TY  - JOUR
A1  - Staat, Manfred
A1  - Heitzer, M.
T1  - Limit and Shakedown Analysis for Plastic Safety of Complex Structures
JF  - Transactions of the 14th International Conference on Structural Dynamics in Reactor Technology (SMiRT-14) / Livolant, M. [ed]
Y1  - 1997
N1  - Vol. B, Paper B02/2
SP  - 33
EP  - 40
CY  - Lyon
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Vu, Duc-Khoi
T1  - Limit analysis of flaws in pressurized pipes and cylindrical vessels. Part I: Axial defects
JF  - Engineering Fracture Mechanics. 74 (2007), H. 3
Y1  - 2007
SN  - 0013-7944
SP  - 431
EP  - 450
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Vu, Duc Khoi
T1  - Limit analysis of flaws in pressurized pipes and cylindrical vessels Part II: Circumferential defects
JF  - Engineering Fracture Mechanics ; 97(2013), H. 1
N2  - Upper and lower bound theorems of limit analyses have been presented in part I of the paper. Part II starts with the finite element discretization of these theorems and demonstrates how both can be combined in a primal–dual optimization problem. This recently proposed numerical method is used to guide the development of a new class of closed-form limit loads for circumferential defects, which show that only large defects contribute to plastic collapse with a rapid loss of strength with increasing crack sizes. The formulae are compared with primal–dual FEM limit analyses and with burst tests. Even closer predictions are obtained with iterative limit load solutions for the von Mises yield function and for the Tresca yield function. Pressure loading of the faces of interior cracks in thick pipes reduces the collapse load of circumferential defects more than for axial flaws. Axial defects have been treated in part I of the paper.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.engfracmech.2012.05.017
SN  - 0013-7944
VL  - 97
SP  - 314
EP  - 333
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bhattarai, Aroj
A1  - May, Charlotte Anabell
A1  - Staat, Manfred
A1  - Kowalczyk, Wojciech
A1  - Tran, Thanh Ngoc
T1  - Layer-specific damage modeling of porcine large intestine under biaxial tension
JF  - Bioengineering
N2  - The mechanical behavior of the large intestine beyond the ultimate stress has never been investigated. Stretching beyond the ultimate stress may drastically impair the tissue microstructure, which consequently weakens its healthy state functions of absorption, temporary storage, and transportation for defecation. Due to closely similar microstructure and function with humans, biaxial tensile experiments on the porcine large intestine have been performed in this study. In this paper, we report hyperelastic characterization of the large intestine based on experiments in 102 specimens. We also report the theoretical analysis of the experimental results, including an exponential damage evolution function. The fracture energies and the threshold stresses are set as damage material parameters for the longitudinal muscular, the circumferential muscular and the submucosal collagenous layers. A biaxial tensile simulation of a linear brick element has been performed to validate the applicability of the estimated material parameters. The model successfully simulates the biomechanical response of the large intestine under physiological and non-physiological loads.
KW  - biaxial tensile experiment
KW  - anisotropy
KW  - hyperelastic
KW  - constitutive modeling
KW  - damage
Y1  - 2022
U6  - http://dx.doi.org/10.3390/bioengineering9100528
SN  - 2306-5354
N1  - Der Artikel gehört zum Sonderheft "Computational Biomechanics"
VL  - 9
IS  - 10, Early Access
SP  - 1
EP  - 17
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Meyer, Carolin
A1  - Gaalen, Kerstin van
A1  - Leschinger, Tim
A1  - Scheyerer, Max J.
A1  - Neiss, Wolfram F.
A1  - Staat, Manfred
A1  - Müller, Lars P.
A1  - Wegmann, Kilian
T1  - Kyphoplasty of Osteoporotic Fractured Vertebrae: A Finite Element Analysis about Two Types of Cement
JF  - BioMed Research International
Y1  - 2019
U6  - http://dx.doi.org/10.1155/2019/9232813
SP  - Article ID 9232813
ER  - 
TY  - JOUR
A1  - Leschinger, Tim
A1  - Besch, Katharina
A1  - Aydin, Cansu
A1  - Staat, Manfred
A1  - Scaal, Martin
A1  - Müller, Lars Peter
A1  - Wegmann, Kilian
T1  - Irreparable rotator cuff tears: a biomechanical comparison of superior capsuloligamentous complex reconstruction techniques and an interposition graft technique
JF  - The Orthopaedic Journal of Sports Medicine
Y1  - 2019
U6  - http://dx.doi.org/10.1177/2325967119864590
VL  - 7
IS  - 8
SP  - 1
EP  - 5
ER  - 
TY  - JOUR
A1  - Anding, Ralf
A1  - Tabaza, Ruth
A1  - Staat, Manfred
A1  - Trenz, Eva
A1  - Lohmann, Philipp
A1  - Klinge, Uwe
A1  - Kirschner-Hermanns, Ruth
T1  - Introducing a method of in vitro testing of different anchoring systems used for female incontinence and prolapse surgery
JF  - BioMed research international
Y1  - 2013
SN  - 1110-7251 (E-Journal); 2314-6141 (E-Journal); 1110-7243 (Print); 2314-6133 (Print)
VL  - Vol. 2013
SP  - Article ID 401417
ER  - 
TY  - JOUR
A1  - Hackl, Michael
A1  - Nacov, Julia
A1  - Kammerlohr, Sandra
A1  - Staat, Manfred
A1  - Buess, Eduard
A1  - Leschinger, Tim
A1  - Müller, Lars P.
A1  - Wegmann, Kilian
T1  - Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure
JF  - The American Journal of Sports Medicine
Y1  - 2021
U6  - http://dx.doi.org/10.1177/03635465211006138
SN  - 1552-3365
SN  - 0363-5465
VL  - 49
IS  - 7
SP  - 1847
EP  - 1853
PB  - Sage
CY  - London
ER  - 
TY  - JOUR
A1  - Duong, Minh Tuan
A1  - Nguyen, Nhu Huynh
A1  - Tran, Thanh Ngoc
A1  - Tolba, R. H.
A1  - Staat, Manfred
T1  - Influence of refrigerated storage on tensile mechanical properties of porcine liver and spleen
JF  - International biomechanics
Y1  - 2015
U6  - http://dx.doi.org/10.1080/23335432.2015.1049295
SN  - 2333-5432
VL  - Vol. 2
IS  - Iss. 1
SP  - 79
EP  - 88
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Nguyen, Nhu Huynh
A1  - Duong, Minh Tuan
A1  - Tran, Thanh Ngoc
A1  - Pham, Phu Tinh
A1  - Grottke, O.
A1  - Tolba, R.
A1  - Staat, Manfred
T1  - Influence of a freeze–thaw cycle on the stress–stretch curves of tissues of porcine abdominal organs
JF  - Journal of Biomechanics
N2  - The paper investigates both fresh porcine spleen and liver and the possible decomposition of these organs under a freeze–thaw cycle. The effect of tissue preservation condition is an important factor which should be taken into account for protracted biomechanical tests. In this work, tension tests were conducted for a large number of tissue specimens from twenty pigs divided into two groups of 10. Concretely, the first group was tested in fresh state; the other one was tested after a freeze-thaw cycle which simulates the conservation conditions before biomechanical experiments. A modified Fung model for isotropic behavior was adopted for the curve fitting of each kind of tissues. Experimental results show strong effects of the realistic freeze–thaw cycle on the capsule of elastin-rich spleen but negligible effects on the liver which virtually contains no elastin. This different behavior could be explained by the autolysis of elastin by elastolytic enzymes during the warmer period after thawing. Realistic biomechanical properties of elastin-rich organs can only be expected if really fresh tissue is tested. The observations are supported by tests of intestines.
KW  - Autolysis
KW  - Decomposition
KW  - Freeze–thaw process
KW  - Spleen
KW  - Liver
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jbiomech.2012.07.008
SN  - 1873-2380
VL  - 45
IS  - 14
SP  - 2382
EP  - 2386
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Doorschodt, B. M.
A1  - Schreinemachers, M. C. J. M.
A1  - Behbahani, Mehdi
A1  - Florquin, S.
A1  - Weis, J.
A1  - Staat, Manfred
A1  - Tolba, R. H.
T1  - Hypothermic machine perfusion of kidney grafts: which pressure is preferred
JF  - Annals of Biomedical Engineering. 39 (2011), H. 3
Y1  - 2011
SN  - 1573-9686
SP  - 1051
EP  - 1059
PB  - Springer
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Laack, Walter van
A1  - Levers, A.
A1  - Staat, Manfred
T1  - Gonarthrosetherapie auf Kernspinresonanzbasis mit MBST-Vierjahresbeobachtungen
JF  - Orthopädische Nachrichten : Zeitung für Orthopädie und Unfallchirurgie. 2013, H. 7/8
Y1  - 2013
SN  - 1437-2193
SP  - 13
PB  - Biermann
CY  - Köln
ER  - 
TY  - JOUR
A1  - Jung, Alexander
A1  - Staat, Manfred
A1  - Müller, Wolfram
T1  - Flight style optimization in ski jumping on normal, large, and ski flying hills
JF  - Journal of biomechanics
Y1  - 2013
SN  - 1873-2380 (E-Journal); 0021-9290 (Print)
N1  - Corrigendum to “Flight style optimization in ski jumping on normal, large, and ski flying hills” [J. Biomech 47 (2014) 716-722] Journal of Biomechanics, 2018;71:313.
VL  - Vol. 47
IS  - Iss. 3
SP  - 716
EP  - 722
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Novacek, V.
A1  - Tran, Thanh Ngoc
A1  - Klinge, U.
A1  - Tolba, R. H.
A1  - Staat, Manfred
A1  - Bronson, D. G.
A1  - Miesse, A. M.
A1  - Whiffen, J.
A1  - Turquier, F.
T1  - Finite element modelling of stapled colorectal end-to-end anastomosis : Advantages of variable height stapler design
JF  - Journal of Biomechanics
N2  - The impact of surgical staplers on tissues has been studied mostly in an empirical manner. In this paper, finite element method was used to clarify the mechanics of tissue stapling and associated phenomena. Various stapling modalities and several designs of circular staplers were investigated to evaluate the impact of the device on tissues and mechanical performance of the end-to-end colorectal anastomosis. Numerical simulations demonstrated that a single row of staples is not adequate to resist leakage due to non-linear buckling and opening of the tissue layers between two adjacent staples. Compared to the single staple row configuration, significant increase in stress experienced by the tissue at the inner staple rows was observed in two and three rows designs. On the other hand, adding second and/or third staple row had no effect on strain in the tissue inside the staples. Variable height design with higher staples in outer rows significantly reduced the stresses and strains in outer rows when compared to the same configuration with flat cartridge.
KW  - Variable height stapler design
KW  - Anastomotic leakage
KW  - Finite element modelling
KW  - End-to-end colorectal anastomosis
KW  - Surgical staplers
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jbiomech.2012.07.021
SN  - 1873-2380
VL  - 45
IS  - 115
SP  - 2693
EP  - 2697
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Heitzer, M.
T1  - FEM-computation of load carrying capacity of highly loaded passive components by direct methods. Heitzer, M. ; Staat, M.
JF  - Nuclear Engineering and Design. 193 (1999), H. 3
Y1  - 1999
SN  - 0029-5493
SP  - 349
EP  - 358
ER  - 
TY  - JOUR
A1  - Pham, Phu Tinh
A1  - Staat, Manfred
T1  - FEM-based shakedown analysis of hardening structures
JF  - Asia Pacific journal on computational engineering
N2  - This paper develops a new finite element method (FEM)-based upper bound algorithm for limit and shakedown analysis of hardening structures by a direct plasticity method. The hardening model is a simple two-surface model of plasticity with a fixed bounding surface. The initial yield surface can translate inside the bounding surface, and it is bounded by one of the two equivalent conditions: (1) it always stays inside the bounding surface or (2) its centre cannot move outside the back-stress surface. The algorithm gives an effective tool to analyze the problems with a very high number of degree of freedom. Our numerical results are very close to the analytical solutions and numerical solutions in literature.
Y1  - 2014
U6  - http://dx.doi.org/10.1186/2196-1166-1-4
SN  - 2196-1166 (E-Journal)
IS  - 1
SP  - Article No. 4
PB  - SpringerOpen
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Tran, Ngoc Trinh
A1  - Trinh, Tu Luc
A1  - Dao, Ngoc Tien
A1  - Giap, Van Tan
A1  - Truong, Manh Khuyen
A1  - Dinh, Thuy Ha
A1  - Staat, Manfred
T1  - FEM shakedown analysis of structures under random strength with chance constrained programming
JF  - Vietnam Journal of Mechanics
N2  - Direct methods, comprising limit and shakedown analysis, are a branch of computational mechanics. They play a significant role in mechanical and civil engineering design. The concept of direct methods aims to determine the ultimate load carrying capacity of structures beyond the elastic range. In practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and constraints. If strength and loading are random quantities, the shakedown analysis can be formulated as stochastic programming problem. In this paper, a method called chance constrained programming is presented, which is an effective method of stochastic programming to solve shakedown analysis problems under random conditions of strength. In this study, the loading is deterministic, and the strength is a normally or lognormally distributed variable.
KW  - limit analysis
KW  - shakedown analysis
KW  - chance constrained programming
KW  - stochastic programming
KW  - reliability of structures
Y1  - 2022
U6  - http://dx.doi.org/10.15625/0866-7136/17943
SN  - 0866-7136
SN  - 2815-5882
VL  - 44
IS  - 4
SP  - 459
EP  - 473
PB  - Vietnam Academy of Science and Technology (VAST)
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Failure probabilities of the primary circuit pressure boundary of an HTR-Module for process heat generation under accident conditions for different failure modes
JF  - Nuclear Engineering and Design. 144 (1993), H. 1
Y1  - 1993
SN  - 0029-5493
SP  - 53
EP  - 67
ER  - 
TY  - JOUR
A1  - Gorissen, P.
A1  - Staat, Manfred
A1  - Laack, Walter van
T1  - Experimentelle Kraftmessungen als Beitrag zur Wirksamkeitsbeurteilung von Schienbeinschonern im Fußballsport
T1  - Experimental measurement of forces as a contribution to evaluate the effectiveness of shin guards in soccer
JF  - OUP Zeitschrift für die orthopädische und unfallchirurgische Praxis
N2  - Diese Studie beschäftigte sich mit der Dämpfungswirkung von Schienbeinschonern, wie sie beim Fußball zum Einsatz kommen. Sie wurde mit Hilfe eines Pendelhammers durchgeführt, der verschiedene Aufschlagkräfte auf die Schoner ermöglichte. Dabei wurde deutlich, dass Schienbeinschoner die beste Wirkung bei Maximalkräften unterhalb von 5kN erreichen können, dass bei größerer Belastung allerdings Verbesserungsbedarf besteht. Hierfür konnte, u.a. durch den Einsatz neuer Materialien, ein guter Ansatzpunkt im „adäquaten Zusammenspiel von Schale und Polsterung“ der Schoner gefunden werden. Die Untersuchung hat weiterhin gezeigt, dass zumindest teilweise eine deutliche Verbesserung der Dämpfungswirkung der Schienbeinschoner in den letzten Jahren erreicht werden konnte.
N2  - This study was conducted to test the damping effects of commercially available soccer shin guards on their damping effects. Therefore a pendulum impact apparatus with varying impact forces was used. It became clear that shin guards show the best effect at maximum forces of less than 5kN. There is however a need for improvement at greater impact forces. A good starting point was found in an „appropriate interaction of shell and padding” of the shin guard. It was further clarified that a significant improvement on the damping effect could be achieved at least partially over the last years.
KW  - Fußball
KW  - Schienbeinschoner
KW  - Aufschlagversuch
Y1  - 2012
U6  - http://dx.doi.org/10.3238/oup.2012.0010-0015
SN  - 2193-5785
VL  - 1
IS  - 1
SP  - 10
EP  - 15
PB  - Deutscher Ärzte-Verlag
CY  - Köln
ER  - 
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  -