Abstract
This paper presents three-dimensional finite element method analyses of the distribution of equivalents stress of Von Mises. Induced around a cavity located in the bone cement
polymethylmethacrylate (PMMA). The presences and effect of its position in the cement was demonstrated,thus on the stress level and distribution. The porosity interaction depending on their positions, and their orientations on the interdistances their mechanical behaviour of bone cement effects were analysed. The obtained results show that micro-porosity located in the proximal and distal zone of the prosthesis is subject
to higher stress field. We show that the breaking strain of the cement is largely taken when the cement, containing the porosities very close adjacent to each other.
Key Words
bone cement; porosity; fracture mechanics; stress concentration; finite element method
Address
Mechanics and Physics of Materials Laboratory, Djillali Liabes University of Sidi Bel-Abbes,BP89 cité Larbi Ben M\'hidi, Sidi Bel-Abbes, Algeria
Abstract
In this paper a method for simultaneous swift non-linear analysis and optimal design/posture of mechanical/biomechanical systems is presented. The method is developed to get advantages of iterations in non-linear analysis and/or generations in genetic algorithm (GA) for the purpose of efficient analysis within the optimal design/posture. The method is applicable for both size and geometry optimizations wherein material and geometry non-linearity are present. In addition to established mechanical systems, the method can solve biomechanical models of human musculoskeletal system. Optimization-based procedures are popular methods for resolving the redundancy at joints wherein the number of unknown muscle forces is far more than the number of equilibrium equations. These procedures involve optimization of a cost function(s) which is assumed to be consistent with the central nervous system
Key Words
optimal design; biomechanical systems; non-linear analysis; genetic algorithm
Address
I. Shojaei, B. Bazrgari: Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
A. Kave: Centre of Excellence for Fundamental Studies in Civil Engineering, Iran University of Science and Technology, Tehran, Iran
H. Rahami: School of Engineering Science, College of Engineering, University of Tehran, Tehran, Iran
Abstract
Treatments for asthma are largely pharmaceutical, with some therapies also utilising alternative breathing techniques. The objective of both medical and alternative methods is to relax contracted airway smooth muscle (ASM). In normal subjects, tidal breathing- and deep inspiration-oscillations are believed to have a bronchodilatory effect. Similarly, application of length oscillations to isolated, contracted ASM also elicits muscle relaxation. As a means of investigating more-effective alternative treatment methods for contracted airways, we analyse the combined effects of bronchodilators and length oscillations on isolated, contracted ASM. The contractile state of the muscle tissue prior to treatment is of primary interest. Thereafter, the effect of applying a combination of small superimposed length oscillations with tidal breathing-like oscillations to ASM is studied alone and in combination with a common bronchodilator, isoproterenol (ISO). This work suggests that relaxation of isolated, contracted ASM following application of combined oscillations and ISO is larger than treatments of either combined oscillations or ISO alone. Further, the observed oscillation-associated relaxation is found to be amplitude- rather than frequency- dependent. This study gives additional insight into the role of oscillations and bronchodilators on contracted airways.
Key Words
isoproterenol; length oscillations; airway smooth muscle; porcine
Address
Institute of Biomedical Technologies, Auckland University of Technology, Auckland, New Zealand
Abstract
\"Dynamic stabilization\" systems have been developed in recent years to treat degenerative disorders of the spinal column. In contrast to arthrodesis (fusion), the aim here is to conserve intervertebral mobility to maximize comfort. When developing innovative concepts, many mechanical tests need to be carried out in order to validate the different technological solutions. The present study focuses on the B Dyn
Abstract
A problem faced by oil companies is the maintenance of the location register of pipelines that cross the surf zone, the regular survey of their location, and also their inspection. A survey of the state of art did not allow identifying operating systems capable of executing such tasks. Commercial technologies available on the market also do not address this problem and/or do not satisfy the presented requirements. A possible solution is to use robotic systems which have the ability to walk on the shore and in the surf zone, subject to existing currents and ripples, and being able to withstand these ambient conditions. In this sense, the authors propose the development of a spider crab biologically inspired robot to achieve those tasks. Based on these ideas, this work presents a biomechanical study of the spider crab, its modeling and simulation using the SimMechanics toolbox of Matlab/Simulink, which is the first phase of this more vast project. Results show a robot model that is moving in an \"animal like\" manner, the locomotion, the algorithm presented in this paper allows the crab to walk sideways, in the desired direction.
Key Words
biomechanics; bioinspired robotics Spider Crab; modeling; simulation; SimMechanics
Address
Rita Rynkevic and M. Arcelina Marques: Physics Department, School of Engineering – Polytechnic of Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal
Manuel F. Silva: INESC TEC - INESC Technology and Science (formerly INESC Porto) and ISEP/IPP - School of Engineering, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida,
4200-072 Porto, Portugal
