Optimization of Traceability in Conditions of the Company

Import 05/08/2014Cílem diplomové práce je úspěšné řešení projektu zavádění traceability v podmínkách dané firmy. Mezi další cíle patří zajištění bezproblémového chodu celého projektu, vytvoření metodiky pro práci s označenými materiály a plné využití softwarového řešení ve výrobě. Součástí práce je teoretická část, která obsahuje a vysvětluje základní pojmy, které jsou dále používány. Náplní praktické části je analýza současného stavu a její vyhodnocení, návrhy řešení a vyhodnocení celkových přínosů práce včetně ekonomického dopadu.Successful solution of implementation of traceability in conditions of company project is an objective of diploma thesis. Ensuring problem-free working of the project, establishment of methods for working with marked materials and full utilization of software solution in production are next objectives of the thesis. Theoretical part includes and explains basic terms, which I work with. Practical part includes analysis of the current condition and its evaluation, economical impact included.345 - Katedra mechanické technologievýborn

Comprehensive view of topological optimization scooter frame design and manufacturing

The combination of topology optimization (TO) and 3D printing has revolutionized the way components are designed and fabricated. In view of this, this manuscript presents a TO workflow considering the frame of a scooter. In particular, TO is employed to redesign the scooter frame based on a commercial one. The topologically optimized frame is then fabricated with stainless steel 316L utilizing the selective laser melting (SLM) method. In particular, technical obstacles encountered during the process and according solutions are recorded. Given the herein notes, readers who are working with the two technologies can anticipate the technical problems and deliver more effective solutions should any of them arise.Web of Science137art. no. 120

Residual stress build-up in aluminum parts fabricated with SLM technology using the bridge curvature method

In metal 3D printing with Selective Laser Melting (SLM) technology, due to large thermal gradients, the residual stress (RS) distribution is complicated to predict and control. RS can distort the shape of the components, causing severe failures in fabrication or functionality. Thus, several research papers have attempted to quantify the RS by designing geometries that distort in a predictable manner, including the Bridge Curvature Method (BCM). Being different from the existing literature, this paper provides a new perspective of the RS build-up in aluminum parts produced with SLM using a combination of experiments and simulations. In particular, the bridge samples are printed with AlSi10Mg, of which the printing process and the RS distribution are experimentally assessed with the Hole Drilling Method (HDM) and simulated using ANSYS and Simufact Additive. Subsequently, on the basis of the findings, suggestions for improvements to the BCM are made. Throughout the assessment of BCM, readers can gain insights on how RS is built-up in metallic 3D-printed components, some available tools, and their suitability for RS prediction. These are essential for practitioners to improve the precision and functionality of SLM parts should any post-subtractive or additive manufacturing processes be employed.Web of Science1517art. no. 605

Stochastic evaluation of cutting tool load and surface quality during milling of HPL

The topic of the article concerns the mechanics of machining plastics and their machined surface. This article deals with measurements and their stochastic (probabilistic) evaluation of the force and moment loading of the machine tools and workpiece. It also deals with the quality of the machined surface in relation to its surface roughness and surface integrity. Measurements were made under different cutting conditions on a CNC milling machine using a newly designed cutter with straight teeth. The statistical evaluation is presented by bounded histograms and basic statistical characteristics that give a realistic idea of the machining process. The practical focus of the experiments is on the milling of HPL (high-pressure plastic-laminate composite material). The listed procedures can also be applied to other materials and machining methods, and can be used for numerical modelling, setting the optimum parameters of machining technology, or for the design of cutting tools. Numerical modelling and other solution options are also mentioned. We have not yet found detailed information in the literature about the milling of HPL material, and our results are therefore new and necessary.Web of Science1224art. no. 1252

Numerical analysis of the calcaneal nail C-NAIL

The presented article investigates the biomechanics of the calcaneal nail C-NAIL (TM) by numerical calculations and, partially, experimentally. This nail is widely used in trauma and orthopaedics. A numerical model of implants directly interacting with the bone tissue model obtained from CT scans was calculated. The material properties of the bone tissue can be described by several models; in this work, a non-homogeneous material model with isotropic elements and prescribed elastic modulus was used to provide a more accurate model of the applied force distribution on the individual parts of the implants. The critical areas of the nail and its fixtures were investigated using finite element strength calculations to verify their strength and reliability, contributing to the safety and faster and easier treatment of patients. These analyses suggest that the strength of the calcaneal nail C-NAIL, as well as the stabilization of bone fragments resulting from its use, are sufficient for clinical practice.Web of Science1210art. no. 526

Analytical, stochastic and experimental solution of the osteosynthesis of the fifth metatarsal by headless screw

This paper evaluates the various approaches to strength and stiffness analysis of fracture osteosynthesis using a headless Herbert screw. The problem has been extensively addressed using several scientific approaches, namely the analytical approach, stochastic approach, experimental approach, and (marginally) using the finite elements method. The problem is illustrated on the use of a prototype headless screw Ti: 4.0/1.4 x 30/7 (manufacturer: Medin, Czech Republic) and the surgical treatment of the fifth metatarsal fracture. Mathematical equations for the analytical calculation of the maximum stresses in the screw were established for tensile/compression loading. This problem is also interesting because of its static indetermination in tension and compression; for this reason, it was necessary to use the deformation condition, i.e., the relationship between screw extension and bone contraction. The stochastic (probabilistic) approach, i.e., application of the Monte Carlo method, takes advantage of the mathematical equations derived during the analytical solution by respecting of the natural variabilities and uncertainties. The analytical and stochastic approaches were validated by measurements on porcine bones and by the finite element method. The data measured experimentally were also processed and used for deriving an equation, appropriately approximating the data. The main part of the measurement was to determine the axial force generated during osteosynthesis with a headless screw. The obtained compressional force was used to determine the maximal stress in the screw and bone. Finally, the methods were compared. In this paper, comprehensive and original approaches based on the authors' experience with multiple methods are presented. Obtained results are necessary for headless screw designers during optimalization of the implants and are also useful for surgeons developing new surgical techniques. This biomechanical problem was solved in cooperation with the engineering industry and physicians to improve the quality of care for patients with trauma in orthopedics and surgery.Web of Science1219art. no. 961

Mechanics of screw joints solved as beams placed in a tangential elastic foundation

This article deals with a new original analytical solution of deformation, force and stress states in wood screw joints up to the limit values of pulling out/breaking the screw. The screws are under tension. The wood-to-screw interaction is effectively simplified by introducing several physical model variants using a tangential elastic non-linear foundation. The experimental verification of the proposed models using pull-out tests (i.e., pulling out screws from dry spruce wood in laboratory conditions) confirms the correctness of the proposed models of the elastic linear/non-linear foundation. The validity of the model is also analytically and experimentally verified in the biomechanical model of pulling out screws from the femur of a bovine/human cadaver, which confirms and expands the validity of newly designed screw joint models outside the timber structure area.Web of Science1112art. no. 561

Biomechanical assessment of cannulated nails for the treatment of proximal femur fractures

This article focuses on a type of surgical implant used in orthopaedics and traumatology-cannulated femoral nails. Femoral nails are used in medical treatment for purposes of osteosynthesis, i.e., when treating various types of complicated fractures, in this case fractures of the femur. The article investigates cases in which a nail has been implanted in the proximal part of the femur for a short time (with the fracture still not healed), compared with cases in which the bone has already healed. According to AO classification, examined fractures are described as AO 31B3 AO 32A3. The main focus is on strength-deformation analysis using the finite element method (FEM), which makes it possible to determine the behaviour of the femur-implant system. FEM analysis was used to compare 1.4441 steel nails made by two manufacturers, Medin (Czech Republic) and Tantum (Germany). Boundary conditions including external loading, prescribed supports and elastic foundation are defined. There were solved FEM analyses for five cases of healed femur and five cases of broken femur both including implants with prescribed collo-diaphyseal angles. The results of the analysis were used to assess stress-deformation states from the perspective of appropriateness for clinical treatment, biomechanical reliability and safety. All examined femoral nails are compared, safe and suitable for patient treatment.Web of Science1215art. no. 747

Inventory Management

Import 03/08/2012Cílem bakalářské práce je zlepšení systému řízení zásob ve skladu, který je podpůrnou jednotkou servisní opravny nákladních automobilů. Mezi další cíle práce patří snížení nákladů na dopravu náhradních dílů a co největší eliminace časových prodlev, které by mohly ohrozit provoz firmy. Součástí práce je teoretická část, která obsahuje a vysvětluje základní pojmy, s nimiž je dále pracováno. Praktická část pak obsahuje informace o vnitřní struktuře firmy a další potřebné informace, které jsou nutné pro zpracování návrhů řešení.Improvement of system of an inventory management in the warehouse is the objective of bachelor thesis. Warehouse is support unit of truck - repair shop. Utmost elimination of time delays, reduction of transport costs which can endanger working are other objectives of thesis. Theoretical part includes and explains basic terms, which I work with. Practical part includes all information about inner structure of company and next needed information, which are necessary for processing suggestions of solution.345 - Katedra mechanické technologievýborn

Fire sport and its training

Objectives: The main objective of this work is to characterized fire sport in details and create a list of particular exercises aim to help in training in two fire sport disciplines. This sport is continually developing and is suitable for people of almost any age. The complex of exercises designated for the 100 m sprint with hurdles and for the climb to training tower's 4th floor with hook shaped ladder represents also means of training the fitness condition needed for other fire sport disciplines. Methodology: Collecting data from literature, coaches, sportsmen and its subsequent theoretical processing. Results: The result of this work is fire sport overall history and development. Introduction of particular disciplines and material equipment. Demonstration of training sessions in various part of yearly training cycle, formation of exercise collection with theirs description and usage in the training cycle. Exercise collection contains 11 exercises for running the 100m hurdles and 18 exercises for output to 4 floor training tower displayed on kinograms. A 22 modified exercises for the 100m hurdles and 18 for output to the tower. Key words: fire sport, special exercises, fitness trainin