib fracture to predict such injuries. Different rib failure models have been proposed in prediction of thorax injuries. However, the biofidelity of the fracture failure models when varying the loading conditions and the effects of a rib fracture failure model on prediction of thoracic injuries have been studied only to a limited extent. Therefore, this study aimed to investigate the effects of three rib failure models on prediction of thoracic injuries using a previously validated finite element model of the human thorax. The performance and biofidelity of each rib failure model were first evaluated by modelling rib responses to different loading conditions in two experimental configurations: (1) the three-point bending on the specimen taken from rib and (2) the anterior–posterior dynamic loading to an entire bony part of the rib. Furthermore, the simulation of the rib failure behaviour in the frontal impact to an entire thorax was conducted at varying velocities and the effects of the failure models were analysed with respect to the severity of rib cage damages. Simulation results demonstrated that the responses of the thorax model are similar to the general trends of the rib fracture responses reported in the experimental literature. However, they also indicated that the accuracy of the rib fracture prediction using a given failure model varies for different loading conditions.
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