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.

The paper explores importance of rapid prototyping technology, as an important part of Industry 4.0, in product development and design process. Current state of this technology is explored in detail, with special focus of places and processes where this technology plays important role inside Industry 4.0. Paper answers several questionssuch as: does this technology have its future inside Industry 4.0, is this technology integral part of Industry 4.0 or just one aspect, has the time come to call this technology rapid manufacturing (of final products) instead of rapid prototyping (of prototypes)?Industry 4.0 implies rapid prototyping of final products, not only its prototypes. Main representative of rapid prototyping technology is additive manufacturing. Today, additive manufacturing technologies do not only serve for prototyping. They are becoming increasingly used for manufacturing of final fully functional products. Product development and design process inside Industry 4.0 must be adopted to new market demands which implies fast development and design and fast manufacturing. The time from initial concept design to the final product manufacturing must be as short as possible. The paper provides answers to the above stated questions. In addition, real examples of product development and design of prototypes and real fully functional products are presented, with a special focus on products and prototypes developed in Bosnia and Herzegovina.

The goal of this research is development, design and manufacturing of CNC milling machine prototype using standard aluminium profiles. Machine is a three axis’s machine and it is developed primarily for education in the field of wood machining. It can be used also for machining of light metal parts. Main initial goal of the machine development was the low cost for its manufacturing. To achieve this goal, rapid prototyping technology was used to manufacture most of the machine parts. In addition, a lot of standard parts are used. The detail methodology for machine development, design and manufacturing are shown in this paper. Design process includes development of CAD models, calculation of all necessary critical parts, selections of materials and development of machine subassemblies and assemblies.

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% (for C50 configuration). In addition, fracture stiffness values for the composite frame application are approximately 23% lower (B50 configuration), i.e., 13% lower (C50 configuration), compared to steel frame. The carbon frame device has about 33% lower stresses at the critical zones compared to the steel frame at the control zone MM+ and, similarly, 35% lower stresses at the control zone MM-. With an exhausting analysis of the biomechanical properties of the fixation devices, it can be concluded that steel frame fixation device is superior, meaning it has better biomechanical characteristics compared to carbon frame fixation device, regarding obtained data for stresses and stiffnesses of the frame construction and fracture. Considering stresses at the critical zones of the fixation device construction, the carbon frame device has better biomechanical performances compared to steel frame devices.

This paper presents the development and implementation of integrated intelligent CAD (computer aided design) system for design, analysis and prototyping of the compression and torsion springs. The article shows a structure of the developed system named Springs IICAD (integrated intelligent computer aided design). The system bounds synthesis and analysis design phases by means of the utilization of parametric 3D (three-dimensional) modeling, FEM (finite element method) analysis and prototyping. The development of the module for spring calculation and system integration was performed in the C# (C Sharp) programming language. Three-dimensional geometric modeling and structural analysis were performed in the CATIA (computer aided three-dimensional interactive application) software, while prototyping is performed with the Ultimaker 3.0 3D printer with support of Cura software. The developed Springs IICAD system interlinks computation module with the basic parametric models in such a way that spring calculation, shaping, FEM analysis and prototype preparation are performed instantly.

The development process of the knowledge-based engineering (KBE) system for the structural size optimization of external fixation device is presented in this paper. The system is based on algorithms for generative modeling, finite element model (FEM) analysis, and size optimization. All these algorithms are integrated into the CAD/CAM/CAE system CATIA. The initial CAD/FEM model of external fixation device is verified using experimental verification on the real design. Experimental testing is done for axial pressure. Axial stress and displacements are measured using tensometric analysis equipment. The proximal bone segment displacements were monitored by a displacement transducer, while the loading was controlled by a force transducer. Iterative hybrid optimization algorithm is developed by integration of global algorithm, based on the simulated annealing (SA) method and a local algorithm based on the conjugate gradient (CG) method. The cost function of size optimization is the minimization of the design volume. Constrains are given in a form of clinical interfragmentary displacement constrains, at the point of fracture and maximum allowed stresses for the material of the external fixation device. Optimization variables are chosen as design parameters of the external fixation device. The optimized model of external fixation device has smaller mass, better stress distribution, and smaller interfragmentary displacement, in correlation with the initial model.

The main objective of this research is to establish a connection between orthodontic mini-implant design, pull-out force and primary stability by comparing two commercial mini-implants or temporary anchorage devices, Tomas®-pin and Perfect Anchor. Mini-implant geometric analysis and quantification of bone characteristics are performed, whereupon experimental in vitro pull-out test is conducted. With the use of the CATIA (Computer Aided Three-dimensional Interactive Application) CAD (Computer Aided Design)/CAM (Computer Aided Manufacturing)/CAE (Computer Aided Engineering) system, 3D (Three-dimensional) geometric models of mini-implants and bone segments are created. Afterwards, those same models are imported into Abaqus software, where finite element models are generated with a special focus on material properties, boundary conditions and interactions. FEM (Finite Element Method) analysis is used to simulate the pull-out test. Then, the results of the structural analysis are compared with the experimental results. The FEM analysis results contain information about maximum stresses on implant–bone system caused due to the pull-out force. It is determined that the core diameter of a screw thread and conicity are the main factors of the mini-implant design that have a direct impact on primary stability. Additionally, stresses generated on the Tomas®-pin model are lower than stresses on Perfect Anchor, even though Tomas®-pin endures greater pull-out forces, the implant system with implemented Tomas®-pin still represents a more stressed system due to the uniform distribution of stresses with bigger values.

This study investigated the correlation between bone characteristics, the design of orthodontic mini-implants, the pull-out force, and primary stability. This experimental in vitro study has examined commercial orthodontic mini-implants of different sizes and designs, produced by two manufacturers: Tomas-pin SD (Dentaurum, Ispringen, Germany) and Perfect Anchor (Hubit, Seoul, Korea). The total number of 40 mini-implants were tested. There are two properties that are common to all tested implants—one is the material of which they are made (titanium alloy Ti-6Al-4V), and the other is the method of their insertion. The main difference between the mini-implants, which is why they have been selected as the subject of research in the first place, is reflected in their geometry or design. Regardless of the type of implant, the average pull-out forces were found to be higher for a cortical bone thickness (CBTC) of 0.62–0.67 mm on average, compared to the CBTC < 0.62 mm, where the measured force averages were found to be lower. The analysis of variance tested the impact of the mini-implant geometry on the pull-out force and proved that there is a statistically significant impact (p < 0.015) of all three analyzed geometric factors on the pull-out force of the implant. The design of the mini-implant affects its primary stability. The design of the mini-implant affects the pulling force. The bone quality at the implant insertion point is important for primary stability; thus, the increase in the cortical bone thickness increases the value of the pulling force significantly.

Car jack is the basic equipment of every car. To replace the tires or to repair a specific defect on the car it is necessary to have a car jack. A modern way of creating the complex mechanical structures is described in this paper, which allows for rapid change of parameters and therefore of the whole design, i.e. the parameterized car jack model was developed. Also, the goal of this research is to carry out kinematic analysis of a car jack design. Parametric model is developed in such a way that all parameters of design are in correlations to one main parameter. The angle of thread spindle is chosen for main parameter. Usually, main parameter should be chosen as one of the parameters from power input elements. Car jack has a human hand power which is applied on car jack handle and because of that, the angle of rotation of thread spindle is the best for main parameter.

This paper presents the methodology for the development of an optimization model for the optimization of the cross-section dimensions of a bridge crane girder designed as a welded I-profile. To carry out this optimization, the CAD/CAE software package CATIA V5 was used. In order to develop an optimization model, a CAD geometrical model and structural analysis model were developed. Optimization was carried out by the iterative method using a simulated hardening algorithm. Additionally, the optimization process is carried out by using the PEO (Product Engineering Optimization) CATIA module that contains tools for setting the optimization criteria, design parameters, constraints, and algorithms. The goal of the optimization is to achieve the minimal mass of the girder, while satisfying all functional and geometrical constraints. As a result of the optimization process, minimal girder dimensions were obtained and due to that, a minimal amount of material can be used for the manufacturing of the girder.

Structural size optimization of a device for external bone fixation within a formed iterative hybrid optimization algorithm was presented in this paper. The optimization algorithm was in interaction with the algorithms for generative design and FEM analysis and completely integrated within CATIA CAD/CAM/CAE system. The initial model, representing the current design of the bone external fixation device Sarafix, was previously verified by experimental testing. The formed hybrid optimization algorithm was created as an integration of the global (SA method) and local (CG method) algorithm. The constraints of the optimization model are the clinical limitations of the interfragmentary displacements and the material strength. The optimized design has less weight, greater rigidity and less transverse interfragmentary displacements at the point of fracture compared to the current design.

This paper presents the development and experimental verification of a generative CAD/FEM model of an external bone fixation device. The generative CAD model is based on the development of a parameterized skeleton algorithm and sub-algorithms for parametric modeling and positioning of components within a fixator assembly using the CATIA CAD/CAM/CAE system. After a structural analysis performed in the same system, the FEM model was used to follow interfragmentary fracture displacements, axial displacements at the loading site, as well as principal and Von Mises stresses at the fixator connecting rod. The experimental analysis verified the results of the CAD/FEM model from an aspect of axial displacement at the load site using a material testing machine (deviation of 3.9 %) and the principal stresses in the middle of the fixator connecting rod using tensometric measurements (deviation of 3.5 %).The developed model allows a reduction of the scope of preclinical experimental investigations, prediction of the behavior of the fixator during the postoperative fracture treatment period and creation of preconditions for subsequent structural optimization of the external fixator.