Applied Mechanics and Materials Vol. 245

Abstract: Rehabilitation of joints that underwent major surgery, involves reducing postoperative pain and inflammation. Many pharmaceutical product used in reducing joint pain are based on the extended-release technology and becoming increasingly important in research domain. The performance of extended-release matrix tablets is dependent on the solid dosage properties like matrix materials used, which are semi-synthetic polymer like hydroxypropyl methylcellulose (HPMC) and sodium carboxy methylcellulose (Na CMC). Depending on the properties of the polymer used, drug release from the tablets may be controlled by erosion mechanism and surface roughness. In a physiological environment, the release of drug from a solid dosage form requires a gradual erosion of solid shape with simultaneous change of surface roughness. This paper presents the influence of surface erosion of solid dosage forms on the surface roughness and the release of the analgesic and anti-inflammatory substances in a biological environment similar to the human digestive juice.

Abstract: . This work is focused on stress - strain analysis of a mandible fracture behavior in the case of straight and oblique fracture. For this problem the computational modelling was chosen with using finite element method. Mandible was created based on the 3D scanning and CT images. Using these procedures a STL model of mandible with cortical and cancellous bone tissue was created. A volume model of lower jaw with applied reconstruction plate was created in CAD software. Fracture in the chin region was modelled directly in the program ANSYS. The cancellous bone tissue is modeled with different mechanical properties, which corresponds to the varying quality of this tissue. An assessment of differences in the behavior of straight and oblique fracture is presented in this work.

Abstract: The presented work deals with the creation of computational model of total hip arthroplasty and the subsequent performance of stress-strain analysis. The models of geometry of the pelvis and the femur were created on base of CT data. In To this model were fitted both of components, i.e. femoral stem and acetabular liner. On this system was subsequently modeled the real load conditions. Just real loading of the endoprosthesis leads to wear and it has great influence on the deterioration of bone tissue. These properties were simulated under the acetabular component. The behavior of the whole system is assessed on base of stress-strain analysis. From comparison the obtained results with clinical study it is evident that the places, that are dangerous in terms of establishment wear particles, are identical. This whole issue is very topical today.

Abstract: Studies and researches in medical devices made evident the need of new systems and technologies for locomotors recovery of human body as to reduce the reintegration time in normal activities and, not the least, to improve the recovery quality, to give the possibility to perform natural movements identical to those before the suffered injury. Thus, the purpose of this paper is to obtain the 3D virtual model of a mechanism describing the hand kinematics, and a real medical prototype device to be used in locomotors recovery of the hand. In order to perform the movements, pneumatic fluidic actuators are used, considering that they are flexible, small, made especially for this project. A specialized software for assisted design is used to obtain the virtual model and for the fabrication of device component parts Rapid-Prototyping technology is applied, the Fused Deposition Modeling principle (FDM).

Abstract: This paper describes an approach of automation selecting the proper male sperm cells to be used for female egg cell injection. Connected components analyze is used for image processing and micro object tracking.

Abstract: This paper presents the analysis of electro-mechanical design, selection of materials and manufacturing techniques for physical construction, dynamics, control etc. of a novel variable impedance compact compliant series elastic actuator (SEA) for human-friendly robotics applications. The electro-mechanical design consists of a servomotor, a ball screw, a torsional spring connecting the servomotor and the ball screw via a pair of spur gear, and a set of translational springs connecting the ball screw nut to the output link. The translational springs have low stiffness and these are used to handle low force operations that reduce non-linear friction, output impedance, impact etc. The torsional spring is in the high speed range, has high effective stiffness and it enhances the system bandwidth for large force operations when the translational springs are fully compressed. Suitable materials and appropriate manufacturing techniques for the construction of the actuator are discussed. Kinematics and working principle of the actuator are analyzed. The actuator model is simulated on the physical implementation for dynamics and control for different conditions. Simulation results prove satisfactory performances of the design. Then, advantages of the design over its existing counterparts are discussed, and its potential applications and future extensions are mentioned.

Abstract: The paper presents an experimental model of PWM controlled proportional pneumatic direction control valve developed by the authors, as well as the functioning of a pneumatic system that incorporates the original solution of valve. The main parameters that control the system can be settled using a software application developed for that purpose.

Abstract: This paper presents results concerning the vegetable oils as an renewable energy source, with applications for production of electricity or heat. The experiments followed the ignition and the stability of the combustion process of the liquid biofuels and the evaluation of pollutants emissions. The combustion process of liquid fuels additivated with vegetable oils proves their advantage from the point of view of energy efficiency and of the environment protection, the emissions values falling in the allowed interval.

Abstract: Using higher-order terms of the Williams expansion is necessary for assessment of fracture behavior of quasi-brittle materials. Multi-parameter fracture mechanics enables more accurate determination of the stress/displacement field even in a larger distance from the crack tip, thus the extended zone with non-elastic behavior typical for this kind of material can be well described. The so-called over-deterministic method (ODM) seems to be a suitable tool for the higher-order terms coefficients calculation, but its utilization exhibits some limitations. Therefore, extensive analyses have been performed in order to summarize recommendations regarding the mesh sensitivity, boundary conditions influence, etc. List of pieces of advice and author’s experiences presented in the end of this work should contribute to more accurate and effective utilization of the ODM.

Abstract: The primary objective of research is to determine the improved structural efficiency of plates can be with variable fiber spacing. The Post-buckling of laminated composite plate with variable fiber spacing is obtained numerically, using eight node isoparametric quadrilateral elements (serendipity element) with five degree of freedom per node. The mathematical formulation is based on first-order shear deformation theory and von-Karman non-linearity. The effect of the initial geometric imperfection, fiber spacing, orientation fiber, and direction of in-plane loading were considered. Numerical results for boron/Epoxy fiber reinforced laminates are presented for the different effects of the composite plate under in-plane loading. This study showed that the post buckling behavior of composite plate very sensitive for type of distribution fiber and the seventh distribution equation gives maximum buckling load and smallest deformation.