Papers by Keyword: Measuring

Abstract: Warp knitting is appointed as a manufacturing method for high-performance and high-quality textiles due to its versatility and production speed. To ensure a continuous and error-free manufacturing process under highly dynamic production conditions, a high level of knowledge of the yarn and machine interaction is required. Mechanical stresses from the machine are transferred to the yarn via friction points, as well as during the stitching process from one yarn to another, where the yarn is subjected to high stresses.Therefore, the focus of this research is the investigation of the friction between the yarn and yarn guiding elements and the friction between the yarns themselves during the stitch formation. For this reason, all contact points between yarn and yarn guiding elements as well as between the yarns themselves are examined and classified. A test rig is set up to determine all occurring frictions as a function of various machine parameters.The knowledge gained and the derived analytical expressions between machine settings and occurring friction can thus become the basis for modeling the friction points of the warp knitting machine, which is also presented. Furthermore, based on the findings a design improvement of the machine can be achieved and the friction model can serve as part of a simulation model of the entire warp knitting machine, which will be the focus of further publications.

Abstract: The article considers the possibility of applying the eddy current method of non-destructive testing for measuring the electrical conductivity of new material - thin metal films. Copper films of various thickness obtained by physical vapour deposition were used as the measurement object. The deposition method and the hardware and software complex for measuring the electrical conductivity of the film were briefly described. A calibration curve that makes it possible to restore the values of the electrical conductivity of the material by the signal value of the eddy current probe was presented. The test results of films with different characteristics were given, and the distribution of the electrical conductivity of the films depending on the batch was shown. Based on different values of the electrical conductivity in a batch, the difference in deposition quality of various films was found.

Abstract: Paper is devoted to the automation of processing the results of measurements of mechanical characteristics of plated specimens and the creation of a mathematical model of anisotropy material. Methods of conducting tensile and flexural tests are described. Developed in MATLAB tools for automation of processing results of experiments are proposed. Tools can be used for interpretation of the results of strength tests of isotropic and composite materials. The advantage of the developed tools is batch processing, which allows processing the results of a large series of experiments. The tools system was tested when creating a model of short-reinforced composite material. An example of the use of test results when constructing the Digimat material model and using this model to predict the stress-strain state of anisotropic structures is presented.

Abstract: The article describes application of using liquid crystals in area of contactless scanning. Concrete application is showed in a turning process oriented to controlling and direction. Polarising attributes of liquid crystals is used in integration of exactness and sesitivity of electrostatical scanning principe and stability and simplicity of optical scanning, whole system has a higher resistance to an exterior disturbing actions and resistance to a possible electrostatical discharge. The article describes a consecution and conditions of practical measuring of principe ́s attestation, elaboration and interpretation of measuring answer.

Abstract: In this paper, there are presented theoretical fundamentals of a real-time health monitoring for a pipeline system. The calculation of the total stress is based on measuring of the real loadings in the form of time-varying strains in critical places of a pipeline system in its real operation. Presented unique deployment of the strain sensors allows to decompose the individual components of loading in cross-section including its vector´s characteristics. The presented monitoring system pursuing the dangerous operational states like an overloading, dangerous vibrations and the fatigue damage accumulation. Monitoring system provides the information about real state of the structure in-time and directly to an operator of service.

Abstract: This paper presents research on the influence of CAM strategies for wear and durability of milling tools. We used two machining principles in this process. In the first instance was constant point of contact with the tool and machining surface. The second method was changing point of the cutting edge in the milling process. Material of tool was hard alloy and high speed steel for machining steel 40CrMnMo7 and C45. The shape of cutting tool was a “Ball Nose” end mill. A DMU 85 monoBLOCK 5-axis CNC milling machine was used. The cutting tool wear was measured in Zoller Genius 3, universal measuring machine and digital microscope, Dino lite 2. The results show differences of cutting tool wear depending on the milling strategy and material of tool.

Abstract: A three-dimensional measurement system has been set up. The digital models have been obtained using a webcam and structured light. After this, a software for measuring the digital geometries has been applied. In order to validate the digital models, the workpiece has been measured in a Laboratory of Metrology by means of a Coordinate Measuring Machine. While digital models can be obtained from multiple scan system configurations, not all of them get the same degree of accuracy. After analyzing the results, it can be determined the best condition for obtaining the digital model so that discrepancies between measurements and corresponding digital model of the workpiece are minimized. Also, it has been estimated a value of measurement uncertainty for each of the models studied.

Abstract: Increase in particulate matter air contamination and its negative impact on human health have resulted in efforts to monitor and identify the sources. Particles are produced by photochemical atmospheric reactions and the coagulation of combustion products from automobiles and stationary sources, with lifetimes of several days or more. The occurrence of particulate matters indoors depends on outdoor pollution and its transport indoors as well as on the presence of indoor sources. This paper aims to carry out a measuring of particular matters concentrations in indoor air of selected buildings and in outdoor air in village of Jasov. The mass concentrations of particulate matters for fractions of 0.5, 1.0, 2.5, 5.0, and 10.0 micrometers were measured and evaluated in order to determine the extent of exposure of people.

Abstract: HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

Abstract: The paper presents a stage of the research concerning the development and improvement of a low cost small flexible coordinate measuring machine (CMM) that could be used in the future both in research and industry. Its main advantage could refer to the low cost (only about 30 ÷ 40% of the cost of a CMM in the category on the market, having similar dimensions) in conditions of high performance criteria. This could be possible due to the fact that they were implemented some recycled components in the construction of the robotic drive axes of the machine structure, low cost scanning devices and low cost mechanical systems for fixing and adapting the scanning devices. The research stage presented in the paper is essential for the later stages of research to develop an integrated concept: low-cost, flexibility, precision and efficiency, all criteria referring to a small portable scanning CMM, with possible application in any domain. Specifically, the described research stage refers to evaluate the implementation of some scanning systems, type non-contact low-cost and modern displacement transducers, on the principle of emission of LASER radiation, in terms of scanning accuracy. The reason is that currently these systems are used more and more in the CMMs construction.