DOAJ (DOAJ: Directory of Open Access Journals), Nov 1, 2015
This paper describes a structural analysis of the CAD model three versions fixators Sarafix which... more This paper describes a structural analysis of the CAD model three versions fixators Sarafix which is to explore the possibility of introducing composite materials in the construction of the connecting rod fixators comparing values of displacement and stiffness at characteristic structure points. Namely, we have investigated the constructional performance of fixators Sarafix with a connecting rod formed from three different composite materials, the same matrix (epoxy resin) with three different types of fibers (E glass, kevlar 49 and carbonM55J). The results of the structural analysis fixators Sarafix with a connecting rod made of composite materials are compared with the results of tubular connecting rod fixators made of stainless steel. After comparing the results, from the aspect of stiffness, we gave the final considerations about composite material which provides an adequate substitution for the existing material.
This paper presents a comparative analysis of the biomechanical characteristics of an external fi... more This paper presents a comparative analysis of the biomechanical characteristics of an external fixator with a frame made of two different materials (stainless steel and composite material) during anterior-posterior bending. Before the test itself, two representative configurations of the Sarafix fixator were selected for application on the lower leg and upper extremities under the designations B50 and C50, which are most widely used in orthopedic practice. The examination of the biomechanical characteristics of the external fixator was carried out using the structural analysis of the construction performance of the Sarafix fixator using the finite element method, the results of which were verified through experimental tests. The developed experimental and FEM models study the movement of the fracture crack and enable the determination of the stiffness of structural designs as well as the control of the generated stresses at the characteristic locations of the fixator. The results show that the fixator with a carbon frame has lower stresses at critical points in the construction compared to the fixator with a steel frame, in the amount of up to 49% (at the measuring point MT+) or up to 46% (at the measuring point MT-) for both fixture test configurations. The fixator with a carbon frame has greater displacements at the fracture site compared to the fixator with a steel frame, in the amount of up to 45% (for configuration B50) or up to 31% (for configuration C50). The stiffness of the structure for both test configurations of the fixator is lower in the fixator with a carbon frame compared to the fixator with a steel frame by up to 27%. Based on the findings of this study, we can conclude that a fixator with a steel frame has better biomechanical characteristics compared to a carbon frame.
Numerical and Experimental Stress Analysis of a Thin-Walled Cylindrical Tank with a Flat Bottom
Lecture notes in networks and systems, 2021
Methodology for design of a thin-walled cylindrical thank with a flat bottom is presented in this... more Methodology for design of a thin-walled cylindrical thank with a flat bottom is presented in this paper. Except design, methodology for analytical, numerical and experimental analysis of stresses on the thank is also presented. After analytical calculations, geometrical modeling is carried out using CAD/CAM/CAE system CATIA. Distribution and values of principal strains and stresses are presented. Mathematical and numerical model is developed for linear elastic and isotropic material. In addition, introduction is given for theory of stresses for thin-walled thanks. For numerical structural analysis finite element method is used. Experimental stress analysis is carried out by tensometric measuring. Comparison of results from analytical, numerical and experimental analysis a predominantly good agreement with certain deviations can be found. Based on the comparison of the results obtained using analytical calculation, numerical method and experiment, a good match of the results can be observed. By comparing the results, the FEM model was verified.
Advances in Science and Technology Research Journal, Aug 16, 2023
The aim of this work is to investigate the impact of geometry on the mechanical stability of char... more The aim of this work is to investigate the impact of geometry on the mechanical stability of characteristic structural solutions of plates for internal bone fixation using the finite element method (FEM). Based on the realistic construction of plates for internal bone fixation, 3D geometric and FEM models were formed, and then structural analysis was carried out in the CAD/CAE system CATIA V5. Five different types of plates for internal bone fixation were tested under two types of loads: axial pressure and torque in the case of application to the femur. During the structural analysis, stresses and displacements were monitored at characteristic points of the structure. The most attention was paid to the relative displacements of the bone model fragments, because the stiffness of the plates for the internal fixation of the bone was determined based on them. At the end of the paper, the results of all analyzed plates are presented, their mutual comparison as well as the conclusion in which, based on everything done, it was stated which plate would be the most favorable solution for a given case of bone fracture.
Advances in Science and Technology Research Journal
The paper analyzes the stiffness of the Orthofix external fixation system at axial pressure load,... more The paper analyzes the stiffness of the Orthofix external fixation system at axial pressure load, applied to the lower leg in case of an unstable fracture. Based on the actual construction of the Orthofix fixator, its 3D model was formed, and then a structural analysis was performed in the CATIA V5 software system. The aim of this paper is to investigate the mechanical properties of Orthofix fixator. FEM analysis of the fixator revealed displacements at characteristic points of the structure and fractures. During the FEM analysis, it is possible to change the load values, all with the aim of obtaining the best possible information about the behavior of the fixator during installation and use by the patient. Based on the results obtained from the FEM analysis, it can be concluded that the Orthofix fixative shows very good stiffness, but also that it can be improved by using newer materials, such as composite or some alloys of titanium and aluminum.
Advances in Science and Technology Research Journal, Jun 1, 2023
Analysis of mechanical properties of external unilateral fixation device "Ultra X", in the case o... more Analysis of mechanical properties of external unilateral fixation device "Ultra X", in the case of torque load, is presented in this paper. Fixation device is applied on lower leg in the case of unstable fracture. Computer aided design (CAD) model and finite element model (FEM) are developed according to the dimensions and material properties of real fixation device. In the next step principal stress and deformation analysis is performed in CATIA V5 software. During numerical analysis values of stresses at critical places are monitored and analyzed. In addition, values of displacements are measured on important places on fixation device and bone fracture. Using values of displacements at the place of bone fracture, stiffness of the fracture is calculated. The same methodology is used to calculate stiffness of the fixation device. Using obtained results, several conclusions about the mechanical properties of the fixation device "Ultra X" are formulated at the end of the paper.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
In this research, an analysis of the mechanical behaviour for the Orthofix external fixation devi... more In this research, an analysis of the mechanical behaviour for the Orthofix external fixation device under the impact of torque was performed. Research considers application of the Orthofix device on the tibia bone for the case of unstable fracture. 3D (Three Dimensional) model of the Orthofix device was created in the CATIA (Computer Aided Three-Dimensional Interactive Application) software, based on the real device construction. Structural analysis was used to monitor and analyse the stress magnitudes on the specific areas of the fixation device and fracture. With usage of the interfragmentary displacement data for the bone fragments, degrees of stiffness are introduced for the fracture and fixation device. Obtained results are used to specify the mechanical behaviour of the Orthofix fixation device.
Advances in Science and Technology Research Journal
Analysis of mechanical stability for external fixation device Orthofix in the case of anterior-po... more Analysis of mechanical stability for external fixation device Orthofix in the case of anterior-posterior bending is carried out in this paper. Device is applied to the lower leg for the case of unstable fracture. Real device is measured and 3D CAD model is developed. CAD model is used for numerical structural stress analysis which is carried out using CATIA V5 software. Results for displacements are obtained for selected critical places on the device and for the place of fracture. In addition, values of principal and von Misses stresses are obtained and analyzed. Using obtained results, conclusions about mechanical stability of device are formulated.
A quality constructive solution can be considered one that ensures the proper functioning and rel... more A quality constructive solution can be considered one that ensures the proper functioning and reliability of the product with the least possible cost. Therefore, it is the main goal of every designer to obtain the required girder capacity with minimal material expense in the cross section design of a full plate girder. This ensures an optimal material participation in the overall price of the finished structure already in the initial stage of design. This paper presents the I-profile shape cross-section optimization at the overhead crane main girder, where the metal sheets stability calculation to buckling is made according to BAS/JUS U.E7.121/1986. The mathematical model is solved using the nonlinear programming method SUMT (sequential unconstrained minimization technique) where from the goal function with constraints, with introduction of the penalty function, a new function
This paper describes comparative analysis of the biomechanical performances conducted on the exte... more This paper describes comparative analysis of the biomechanical performances conducted on the external fixation devices whose frames are made out of two different material (stainless steel and composite material). Biomechanical properties were determined with experimental and FEM (finite element method) models which are used to study the movement of the fracture crack, establish stiffness of the design solutions and monitor generated stresses on the zones of interest. Geometric modeling of two fixation devices configurations B50 and C50 is used as a basis for structural analysis under the impact of axial load. Structural analysis results are confirmed with an experimental setup. Analyzed deflection values in the load and fracture zones are used to define the exact values of the stiffness for the construction design and fracture, respectively. The carbon frame device configuration has 28% lower construction stiffness than the one with the steel frame (for B50 configuration), i.e., 9% ...
Proceedings of the 32nd International DAAAM Symposium 2021, 2021
Continuous measurement of black carbon (BC) concentrations in ambient air was performed using the... more Continuous measurement of black carbon (BC) concentrations in ambient air was performed using the optical-based instrument called aethalometer. The attenuation of light by BC was measured at 7 different wavelengths. This gives not only the pure concentration of BC in the ambient air but also dependence of attenuation on the wavelength of light, from which the Angstrom exponent can be derived. Based on the Angstrom exponent, we can estimate the percentage of BC that originates from solid fuel (wood and coal burning) or liquid fuel (diesel). Thus, a simple source apportionment analysis is presented.
Periodicals of Engineering and Natural Sciences (PEN)
The paper shows a comparison of the three different methods to determine stress and strain in a U... more The paper shows a comparison of the three different methods to determine stress and strain in a U-shaped pipe compensator which is used to decrease stress in long pipes due to the constrained temperature dilatations. The stress and strain are analyzed analytically first with some parts of the analytical solution obtained numerically, such as integrals with no analytical solution in a closed form, i.e., functional series can be involved as a tool to solve those integrals. The pipe is analyzed as a beam or a planar frame using the Castigliano's method to determine displacements. Since there are curved parts of the U compensator, the curved beam theory is applied. The alternative method to determine the strains and stresses along the pipe is shown using the numerical simulations in SolidWorks. The results are compared with the analytical solution. Finally, the experimental method using a 3D scanner is involved for a comparison to check the applied conditions in the analytical and the simulation model.
There is a lot of papers concerning gears topology optimization, but all of them are limited to t... more There is a lot of papers concerning gears topology optimization, but all of them are limited to the topology optimization of gear body. Gear tooth is not taken into consideration so far. Gear tooth was not optimized before because optimised structure could not be produced. By advancing of additive manufacturing technology, now, gear tooth can be produced in a form of shell body with empty space inside. In this paper, mass of spur gear tooth is optimized in relation to Von- Misses stress on critical places on the gear tooth. Optimization goal is to find optimal shell thickness of shell body spur gear tooth. Keywords –Spur gear tooth, topology, optimization, shell thickness, additive manufacturing.
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