TY  - JOUR
A1  - Hasan, Istabrak
A1  - Keil, Ludger
A1  - Staat, Manfred
A1  - Wahl, Gerhard
A1  - Bourauel, Christoph
T1  - Determination of the frictional coefficient of the implant-antler interface : experimental approach
JF  - Biomedical Engineering / Biomedizinische Technik
N2  - The similar bone structure of reindeer antler to human bone permits studying the osseointegration of dental implants in the jawbone. As the friction is one of the major factors that have a significant influence on the initial stability of immediately loaded dental implants, it is essential to define the frictional coefficient of the implant-antler interface. In this study, the kinetic frictional forces at the implant-antler interface were measured experimentally using an optomechanical setup and a stepping motor controller under different axial loads and sliding velocities. The corresponding mean values of the static and kinetic frictional coefficients were within the range of 0.5–0.7 and 0.3–0.5, respectively. An increase in the frictional forces with increasing applied axial loads was registered. The measurements showed an evidence of a decrease in the magnitude of the frictional coefficient with increasing sliding velocity. The results of this study provide a considerable assessment to clarify the suitable frictional coefficient to be used in the finite element contact analysis of antler specimens.
Y1  - 2012
SN  - 1862-278X
VL  - 57
IS  - 5
SP  - 359
EP  - 363
PB  - De Gruyter
CY  - Berlin
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  - 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  - https://doi.org/10.1016/j.engfracmech.2012.05.017
SN  - 0013-7944
VL  - 97
SP  - 314
EP  - 333
PB  - Elsevier
CY  - Amsterdam
ER  -