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.

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.

The main objective of this research was to propose a light and practical design solution for electric bike front drive with bottom bracket electric motor. The initial design needs to be redesigned so it can enable simultaneous use of the electric drive and pedal drive, with integration of the front gear shifter. After gathering the basic information linked to the problem and inspecting the initial design solution, the assets and flaws have been identified. The CAD models of the considered possible solutions were developed into FEM models which were used for structural analysis in CAD/CAE software system CATIA. On the basis of the FEM analysis and additional criteria, the optimal solution was chosen, and structural optimization, based on FEM model, was performed. A prototype was manufactured and a mounting process in a place of the initial design was performed. Afterwards, electric bike with mounted prototype was tested under real conditions.

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.

This paper investigated the effect of the tenon length on the strength and stiffness of the standard mortise and tenon joints, as well of the double mortise and tenon joints, that were bonded by poly(vinyl acetate) (PVAc) and polyurethane (PU) glues. The strength was analyzed by measuring applied load and by calculating ultimate bending moment and bending moment at the proportional limit. Stiffness was evaluated by measuring displacement and by calculating the ratio of applied force and displacement along the force line. The results were compared with the data obtained by the simplified static expressions and numerical calculation of the orthotropic linear-elastic model. The results indicated that increasing tenon length increased the maximal moment and proportional moment of the both investigated joints types. The analytically calculated moments were increased more than the experimental values for both joint types, and they had generally lower values than the proportional moments for the standard tenon joints, as opposed to the double tenon joints. The Von Mises stress distribution showed characteristic zones of the maximum and increased stress values. These likewise were monitored in analytical calculations. The procedures could be successfully used to achieve approximate data of properties of loaded joints.

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.

Polycrystalline advanced ceramics are synthetic products produced by sintering together selected ceramics grains in a metal matrix serving as a binder. In order to be able to propose their optimisation, achieving high performance cutting and leading to reduced operating costs and improved working environment, relevant fracture mechanisms involved in their failure need to be determined. In this work, experimental results of plane strain fracture toughness obtained earlier on single-edge-V-notched-beam specimens were supported with microscopy analysis. These findings establish a clear connection between the fracture toughness results and the fracture mechanisms visible on and beneath the fracture surfaces, revealing adiabatic conditions that occur at the crack tip during fracture.

ABSTRACT Polycrystalline advanced ceramics are composite materials produced by the reaction of tungsten metal powder and carbon powder in a metal binder at temperatures of 1,400-1,500°C. This process enables them a high hardness and abrasion resistance in all directions. The mode I fracture behaviour of single-edge-V-notched-beam specimens was investigated as a function of loading rate and temperature. A series of tests was conducted and plane strain fracture toughness values were determined at a range of loading rates and temperatures, as those in real operating conditions. These experimental results reveal a fracture mechanism establishing a clear connection between the fracture toughness results and the mechanisms causing fracture to happen.

This article has been retracted at the request of the Editor-in-chief. After a thorough investigation, the Editor has decided to retract this manuscript due to double submission.   ABSTRACT Polycrystalline advanced ceramics are synthetic products produced by sintering together selected ceramics grains in a metal matrix serving as a binder. In order to be able to propose their optimisation, achieving high performance cutting and leading to reduced operating costs and improved working environment, relevant fracture mechanisms involved in their failure need to be determined. In this work, experimental results of plane strain fracture toughness obtained earlier on single-edge-V-notched-beam specimens were supported with microscopy analysis. These findings establish a clear connection between the fracture toughness results and the fracture mechanisms visible on and beneath the fracture surfaces, revealing adiabatic conditions that occur at the crack tip during fracture.

In this paper, an analytical calculation of load on bridge crane carts winch wheel loads was performed based on which FEM analysis and topological wheel optimization were performed. After the calculation, a standard wheel diameter was adopted. During FEM analysis in the CAD system, SolidWorks noted that certain surface areas had extremely low stress values, which was the main reason for the topological optimization of the wheel. The topological optimization of the geometric 3D model of the wheel is made in the CAESS ProTOp software, resulting in optimized 3D geometric wheel model. These models offer a number of advantages, such as saving materials to produce, reducing their own weight, balance stress conditions and easy customization model optimized technologies of additive manufacturing. This model of analysis and optimization was performed on the laboratory model of the bridge crane and it is applicable to all types of cranes.