ON THE DETERMINATION OF THE NON-LINEAR LONGITUDINAL MECHANICAL BEHAVIOUR OF SHORT-FIBRE COMPOSITES BY A THREE-DIMENSIONAL FINITE ELEMENT PROCEDURE

Author(s):  
J.I. CURISKIS
Author(s):  
Xianbin Du ◽  
Youqun Zhao ◽  
Qiang Wang ◽  
Hongxun Fu

An innovative non-pneumatic tyre called the mechanical elastic wheel is introduced; significant challenges exist in the prediction of the dynamic interaction between this mechanical elastic wheel and soil containing an obstacle owing to its highly non-linear properties. To explore the mechanical properties of the mechanical elastic wheel and the soil, the finite element method is used, and a non-linear three-dimensional finite element wheel–soil interaction model is also established. Hyperelastic incompressible rubber, which is one of the main materials of the mechanical elastic wheel, is analysed using the Mooney–Rivlin model. The modified Drucker–Prager cap plasticity constitutive law is utilized to describe the behaviour of the soil, and the obstacle is represented as an elastic body. Simulations with different rotational speeds of the mechanical elastic wheel were conducted. The stress distribution and the displacement of the mechanical elastic wheel and the soil were obtained, and the effects of different rotational speeds on the displacement, the velocity and the acceleration of the hub centre are presented and discussed in detail. These results can provide useful information for optimization of the mechanical elastic wheel.


Author(s):  
Chonlada Luangarpa ◽  
Hideo Koguchi

In the present study, a conservative integral based on the Betti reciprocal principle is formulated in order to obtain the intensity of singularity at a vertex of the interface in three-dimensional piezoelectric bi-material bonded joints. To our knowledge, there are few studies on the determination of the intensity of singularity in the three-dimensional piezoelectric bonded joints. In addition, no study on the determination of the intensity of singularity in the 3D piezoelectric bonded joints using the conservative integral has been conducted. Eigenanalysis formulated using a three-dimensional finite element method (FEM) is used to calculate the order of stress singularity, angular variables of mechanical displacements, stresses, electric displacements and electric potential. In order to investigate the influence of an integral area on the accuracy of the results, models with various integral areas are used. The results are compared with those obtained from FEM.


2012 ◽  
Vol 91 (12) ◽  
pp. 1184-1189 ◽  
Author(s):  
P. Streckbein ◽  
R.G. Streckbein ◽  
J.F. Wilbrand ◽  
C.Y. Malik ◽  
H. Schaaf ◽  
...  

Micro-gaps and osseous overload in the implant-abutment connection are the most common causes of peri-implant bone resorption and implant failure. These undesirable events can be visualized on standardized three-dimensional finite element models and by radiographic methods. The present study investigated the influence of 7 available implant systems (Ankylos, Astra, Bego, Brånemark, Camlog, Straumann, and Xive) with different implant-abutment connections on bone overload and the appearance of micro-gaps in vitro. The individual geometries of the implants were transferred to three-dimensional finite element models. In a non-linear analysis considering the pre-loading of the occlusion screw, friction between the implant and abutment, the influence of the cone angle on bone strain, and the appearance of micro-gaps were determined. Increased bone strains were correlated with small (< 15°) cone angles. Conical implant-abutment connections efficiently avoided micro-gaps but had a negative effect on peri-implant bone strain. Bone strain was reduced in implants with greater wall thickness (Ankylos) or a smaller cone angle (Bego). The results of our in silico study provide a solid basis for the reduction of peri-implant bone strain and micro-gaps in the implant-abutment connection to improve long-term stability.


2012 ◽  
Vol 56 (1) ◽  
pp. 81-87
Author(s):  
Liviu Bereteu ◽  
Dorin Simoiu

AbstractIn this paper it is present the influence of the wind on a parabolic antenna, in order to study this influence it was made simulations of air flow over a parabolic antenna. The simulations are made with antenna positioned at 90°, 135°. A three – dimensional finite element is simulated for determination of the antenna displacement.


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