Materials Science Forum Vol. 919

Abstract: The capability periodically to store and release the latent heat of phase transition during melting and solidification of Phase Change Materials (PCMs) has been currently the main subject of interest with regard to cost reduction efforts for cooling, heating of interiors and Domestic Hot Water (DHW) necessary for the operation and maintenance of adequate thermal comfort in new modern as well as old renovated residential buildings. The main principle of PCMs facilities to reduce significantly the energy consumption in the building industry of the future is based on the ability of thermo-active heat exchangers to absorb and later to dissipate into the surroundings excessive heat which can be easily obtained from renewable sources (e.g. solar energy, geothermal heat, etc.) directly in a building or in its immediate vicinity. Smart interior tiling and furnishing systems can provide high energy efficiency by stabilizing the room temperature at a level ensuring sufficient thermal comfort basically governed by the thermal conductivity and heat exchange area between ceiling (respectively also wall and floor if necessary) heat exchangers (radiators) and the heat storage medium in the form of PCMs. Unfortunately, most conventional building materials, e.g. aerated concrete, bricks, gypsum, ceramic tiles, etc. are particularly characterized by very low thermal conductivity, which disadvantages them to be used for these purposes. However, highly porous metallic material such as aluminium foam prepared by powder metallurgy [10, 11] is on the contrary excellently heat conductive, which predisposes it to be used for light-weight design of supporting structure of very energy efficient indoor as well as outdoor thermo-active heat exchangers for building industry of the future. This contribution points to the possibility to apply aluminium foam for both the novel innovative roofing system to cover pitched roofs and the interior ceiling panels, with the minimum energy demands for maintaining the sufficient thermal comfort in future nearly Zero-Energy Buildings (nZEBs).

Abstract: This study deals with high-density polyethylene (HDPE) which was put to the drop weight and tensile impact tests. HDPE is a semicrystalline thermoplastic polymer which is used in common applications such as packaging, consumer goods and car tanks. The injection moulded HDPE samples were subjected the drop weight impact test at different potential energies and the results were subsequently evaluated and discussed. The second test was performed on pendulum test machine where impact resistance in tensile was studied. It was found out that HDPE is a low-cost material with high-performance properties in the field of the impact resistance which was evaluated in penetration and tensile test where the plastic deformation creates.

Abstract: This paper studies different modelling methodologies for a calculation of the three point bend test. Test samples are composed of a rubber matrix and either steel or textile cords reinforcement. Prior to the bending tests, all of the used materials including the matrix and the reinforcement were measured to find out their mechanical properties. Rubber materials were described using hyperelastic models. FEM software MSC Marc/Mentat is employed as a calculation tool and its various functionalities are utilized for a description of the test composite models. The main observed outcome is a dependence of the vertical force causing the test sample deformation on the amount of the deformation. Calculated results are compared to each other and to measurements. Then, all the modelling techniques are evaluated.

Abstract: This paper is devoted to the derivation of material indices using the finite element method. Material indices take into account material properties such a Young’s modulus and density are a powerful tool for material selection for various applications since they allow a quick comparison of suitability of different materials. Until now material indices were developed analytically for rather simple textbook-like examples. However, by implementing the finite element method and data fitting tools material indices can be developed for more complicated problems where the analytical solution cannot be obtained. The current paper describes derivation of material indices using ANSYS software. It is used as a simulator of a physical phenomenon. The simulation generates output data which is used to derive the material index.

Abstract: Patients and surgeons with tibia fracture using external fixator are worried about a higher weight of metal fixator´s construction and therefore also poor manipulation ability with this tool [1]. During the last few years the bone tissue engineering has improved significantly and along with that also material development has increased [2,3]. Therefore patients requirements can be achieved by optimizing the material composition of this product. The main objective of this research is a weight reduction by material and design changes of the external fixator. Another aim is the evaluation of the final model. The model of innovative fixator was created and also computed in software CATIA V5-6 using finite element method simulation. Appropriate forces were applied and the simulation was performed. Results of FEM simulation indicate that the final weight of complete product declined significantly after application of carbon-fiber composite. Test results also suggest that the rigidity and the stability of complete fixator are safe. Hence this research describes that application of carbon fiber composite into the external fixator design is an important improvement of the external fixator.

Abstract: The most frequent research methods applied in various areas of scientific research are computer modelling and numerical simulation. The trend of using finite element method (FEM) gradually replaces classical methods of exploring phenomena. The method is suitable for investigating technical phenomena in the field of construction, mechanics and strength, as well as in other disciplines. Its suitability for the area of ​​strength will be demonstrated in the current paper which presents solutions to various embeddings of a beam under bend. The beam was loaded with an external uniformly distributed load q(x) along its entire length. The research aim was to determine the maximum load and maximum deflection of the beam depending on the beam position and the material used. The beam under bend was selected as the most commonly used structural element. Analytical solution to bending moment and displacement forces is suitable for simple beam loads. Modelling and numerical simulations provide solution to complex problems and different load variations, while identifying changes in material properties of the structural element under consideration. The results are then evaluated and judged on the basis of the maximum strength of the structural material, while meeting the safety condition of the maximum load or maximum deflection. Modelling via FEM is a flexible research method applicable in all research areas.

Abstract: The risk of error in using only uniaxial data for fitting constitutive model curves is emphasized by many hyperelastic material researchers over the years. Unfortunately, despite these indications, often the method is utilized in finding material constants for mathematical models. The reason behind this erroneous practice is the difficulty in obtaining biaxial data. Therefore, as a remedial measure, in this research work we suggest a method of forecasting biaxial data from uniaxial data with a reasonable accuracy. Initially, a set of data is collected through standard uniaxial test. A predefined generalized function is then used to generate a set of values which subsequently used as multiplication factors in order to get biaxial tension data. Eventually, with availability of two data sets, Mooney-Rivlin two parameter model was used for combined data fitting. Material constants were then obtained through least squares approach and thereby theoretical load curves namely uniaxial, equi-biaxial tension and pure shear were drawn. The results of this work suggest a definite improvement related to three curves when compared with only uniaxial test data fitted outcomes. For validation of secondary biaxial data, separate eqi-biaxial test was done and resulting curves were compared. Biaxial primary data curve and forecasted data driven curve show identical data distribution pattern though there is a shift and therefore provide a basis for further research in this direction.

Abstract: The complexity of today's plastic parts as well as the costs, quality makes it necessary to recognize potential errors early, already in the development phase of parts and moulds. Therefore, computer analysis became requisite part of any preprocessing phases. Due to the continuous effort decrease product weight and price many new techniques were developed recently. One relatively new end very effective technique is production of light construction products with using foaming agents. The main aim of this paper is therefore focuses on verification of computer analysis of Microcellular injection moulding process using physical blowing agents for the most used group of polymers which are polyolefins.

Abstract: Industry 4.0 and Logistics 4.0 are highly modern terms. They are connected with the common trend of digitalization, virtualization and networking of data and information. Typical is the implementation of new information and communication technologies into production and logistics practice. This will change the working conditions, processes as well as business models. “Industry 4.0” is the synonym for the 4-th industrial revolution in a general understanding. The term “Industry 4.0” was first used in a high-tech-strategy project of the German government in 2011 at the Hannover Fair. (Compare [1,2]) The paper describes the terms Industry 4.0 and Logistics 4.0 as two of the most important trends in production and logistics. It characterizes the big chances of this development. The paper gives an overview about important solutions in this area. (Compare [3]) Some new solutions are discussed according to material sciences, as it is also very important to develop and use new materials, which help to create smart solutions. Smart materials are created in the areas of e.g. laminated, composite and functionally graded materials, thermal and piezoelectric actuation, active and passive damping, vibrations and waves in smart structures. (Compare [4]) Smart materials allow the design and implementation of actuator, sensor fields and networks. Further examples are self-reporting materials, which autonomously report about problems and defects. This allows an evaluation and control of defects of components during their use and application. (Compare [5])

Abstract: Mechanical behavior of a rubber bushing of a stabilizer of a passenger car is studied in this article. An analysis of behavior of the bushing loaded in the axial direction is performed. An identification of the critical points in the bushing body and, especially, in the interface between the bushing and the stabilizer bar for later optimization of the whole system of the stabilizer fixing in the car construction is the aim of this work. An advanced FEM system including such effects as a strongly nonlinear strain/stress relation of material of the bushing (hyperelasticity), large displacements, large deformations, and contact between the bushing and the stabilizer bar was used for the numerical analysis.