Applied Mechanics and Materials Vol. 896

Abstract: The hip joint is spheroidal type which allows three movement axes, with a special importance in statics and locomotion. The study of the hip joint by computerized tomography of a male, 52-year-old male patient at the Craiova County Emergency Clinical Hospital was started using Siemens equipment comprised of a magnetic resonance device and a computed tomography apparatus. Were analyzed: hip joint with the two main components of the femur and pelvic bones. To obtain the virtual components of the hip joint, 143 tomographic images from different planes were analyzed. CT images were used to define the normal hip joint. Also, the arthrotic hip virtual model was generated. These two virtual models were subjected to normal walking load and were simulated by the finite element method. The results were analyzed and compared, and important conclusions were finally drawn.

Abstract: Dental wear has accompanied human evolution, being strictly related to its way of life. Dental wear is a lesion of dental hard tissue commonly found in dental practice. Starting from the virtual skull model, the virtual models of the two upper premolars on the left hemisphere were generated, then the finite element method evaluated the stresses, displacements and strains generated by the resistance forces from the dental tissues of the two premolars during mandibular movements with occlusal contact. It is found that the value of these results increases as dental wear increases. This phenomenon is more visible in the teeth where the value almost doubles. Two explanations could be given for this situation: mechanically, these stresses are inversely proportional to the volume of the dental structures and, as they reduce, through dental wear, increase the stress, also, the sharp edges resulting from dental wear are mechanical stress concentrators.

Abstract: This paper addresses to a research of a dynamic answer obtained through numerical simulations of a human ankle joint implant with finite element method. The research background consists of an inverse dynamic analysis based on Newton-Euler formalism completed with Lagrange’s multipliers method. Thus, a parameterized virtual model of a human ankle joint was elaborated and simulated together with the implant, in dynamic conditions similar with real ones in reality. A results numerical processing was obtained with the aid of MSC Nastran and important results were obtained for orthopedic implants design.

Abstract: This research is pointed to the experimental development of the laws of motion generated by the trajectories of the joints of the lower limb of the human locomotion system, for the activity of stepping. Ankle rehabilitation is a very complicated problem considering both the complexity of the biomechanical system and the pathologies that generate its incapacity. In order to determine the laws of motion necessary to perform the experimental analysis, an advanced image acquisition and analysis equipment was used, named CONTEMPLAS. By analyzing the human biomechanical system with this equipment, it was possible to determine the trajectories of the points attached to it, both in a single plane and in space using one or two ultra-fast video cameras. The experimental data gathered in this research allows us to create a database in order to design future special orthotic devices for people locomotion rehabilitation.

Abstract: In the present paper, a review of some of the common orthoses designed for osteoarthritis of the knee is performed. The functional and constructive characteristics and the main advantages that recommend them for use are presented.

Abstract: To combat climate change, there is growing support for the use of clean and sustainable energy, which will result in the reduction of greenhouse gas emissions. In recent years, in response to an increasing need for wind turbines in the field of energy, intended for the production of electricity, their size has increased. The effect of increasing the size of the machines, and in particular the size of the blades, led to the appearance of vibrational phenomena and the instability of aeroelastic origin (vibrations, noises). Basically, this work highlights the dynamic effects on a blade during its rotation taking into account, on the one hand, the mechanical forces (the centrifugal effect, the inertial effect) and, on the other hand, the aerodynamic effects. The blade, which is in motion, is subjected to three types of deformations: longitudinal, transverse and twisting. We were interested in the twisting and transverse vibrations, the equations we obtained with Hamilton's variational principle.

Abstract: In this paper, we will compare the methods of solving with explicit or implicit finite difference of the partial differential equations that define the mechanical models of hydrodynamics movements, thermodynamics or those that define the vibration movements with the ones that use integral transforms. By applying the Laplace and Fourier transforms, finite in sine or cosine, depending on the boundary conditions of the real physical problem, it leads to the algebraic approach of the problem, which reduces the difficulty of solving partial differential equations. The errors obtained for the solution of partial differential equations using different methods are within the standard norms. However, in terms of calculus precision, the use of integral transforms is more advantageous.

Abstract: The dynamics of a slider-crank mechanism is developed using Kane's equations of motion. The motor torque is a function of the derivative of the generalized coordinate. The nonlinear equations of motion are solved using MATLAB numerical techniques. The sample entropy is calculated for different angular velocities of the crank.

Abstract: This paper addresses to a dynamic modal analysis of a crank-type mechanism. The proposed mechanism will have all the components considered as deformable bodies. Thus, the proposed research consists on two methods, namely an analytical and a numerical one. The analytical method allows to identify the static and dynamic components of the matrices that from the equation of motion based on the Kane formalism and the finite element modeling. The numerical method is based on the virtual prototyping of the whole assembly with the ADAMS software. In this case, for the deformable bodies analysis, will be used the method of superposition which have on its base the modal analysis and the RR Craig and MCC Bampton procedure.