TY  - JOUR
A1  - Staat, Manfred
A1  - Sponagel, Stefan
A1  - Nguyen, Nhu Huynh
T1  - Experiment and material model for soft tissue materials
JF  - Constitutive  models for rubber VI : proceedings of the sixth European Conference on Constitutive Models for Rubber, Dresden, Germany, 7 - 10 September 2009 / eds. Gert Heinrich ...
Y1  - 2010
SN  - 978-0-415-56327-7
SP  - 465
EP  - 470
PB  - CRC Press
CY  - Boca Raton [u.a.]
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Baroud, G.
A1  - Topcu, M.
A1  - Sponagel, Stefan
T1  - Soft Materials in Technology and Biology – Characteristics, Properties, and Parameter Identification
JF  - Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)
Y1  - 2008
SN  - 978-3-540-75408-4
SP  - 253
EP  - 315
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Baroud, G.
A1  - Falk, R.
A1  - Crookshank, M.
T1  - Experimental and theoretical investigation of directional permeability of human vertebral cancellous bone for cement infiltration. G. Baroud, R. Falk, M. Crookshank, S. Sponagel, T. Steffen
JF  - Journal of Biomechanics. 37 (2004), H. 2
Y1  - 2004
SN  - 0021-9290
SP  - 189
EP  - 196
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Baroud, G.
A1  - Falk, R.
A1  - Crookshank, M.
T1  - Corrigendum to “Experimental and theoretical investigation of directional permeability of human vertebral cancellous bone for cement infiltration”. Baroud, G.; Falk, R.; Crookshank, M.; Sponagel, S.; Steffen, T.
JF  - Journal of Biomechanics. 37 (2004), H. 2
Y1  - 2004
SN  - 0021-9290
SP  - 1802
ER  - 
TY  - JOUR
A1  - Kühn, Raoul-Roman
A1  - Haugner, Werner
A1  - Staat, Manfred
A1  - Sponagel, Stefan
T1  - A Two Phase Mixture Model based on Bone Observation
N2  - An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff’s law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency.
KW  - Knochen
KW  - Knochenbildung
KW  - Knochenchirugie
KW  - Strukturanalyse
KW  - Schwammknochen
KW  - Knochendichte
KW  - Wolffsches Gesetz
KW  - bone structure
KW  - bone density
KW  - Wolff's Law
KW  - cancellous bone
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Baroud, G.
A1  - Wu, J.Z.
A1  - Bohner, M
A1  - Sponagel, Stefan
A1  - Steffen, T.
T1  - How to determine the permeability for cement infiltration into osteoporotic cancellous bone
JF  - Medical Engineering & Physics. 25 (2003), H. 4
N2  - Cement augmentation is an emerging surgical procedure in which bone cement is used to infiltrate and reinforce osteoporotic vertebrae. Although this infiltration procedure has been widely applied, it is performed empirically and little is known about the flow characteristics of cement during the injection process. We present a theoretical and experimental approach to investigate the intertrabecular bone permeability during the infiltration procedure. The cement permeability was considered to be dependent on time, bone porosity, and cement viscosity in our analysis. In order to determine the time-dependent permeability, ten cancellous bone cores were harvested from osteoporotic vertebrae, infiltrated with acrylic cement at a constant flow rate, and the pressure drop across the cores during the infiltration was measured. The viscosity dependence of the permeability was determined based on published experimental data. The theoretical model for the permeability as a function of bone porosity and time was then fit to the testing data. Our findings suggest that the intertrabecular bone permeability depends strongly on time. For instance, the initial permeability (60.89 mm4/N.s) reduced to approximately 63% of its original value within 18 seconds. This study is the first to analyze cement flow through osteoporotic bone. The theoretical and experimental models provided in this paper are generic. Thus, they can be used to systematically study and optimize the infiltration process for clinical practice.
KW  - Osteoporose
KW  - Permeabilität
KW  - Viskose Strömung
KW  - Viskosität
KW  - Vertebroplastie
KW  - Cement infiltration
KW  - Vertebroplasty
KW  - Osteoporosis
KW  - Permeability
KW  - Experiment
KW  - Analysis
KW  - Viscous flow
Y1  - 2003
SN  - 1350-4533
SP  - 283
EP  - 288
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Baroud, G.
A1  - Steffen, T.
A1  - Wu, J.
T1  - Parameter identification for cement infiltration of osteoporotic bone
JF  - Poromechanics II : Proceedings of the Second Biot Conference on Poromechanics Grenoble, France 26 - 28 August 2002 / ed. by J.-L. Auriault ...
Y1  - 2002
SN  - 90-5809-394-8
SP  - 55
EP  - 58
PB  - Balkema
CY  - Lisse [u.a.]
ER  - 
TY  - PAT
A1  - Sponagel, Stefan
A1  - Wachowitz, Waldemar
T1  - Shaft seal : United States Patent 5,143,385 ; date of patent: Sep. 1, 1992 / assignee: Firma Carl Freudenberg
Y1  - 1992
N1  - Barcode: US005143385A ; Volltext über Datenbank: http://www.google.com/patents
PB  - [United States Patent and Trademark Office]
CY  - [Alexandria, VA]
ER  - 
TY  - PAT
A1  - Sponagel, Stefan
A1  - Graf, Günter
A1  - Groß, Heinz
T1  - Method for manufacturing a sealing ring : United States Patent 4,861,536 ; date of patent: Aug. 12, 1989 / assignee: Firma Carl Freudenberg. Inventors: Gunter Graf ; Heinz Gross ; Stefan Sponagel
Y1  - 1989
N1  - Barcode: US004861536A ; Volltext über Datenbank: http://www.google.com/patents
PB  - [United States Patent and Trademark Office]
CY  - [Alexandria, VA]
ER  - 
TY  - PAT
A1  - Sponagel, Stefan
A1  - Graf, Günter
A1  - Groß, Heinz
T1  - Method for the manufacture of a sealing ring with a sealing lip having hydrodynamically acting return elements : United States Patent 4,850,097 ; date of patent: Jul. 25, 1989 / assignee: Firma Carl Freudenberg. Inventors: Gunter Graf ; Heinz Gross ; Stefan Sponagel
Y1  - 1989
N1  - Barcode: US004850097A ; Volltext über Datenbank: http://www.google.com/patents
PB  - [United States Patent and Trademark Office]
CY  - [Alexandria, VA]
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Kilthau, G.
A1  - Spies, K. H.
T1  - Sealing mechanism of lip seals
JF  - Eleventh 11th International Conference on Fluid Sealing : proceedings of the 11th Internat. Conference on Fluid Sealing, held at Cannes, France 8 - 10 April, 1987 / organised and sponsored by BHRA, the Fluid Engineering Centre. Ed. B. S. Nau
Y1  - 1987
SN  - 3-540-51383-3
N1  - International Conference on Fluid Sealing <11, 1987, Cannes>
SP  - 748
EP  - 772
PB  - Elsevier
CY  - London
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Akbay, U.
A1  - Becker, E.
T1  - Instability of plane Couette flow of viscoelastic liquids
JF  - Journal of non-Newtonian fluid mechanics. 18 (1985), H. 2
Y1  - 1985
SN  - 0377-0257
SP  - 123
EP  - 141
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Akbay, U.
A1  - Becker, E.
A1  - Krozer, S.
T1  - Instability of slow viscometric flow
JF  - Mechanics Research Communications. 7 (1980), H. 4
Y1  - 1980
SN  - 0093-6413
SP  - 199
EP  - 204
ER  - 
TY  - JOUR
A1  - Sponagel, Stefan
A1  - Adbay, U.
A1  - Becker, E.
A1  - Krozer, S.
T1  - A possible cause of viscoelastic turbulence
JF  - Rheology : proceedings of the 8th International Congress of Rheology, held in Naples, Italy, September 1 - 5, 1980 / Hrsg. von Giovanni Astarita, Vol. 2
Y1  - 1980
SN  - 0-306-40465-6
SP  - 79
EP  - 84
PB  - Plenum Pr.
CY  - New York
ER  -