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| 2. |
- Börlin, Niclas, 1968-, et al.
(författare)
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The threaded dental implant as a reference object for image alignment
- 2001
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1025-5842 .- 1476-8259. ; 4:5, s. 421-431
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method that uses the threaded dental implant as a reference object for the inter-image alignment necessary for digital subtraction radiography. The implant is furthermore used to define a measurement coordinate system and to automate the placement of reference areas used for contrast correction. The method is intended for studies of diffuse bone density changes in the vicinity of the implant. The method is shown to be insensitive to large variations in exposure time and geometry, and is together with the contrast correction method of Ruttimann et al., able to detect clinically invisible simulated bone density changes.
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| 3. |
- Carlsson, Peter, 1950-, et al.
(författare)
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Numerical Simulation of Cross Country Skiing
- 2011
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1025-5842 .- 1476-8259. ; 14:8, s. 741-746
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Tidskriftsartikel (refereegranskat)abstract
- A program for numerical simulation of a whole ski race, from start to finish, is developed in MATLAB. The track ismodelled by a set of cubical splines in two dimensions and can be used to simulate a track in a closed loop or with the startand finish at different locations. The forces considered in the simulations are gravitational force, normal force between snowand skis, drag force from the wind, frictional force between snow and ski and driving force from the skier. The differentialequations of motion are solved from start to finish with the Runge–Kutta method. Different wind situations during the racecan be modelled, as well as different glide conditions on different parts of the track. It is also possible to vary the availablepower during the race. The simulation program’s output is the total time of the race, together with the forces and speedduring different parts of the race and intermediate times at selected points. Some preliminary simulations are also presented.
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| 4. |
- Corrales, M. A., et al.
(författare)
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Methodology to geometrically age human body models to average and subject-specific anthropometrics, demonstrated using a small stature female model assessed in a side impact
- 2023
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1476-8259 .- 1025-5842. ; 26:10, s. 1208-1219
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Tidskriftsartikel (refereegranskat)abstract
- The aged population has been associated with an increased risk of injury in car-crash, creating a critical need for improved assessment of safety systems. Finite element human body models (HBMs) have been proposed, but require representative geometry of the aged population and high mesh quality. A new hybrid Morphing-CAD methodology was applied to a 26-year-old (YO) 5th percentile female model to create average 75YO and subject-specific 86YO HBMs. The method achieved accurate morphing targets while retaining high mesh quality. The three HBMs were integrated into a side sled impact test demonstrating similar kinematic response but differing rib fracture patterns.
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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- 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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| 9. |
- Gras, Laure-Lise, 1985, et al.
(författare)
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The non-linear response of a muscle in transverse compression: Assessment of geometry influence using a finite element model
- 2012
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Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - 1476-8259 .- 1025-5842. ; 15:1, s. 13-21
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Tidskriftsartikel (refereegranskat)abstract
- Most recent finite element models that represent muscles are generic or subject-specific models that use complex, constitutive laws. Identification of the parameters of such complex, constitutive laws could be an important limit for subject-specific approaches. The aim of this study was to assess the possibility of modelling muscle behaviour in compression with a parametric model and a simple, constitutive law. A quasi-static compression test was performed on the muscles of dogs. A parametric finite element model was designed using a linear, elastic, constitutive law. A multi-variate analysis was performed to assess the effects of geometry on muscle response. An inverse method was used to define Young's modulus. The non-linear response of the muscles was obtained using a subject-specific geometry and a linear elastic law. Thus, a simple muscle model can be used to have a bio-faithful, biomechanical response
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| 10. |
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