liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Edlund, Ulf
Publications (10 of 16) Show all publications
Fahlgren, A., Johansson, L., Edlund, U. & Aspenberg, P. (2012). Direct ex vivo measurement of the fluid permeability of loose scar tissue. Acta of Bioengineering and Biomechanics, 14(2), 47-51
Open this publication in new window or tab >>Direct ex vivo measurement of the fluid permeability of loose scar tissue
2012 (English)In: Acta of Bioengineering and Biomechanics, ISSN 1509-409X, Vol. 14, no 2, p. 47-51Article in journal (Refereed) Published
Abstract [en]

Fluid flow is important in many biomechanical models, but there is a lack of experimental data that quantifies soft tissue permeability. We measured the tissue permeability in fibrous soft tissue, using a novel technique to obtain specimens by allowing soft tissue to grow into coralline hydroxyapatite scaffoldings implanted between the abdominal muscle layers of rats.

Place, publisher, year, edition, pages
Wroclaw, Poland: Wroclaw University of Technology, 2012
Keywords
permeability, Darcys law, soft tissue, hydraulic conductivity
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-93986 (URN)10.5277/abb120206 (DOI)000318777500006 ()
Available from: 2013-06-13 Created: 2013-06-13 Last updated: 2014-02-27Bibliographically approved
Johansson, L., Edlund, U., Fahlgren, A. & Aspenberg, P. (2011). Fluid-induced osteolysis: modelling and experiments. COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING, 14(4), 305-318
Open this publication in new window or tab >>Fluid-induced osteolysis: modelling and experiments
2011 (English)In: COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING, ISSN 1025-5842, Vol. 14, no 4, p. 305-318Article in journal (Refereed) Published
Abstract [en]

A model to calculate bone resorption driven by fluid flow at the bone-soft tissue interface is developed and used as a basis for computer calculations, which are compared to experiments where bone is subjected to fluid flow in a rat model. Previous models for bone remodelling calculations have been based on the state of stress, strain or energy density of the bone tissue as the stimulus for remodelling. We believe that there is experimental support for an additional pathway where an increase in the amount of the cells directly involved in bone removal, the osteoclasts, is caused by fluid pressure, flow velocity or other parameters related to fluid flow at the bone-soft tissue interface, resulting in bone resorption.

Place, publisher, year, edition, pages
Taylor and Francis, 2011
Keywords
bone resorption, theory of mixtures, experimental model, finite element method
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-67561 (URN)10.1080/10255842.2010.484808 (DOI)000288951800001 ()
Available from: 2011-04-18 Created: 2011-04-18 Last updated: 2012-03-22
Schmidt, P. & Edlund, U. (2010). A finite element method for failure analysis of adhesively bonded structures. International Journal of Adhesion and Adhesives, 30(8), 665-681
Open this publication in new window or tab >>A finite element method for failure analysis of adhesively bonded structures
2010 (English)In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, Vol. 30, no 8, p. 665-681Article in journal (Refereed) Published
Abstract [en]

The solid bodies constituting the adhesively bonded joint, i.e. the adhesive and the adherends, are treated as material surfaces. The result can be regarded as a structural element model of the compound joint. The adhesive is modelled as a softening material due to local material damage. As a consequence, the propagation of a crack front in the adhesive layer can be followed, and the failure load of the structure becomes a computational result. A one-parameter viscous regularization of the softening adhesive material law is used in order to improve the numerical behavior. Several applications are presented

Place, publisher, year, edition, pages
Elsevier, 2010
Keywords
Adhesively bonded joint, Finite element, Damage mechanics, Failure simulation, Viscous regularization
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-60646 (URN)10.1016/j.ijadhadh.2010.05.012 (DOI)000283963400001 ()
Projects
NFFP-KEKS, Cost Effective Composite Structures
Available from: 2010-10-21 Created: 2010-10-21 Last updated: 2012-01-20
Fahlgren, A., Bostrom, M. P., Yang, X., Johansson, L., Edlund, U., Agholme, F. & Aspenberg, P. (2010). Fluid pressure and flow as a cause of bone resorption. Acta Orthopaedica, 81(4), 508-516
Open this publication in new window or tab >>Fluid pressure and flow as a cause of bone resorption
Show others...
2010 (English)In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 81, no 4, p. 508-516Article in journal (Refereed) Published
Abstract [en]

Background Unstable implants in bone become surrounded by an osteolytic zone. This is seen around loose screws, for example, but may also contribute to prosthetic loosening. Previous animal studies have shown that such zones can be induced by fluctuations in fluid pressure or flow, caused by implant instability. Method To understand the roles of pressure and flow, we describe the 3-dimensional distribution of osteolytic lesions in response to fluid pressure and flow in a previously reported rat model of aseptic loosening. 50 rats had a piston inserted in the proximal tibia, designed to produce 20 local spikes in fluid pressure of a clinically relevant magnitude (700 mmHg) twice a day. The spikes lasted for about 0.3 seconds. After 2 weeks, the pressure was measured in vivo, and the osteolytic lesions induced were studied using micro-CT scans. Results Most bone resorption occurred at pre-existing cavities within the bone in the periphery around the pressurized region, and not under the piston. This region is likely to have a higher fluid flow and less pressure than the area just beneath the piston. The velocity of fluid flow was estimated to be very high (roughly 20 mm/s). Interpretation The localization of the resorptive lesions suggests that high-velocity fluid flow is important for bone resorption induced by instability.

Place, publisher, year, edition, pages
Taylor & Francis, 2010
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-58811 (URN)10.3109/17453674.2010.504610 (DOI)000282742300016 ()
Available from: 2010-09-02 Created: 2010-08-27 Last updated: 2017-12-12
Edlund, U., Schmidt, P. & Roguet , E. (2009). A model of an adhesively bonded joint with elastic-plastic adherends and a softening adhesive. Computer Methods in Applied Mechanics and Engineering, 198(5-8), 740-752
Open this publication in new window or tab >>A model of an adhesively bonded joint with elastic-plastic adherends and a softening adhesive
2009 (English)In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 198, no 5-8, p. 740-752Article in journal (Refereed) Published
Abstract [en]

This paper deals with the generalization of a model of an adhesively bonded joint with the aim to allow elastic-plastic adherends. In the model of the joint that we extend, the thinness of the bodies and the low Youngs modulus of the adhesive were used to obtain a simplified model where the parts are described as material surfaces. We formulate an elastic-plastic material model with isotropic hardening expressed in the generalized stress and strain measures used for the surface description of the joint. The finite element formulation and the numerical treatment of the constitutive law are discussed. Numerical results showing the accuracy of the proposed treatment of the adherends are presented. Two failure load computations, using a softening material model for the adhesive, are presented and compared with experiments. The results show the importance of taking into account potential plastic deformations in the adherends in failure load computations.

Keywords
Adhesively bonded joint, Elastic-plastic adherends, Finite element, Damage mechanics
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-16974 (URN)10.1016/j.cma.2008.10.015 (DOI)
Available from: 2009-03-01 Created: 2009-02-27 Last updated: 2017-12-13
Schmidt, P. & Edlund, U. (2009). A Multi-Layer Finite Element Method for Analysis of Adhesively Bonded Composite Laminates with Interlaminar Failure.: NFFP-KEKS Report WP2.2: Deliverables 2.2-3. Linköping
Open this publication in new window or tab >>A Multi-Layer Finite Element Method for Analysis of Adhesively Bonded Composite Laminates with Interlaminar Failure.: NFFP-KEKS Report WP2.2: Deliverables 2.2-3
2009 (English)Report (Other academic)
Place, publisher, year, edition, pages
Linköping: , 2009
Series
NFFP-KEKS Reports ; Report WP2.2: Deliverables 2.2-3
Keywords
Adhesive Joints, Multi-Layer, Finite Element, Interlaminar Failure, Damage Mechanics
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-18818 (URN)
Projects
NFFP - Cost Effective Composite Structures (KEKS)
Note
KEKS = KostnadsEffektiva KompositStrukturerAvailable from: 2009-06-04 Created: 2009-06-04 Last updated: 2017-04-19Bibliographically approved
Johansson, L., Edlund, U., Fahlgren, A. & Aspenberg, P. (2009). Bone Resorption Induced by Fluid Flow. Journal of Biomechanical Engineering, 131(9), 094505-1-094505-5
Open this publication in new window or tab >>Bone Resorption Induced by Fluid Flow
2009 (English)In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 131, no 9, p. 094505-1-094505-5Article in journal (Refereed) Published
Abstract [en]

A model where bone resorption is driven by stimulus from fluid flow is developed and used as a basis for computer simulations, which are compared with experiments. Models for bone remodeling are usually based on the state of stress, strain, or energy density of the bone tissue as the stimulus for remodeling. We believe that there is experimental support for an additional pathway, where an increase in the amount of osteoclasts, and thus osteolysis, is caused by the time history of fluid flow velocity, fluid pressure, or other parameters related to fluid flow at the bone/soft tissue interface of the porosities in the bone.

Place, publisher, year, edition, pages
ASME, 2009
Keywords
bone resorption, constitutive model
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:liu:diva-20801 (URN)10.1115/1.3194756 (DOI)
Available from: 2009-09-21 Created: 2009-09-21 Last updated: 2017-12-13
Schmidt, P. & Edlund, U. (2009). Effekten av geometriska olineariteter i limelementets ytbeskrivning: NFFP-KEKS Report WP2.2: Deliverables 2.2-5. Linköping
Open this publication in new window or tab >>Effekten av geometriska olineariteter i limelementets ytbeskrivning: NFFP-KEKS Report WP2.2: Deliverables 2.2-5
2009 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Linköping: , 2009
Series
NFFP-KEKS Reports ; Report WP2.2: Deliverables 2.2-5
Keywords
Finita Element, Limning, Geometriskt Olinjär
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:liu:diva-18820 (URN)
Projects
NFFP - KostnadsEffektiva KompositStrukturer (KEKS)
Available from: 2009-06-05 Created: 2009-06-05 Last updated: 2009-06-05Bibliographically approved
Schmidt, P. & Edlund, U. (2009). LIU-IEI-R--09/0058 - A Multi-Layer Finite Element Method for Analysis of Adhesively Bonded Composite Laminates with Interlaminar Failure. NFFP-KEKS Report WP2.2: Deliverables 2.2-3 (2009).
Open this publication in new window or tab >>LIU-IEI-R--09/0058 - A Multi-Layer Finite Element Method for Analysis of Adhesively Bonded Composite Laminates with Interlaminar Failure. NFFP-KEKS Report WP2.2: Deliverables 2.2-3 (2009)
2009 (English)Other (Other (popular science, discussion, etc.))
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-45301 (URN)80931 (Local ID)80931 (Archive number)80931 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2010-12-03
Schmidt, P. & Edlund, U. (2009). LIU-IEI-R--09/0059--SE - Parameter Identification of Adhesives and Interface Properties. NFFP-KEKS Report WP2.2: Deliverables 2.2-4 (2009).
Open this publication in new window or tab >>LIU-IEI-R--09/0059--SE - Parameter Identification of Adhesives and Interface Properties. NFFP-KEKS Report WP2.2: Deliverables 2.2-4 (2009)
2009 (English)Other (Other (popular science, discussion, etc.))
Abstract [en]

   

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-45302 (URN)80932 (Local ID)80932 (Archive number)80932 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2010-12-03
Organisations

Search in DiVA

Show all publications