In the first stage of research, real bone components were analyzed to determine the main visual geometric shapes. After that, it was used a CT or MRI device to get parallel sections of studied bone components. In the third stage, the images were transferred to a 2D CAD software like AutoCAD, where the outer and inner contours of the bone were approximated by polygonal lines composed of multiple segments. To obtain virtual bones was used a parametric CAD software that allows defining models with a high degree of difficulty. The contours were transferred to a 3D CAD software, which, step by step, each section was used to define each virtual component of bone. For some components, such as vertebrae, bones of the jaw, the skull bones, was used in a preliminary model consists of curves in parallel planes. Based on this model can be defined the main curves for the final virtual 3D solid model. Also, were defined innovative orthopedic metal components as tibia nail, plates and screws or prosthetic elements. Were defined simulations to determine the behavior of the new orthopedic models through FEA method.
The paper presents some methods used to analyze human bone joints. First, there were defined the "hard" parts as the main bone components and "soft" parts as ligaments or menisci using CT images. These components are imported into a parameterized environment assembly module and a biomechanical model of human walking is being obtained, which is exported to a kinematic simulation environment and finite element analysis, where first the kinematic parameters are defined. With these defined parameters, the kinematic and dynamic simulation of the subsystems for classical, normal motion can be switched. Following the interpretation of the results, the initial parameters of the biomechanical subsystems may be modified. In the next phase, the components of the subsystems are divided successively and the finite element structure is obtained for the entire biomechanical system of the joints that participate in human locomotion.
(1) Introduction: The changes in the joint morphology inevitably lead to prosthesis, but the hip pathology is complex. The hip arthroplasty is a therapeutic solution and can be caused, most frequently, by primary and secondary coxarthrosis due to or followed by traumatic conditions. The main aim of this study was to find the method of revision hip prosthesis that preserves as much bone material as possible and has sufficiently good mechanical strength. (2) Materials and Methods: In this study, in a first step, the two revision prostheses were performed on bone components taken from an animal (cow), and then, they were tested on a mechanical testing machine until the prostheses physically failed, and the force causing their failure was determined. (3) Results: These prostheses were then modelled in a virtual environment and tested using the finite element method (FEM) in order to determine their behaviour under loading from normal human gait. Displacement, strain, and stress maps were obtained. (4) Discussion: Discussions on hip revision prostheses, method, and theory analysis are presented at the end of the paper. (5) Conclusions: Important conclusions are drawn based on comparative analyses. The main conclusion shows that the both orthopaedic prostheses provide a very good resistance.
The paper first presented the stages of obtaining a virtual model of a female patient, aged 13 years and who had multiple dental malpositions. The patient underwent a CT scan, and CT images were initially processed using the InVesalius program and three-dimensional geometries were obtained, both for the mandible and jaw, but also for the dental structure. These primary geometries were processed, edited and transformed using Reverse Engineering techniques in the Geomagic program. Dental alveoli were obtained in SolidWorks using CAD methods and techniques. Bracket elements and orthodontic wires were also generated in SolidWorks. Interference solids have been removed by various processes so that the model is geometrically accurate. Finally, these structures formed of virtual solids recomposed the orthodontic system of the analyzed patient. The custom model was exported to Ansys, where it was analyzed and result maps were obtained. Finally, interesting conclusions and some clinical observations were highlighted.
In order to obtain a personalized three-dimensional model of a patient based on CT images, the InVesalius program was initially used, which performs the initial conversion of the analyzed tissues into a specific engineering file composed of the so-called "point cloud". This "point cloud" was imported into the Geomagic program, in which, using reverse engineering techniques, the "point cloud" was initially transformed into elementary triangular surfaces. These primary geometric structures have been edited, transformed, adapted so that, in the end, perfectly closed surfaces are obtained. It was done in this way, both for the bone structure of the head, but also for the dental structure. These complex geometries were loaded into SolidWorks, where they were originally transformed into virtual solids. These geometric structures were loaded and assembled into SolidWorks and interference solids were removed. Finally, a customized three-dimensional model was obtained on which different normal or pathological situations can be analyzed using kinematic simulations or using the finite element method.
In a postmodern world which is extremely dynamic and anchored in a communication that requires online accesses in almost all fields, the training and preparation of young generations is required to be carried out in such a way that the acquisition of practical skills should be reflected in their future activities. Along with the other forms of training, physical training is a defining part of those who are part of the military environment. There are various aspects when, in the lives of the military, physical training can influence the course of their military career. Moreover, the motivations of behavioral changes, either inner or external, can cause increased attention to this type of training. Military physical training is a stand-alone activity in the military environment, a basic component of military training programs. We will also highlight physical training through its importance in the context of preparing the military for participation in theatres of operations, facilitating the understanding of its role in modern conflicts and the support it can offer in achieving military tasks and objectives. Moreover, an advanced level of physical training will lead to the maximization of the psycho-moral and physical components of the combative capacities, will support the improvement and maintenance of general physical and mental health and will help to develop the capacity for resistance to stress conditions such as fatigue, fear, panic, hunger etc.
Coxofemoral osteoarthritis is a common pathology, especially for the elderly or for certain social categories. One solution to this medical problem is the hip joint prosthesis. This, however, over time, can lead to joint damage, and obviously a revision of the prosthesis is required. The revision hip prosthesis presents additional mechanical elements and obviously different surgical techniques are required compared to the normal hip prosthesis. There are several methods of prosthesis and obviously more surgical techniques. We were interested to identify that revision method that retains as much bone material, and which has the same mechanical strength. A special device designed to test the revision hip prosthesis was designed and made using a cow's pelvis as bone material. The orthopedic assembly is attached to the device and supposed to a progressive loading until it mechanically fails. The orthopedic system was analyzed with a microscope where the cracks that determined the mechanical failure of the orthopedic system were detected and measured. In parallel, the same device is loaded into a virtual test environment and subjected to a similar load. The actual results and those obtained in the virtual environment were compared and analyzed. Finally, interesting conclusions were drawn.
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