TY  - CHAP
A1  - Nix, Yvonne
A1  - Frotscher, Ralf
A1  - Staat, Manfred
ED  - Eberhardsteiner, J.
T1  - Implementation of the edge-based smoothed extended finite element method
T2  - Proceedings 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012
Y1  - 2012
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  - 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  - 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  - 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  - 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  - 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  - 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  - BOOK
A1  - Staat, Manfred
A1  - Heitzer, M.
A1  - Yan, Ai-Min
A1  - Khoi, Vu Duc
A1  - Nguyen, Dang Hung
A1  - Valdoire, F.
A1  - Lahousse, A.
T1  - Limit Analysis of Defects
Y1  - 2000
SN  - 0944-2952
N1  - Bericht des Forschungszentrums, Jül-3746, Jülich (2000)
PB  - Forschungszentrum Jülich
CY  - Jülich
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  - 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  - CHAP
A1  - Staat, Manfred
A1  - Heitzer, Michael
T1  - Limit and shakedown analysis for plastic design
N2  - Limit and shakedown theorems are exact theories of classical plasticity for the direct computation of safety factors or of the load carrying capacity under constant and varying loads. Simple versions of limit and shakedown analysis are the basis of all design codes for pressure vessels and pipings. Using Finite Element Methods more realistic modeling can be used for a more rational design. The methods can be extended to yield optimum plastic design. In this paper we present a first implementation in FE of limit and shakedown analyses for perfectly plastic material. Limit and shakedown analyses are done of a pipe–junction and a interaction diagram is calculated. The results are in good correspondence with the analytic solution we give in the appendix.
KW  - Einspielen <Werkstoff>
KW  - Traglast
KW  - Finite-Elemente-Methode
KW  - Traglastanalyse
KW  - Einspielanalyse
KW  - FEM
KW  - limit analysis
KW  - shakedown analysis
Y1  - 1997
ER  - 
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  - CHAP
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  - Limit and shakedown analysis of structures under random strength
T2  - Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022
N2  - Direct methods comprising limit and shakedown analysis is a branch of computational mechanics. It plays a significant role in mechanical and civil engineering design. The concept of direct method aims to determinate the ultimate load bearing capacity of structures beyond the elastic range. For practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and onstraints. If strength and loading are random quantities, the problem of shakedown analysis is considered as stochastic programming. This paper presents a method so called chance constrained programming, an effective method of stochastic programming, to solve shakedown analysis problem under random condition of strength. In this our investigation, the loading is deterministic, the strength is distributed as normal or lognormal variables.
KW  - Reliability of structures
KW  - Stochastic programming
KW  - Chance constrained programming
KW  - Shakedown analysis
KW  - Limit analysis
Y1  - 2022
SN  - 978-604-357-084-7
SP  - 510
EP  - 518
PB  - Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik)
CY  - Hanoi
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Limit and shakedown analysis under uncertainty
JF  - International journal of computational methods : IJCM
Y1  - 2013
SN  - 0219-8762
SP  - Publ. online
PB  - World Scientific Publishing
CY  - Singapore
ER  - 
TY  - JOUR
A1  - Staat, Manfred
T1  - Limit and shakedown analysis under uncertainty
JF  - Tap chi Khoa hoc & ung dung - Dai hoc Ton Duc Thang
Y1  - 2012
N1  - = Journal of Applied Sciences - Ton Duc Thang University
VL  - 19
SP  - 45
EP  - 47
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Heitzer, M.
T1  - Limit and Shakedown Analysis Using a General Purpose Finite Element Code
JF  - Proceedings of NAFEMS World Congress '97 on Design, Simulation & Optimisation : reliability & applicability of computational methods ; Stuttgart, Germany, 9 - 11 April 1997
Y1  - 1997
SN  - 1-87437-620-4
SP  - 522
EP  - 533
PB  - NAFEMS
CY  - Glasgow
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Heitzer, M.
T1  - Limit and Shakedown Analysis with Uncertain Data
JF  - Stochastic optimization techniques : numerical methods and technical applications / Marti, K. [ed]
Y1  - 2002
SN  - 3-540-42889-5
SP  - 241
EP  - 254
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - CHAP
A1  - Staat, Manfred
A1  - Tran, Thanh Ngoc
A1  - Pham, Phu Tinh
T1  - Limit and shakedown reliability analysis by nonlinear programming
N2  - 7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs.
KW  - Finite-Elemente-Methode
KW  - Limit analysis
KW  - Shakedown analysis
Y1  - 2008
ER  - 
TY  - JOUR
A1  - Staat, Manfred
A1  - Vu, Khoi Duc
T1  - Limit loads of circumferentially flawed pipes and cylindrical vessels under internal pressure
JF  - International Journal of Pressure Vessels and Piping. 83 (2006), H. 3
Y1  - 2006
SN  - 0308-0161
SP  - 188
EP  - 196
ER  -