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Auswahl der wissenschaftlichen Literatur zum Thema „Injected parts quality“
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Zeitschriftenartikel zum Thema "Injected parts quality"
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Ovsik, Martin, Lenka Hylova, Martin Reznicek, Vojtech Senkerik und Michal Stanek. „The Influence of Finishing Operations on the Surface Quality of Injected Parts“. Manufacturing Technology 19, Nr. 3 (01.06.2019): 477–81. http://dx.doi.org/10.21062/ujep/315.2019/a/1213-2489/mt/19/3/477.
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Ramesh, T., S. K. Mayurinathan, R. Saravanan und G. Emayavaramban. „Enhancing power quality of ANN controller based PhotoVoltaic source injected DVR“. International Journal of Engineering & Technology 7, Nr. 2.31 (29.05.2018): 155. http://dx.doi.org/10.14419/ijet.v7i2.31.13430.
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The DVR is a series connected FACTS controller used to compensate voltage disturbance in distribution systems. The main purpose of the DVR is to examine the load voltage waveform regularly if any disorder happens, the equilibrium or excess voltage is injected to the load voltage. The most important advantage of the DVR is observance the users all the time on-line with high quality stable voltage maintaining the permanence of production. In this dissertation, a Photovoltaic voltage injected with an ANN control method for DVR that protects a sensitive load, to counter voltage sag under uneven loading conditions (linear, non-linear) is presented. DVR along with other parts of the distribution system are simulated using MATLAB/ SIMULINK.
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Pagano, Claudia, Rossella Surace, Vincenzo Bellantone, Francesco Baldi und Irene Fassi. „Mechanical characterisation and replication quality analysis of micro-injected parts made of carbon nanotube/polyoxymethylene nanocomposites“. Journal of Composite Materials 52, Nr. 5 (02.07.2017): 645–57. http://dx.doi.org/10.1177/0021998317713258.
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The increasing demand for small and cheap parts is boosting the development of reliable micro-system technologies. Fabrication process capabilities should expand to encompass a wider range of materials and geometric forms, which can satisfy the specific requirements of new emerging micro-products, and ensure the compatibility of new materials and processing technologies. Polymeric composites are very promising materials, since they offer new combinations of properties not available in traditional homogeneous materials. Because of their advantageous light weight, high strength, fatigue life, and corrosion resistance, they are forecast to replace conventional materials in several applications. Among the plastic process technologies, injection moulding is one of the key technologies for manufacturing miniaturised components due to its mass production capability and relatively low production cost. Micro-injection moulding allows to transfer micron and even submicron precision features to small products. Since final product properties strongly depend on materials and production processes and parameters, the process conditions of compounding as well as of product manufacturing have to be carefully studied and controlled. This is particularly important for the manufacturing of micro-products, since, at the micro-scale, some phenomena negligible at the macro-scale (as hesitation effect or capillarity forces for examples) can become important. However, only few studies concern the micro-injection of nanocomposites. Therefore, in this paper the micro-injection of two composites made of polyoxymethylene and carbon nanotubes has been studied. First, the electrical properties of the compounds have been measured; the fillers are dispersed in the matrix and form a network that dramatically increases the conductivity of the composites in comparison with the pristine resin. Then the compounds have been injected using a micro-injection machine and the components have been analysed. The mechanical analysis, based on tensile tests and dynamic-mechanical experiments on miniaturised dog-bone specimens, shows a slight reinforcing effect of the filler; however, the ductility is considerably reduced. This is likely due to a scarce adhesion of the carbon nanotubes and the polymer and the presence of some agglomerates. Moreover, as expected, the mould temperature affects the mechanical properties of the specimens, probably due to its effect on the internal structure of the solidified materials. The dimensional analyses carried out on micro-rib specimens show that replication capability is increased by the presence of the filler and using high values of the process parameters. Finally, microscopic analyses have been done in order to verify the dispersion and orientation of the fillers in the compounds. These effects have been observed only when high shear rates are involved.
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Adam, Andrei, Cristian Cosma und Andrei Pop. „Ultrasonic Activated Injection Used on Manufacturing Thin Wall Plastic Parts“. Applied Mechanics and Materials 555 (Juni 2014): 524–29. http://dx.doi.org/10.4028/www.scientific.net/amm.555.524.
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Processing by injection is the technological process by that the thermoplastics material is injected, under pressure, in the cavity of a mould, where it cools down and solidifies. This process is the most common method for obtaining plastic materials. Injection moulding of thermoplastics has emerged as the premier vehicle for delivering high quality, value added commercial products. Continued global competitiveness has increased standards for product capability and quality while requiring reduced product development time and unit cost. Despite advanced design methods and new process technologies, it is becoming apparent that the injection moulding process is neither flexible nor robust. This paper presents a set of experiments that focused on particular processing conditions of injection through narrow section, thin-wall injection and microinjection. In these cases, the ultrasonic activation does not play an important role as single influence factor but could amplify or strengthen the influence of classical setting parameters of the process: mould temperature, injection pressure and temperature
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Češková, Martina, und Petr Lenfeld. „Polymer Based Injection Mould Cavity Inserts: An Influence on Crystallization and Thermo-Mechanical Properties of Injection Moulded Parts“. Materials Science Forum 994 (Mai 2020): 143–51. http://dx.doi.org/10.4028/www.scientific.net/msf.994.143.
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Injection moulding is a major used technology in mass production of high-quality plastic and composite parts. Once the initial costs have been paid the price per produced part is extremely low and part is then created up to million times. On the other hand, the product development process is time-consuming and costly due to preparation time. Therefore, the efficiency and similarity to real production are essential. Injection moulding into polymer injection mould cavity inserts appears to be an appropriate step in the product development process in particular concerning quickly developing additive manufacturing technologies. Though polymers are thermal insulators, therefore, cooling time is longer compared to injection into fully metal moulds. The impact of different cooling conditions is a change in the crystallization of injected material causing different mechanical properties of products. Removable injection mould cavity inserts were made from PET (Polyethylene terephthalate), PEEK (Polyether ether ketone), PSU (Polysulfone) and PTFE (Polytetrafluoroethylene). The main goal was to compare crystallization and thermo‑mechanical properties of injected PP (Polypropylen) parts into polymer cavity inserts to those injected into a steel mould.
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Adam, Andrei, Cristian Cosma, Adrian Ilie Dume und Sorin Jadaneantu. „Integration of CAD CAM Techniques in the Development of an Injection Mould for Automotive Parts“. Solid State Phenomena 216 (August 2014): 322–25. http://dx.doi.org/10.4028/www.scientific.net/ssp.216.322.
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Processing by injection is the technological process by that the thermoplastics material is injected, under pressure, in the cavity of a mould, where it cools down and solidifies. This process is the most common method for obtaining plastic materials. Injection moulding of thermoplastics has emerged as the premier vehicle for delivering high quality, value added commercial products. Continued global competitiveness has increased standards for product capability and quality while requiring reduced product development time and unit cost. Despite advanced design methods and new process technologies, it is becoming apparent that the injection moulding process is neither flexible nor robust. This paper presents a design process using CAD-CAM software applied to an injection mould for manufacturing a plastic component that is used in the automotive industry. The component was analyzed, measured and subjected to simulations that will certify the quality of the final product.
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Dizon, John Ryan Cortez, Arnaldo D. Valino, Lucio R. Souza, Alejandro H. Espera, Qiyi Chen und Rigoberto C. Advincula. „3D Printed Injection Molds Using Various 3D Printing Technologies“. Materials Science Forum 1005 (August 2020): 150–56. http://dx.doi.org/10.4028/www.scientific.net/msf.1005.150.
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This paper explores the possibility of using different 3d printing methods and materials in the production of polymer molds for injection molding applications. A mold producing a cube was designed using a commercial software. Following the standard 3d printing process, injection molds which could produce a cube were printed using different 3d printing materials and 3d printing technologies. The 3d printing technologies used were Stereolithography (SLA), Polyjet and Fused Filament Fabrication (FFF). A bench-top injection molding machine was used to inject polylactic acid (PLA) in these molds. The quality of the injected parts in terms of dimensional accuracy has been investigated. In some cases, the damage mechanism of the polymer molds has also been observed.
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Brânduşan, Liviu. „Research on the Way of Obtaining the Parts of Sintered Powders by Injection Moulding“. Materials Science Forum 672 (Januar 2011): 237–40. http://dx.doi.org/10.4028/www.scientific.net/msf.672.237.
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For obtaining small parts with complex shape, for which a finishing operation cannot be applied easily, injection forming can be used. For a successful applying of this procedure not only the conditions of the injection process deployment must be taken into consideration, but also the conditions of the binder removal. These conditions impose, in a big measure, the feedstock characteristics, especially the ones of the binder used. The characteristics of the binder mixed with powder influence the injection process, the debinding process and the quality of the injected and sintered parts. Regarding that the binders used are formed from many components, it is very important to know the measure that each of them determines the rheological characteristics of the mixture. In the research made, a binder was used formed from polyethylene, paraffin and stearic acid, a binder which is often used to obtain mixtures for injection. It was watched how these components influence the binder characteristics, the injection process deployment and the effect they have on the quality of the debinded parts.
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Fang, Jian Cheng, Wen Ji Xu, Zhi Yu Zhao und L. Wang. „Influence of In-Flight Particle Characteristics on the Forming Quality“. Materials Science Forum 475-479 (Januar 2005): 2823–26. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.2823.
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There are many technical parameters influencing on the coating quality in plasma spray forming which has become an important technology in materials processing. In this study, the relationships between the melting state, in-flight property of particles injected into plasma jet and the forming quality have been investigated. The experimental results show that the temperature field distributions of plasma jet are mainly affected by plasma generator power though CCD imaging and gray-scale processing. The velocity of in-flight particle is directly determined by the flow rate of work gas, and the surface temperature of in-flight particle is obviously affected by assisted gas rate. It is clear that the energy coupling and momentum transferring between plasma and particle have a significant influence on deposition efficiency, porosity, microhardness and microstructure of spray-formed parts, and it also provides a good idea to control the forming quality on-line.
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Sima, Gabriela, Benjamin Daiguebonne, Leonard Marius Ciurezu-Gherghe, Ionela Gabriela Bucşe, Martin Schwarz und Tibor Hajsz. „Injection Behavior of some Biocomposite Feedstocks“. Advanced Engineering Forum 34 (Oktober 2019): 81–87. http://dx.doi.org/10.4028/www.scientific.net/aef.34.81.
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Recent developments in the field of tissue engineering recommend the 3D printing to obtain the complex shape of the final alloplastic grafts (for soft or hard tissues). The medium pressure injection moulding (MEDPIM) technology could be a cost-effective alternative to 3D printing. This paper presents the first studies for the MEDPIM applicability in the case of some alloplastic bone grafts manufacturing. Two biocomposite feedstocks have been researched in order to obtain the injected parts (herein after named green parts). The Ti6Al4V respectively TiH2, both as powder particles, were mixed with hydroxyapatite (HAP) powders in the W 50 EHT measuring mixer. Both powder mixtures contain NaCl as foaming agent as well as some wax-based binders. The MEDPIM process is developed in the laboratory-scale device, designed and manufactured in the frame of the research project BONY. This device replicates, at lab-scale, the MEDPIM process developed by the Goceram MEDPIMOULD equipment, able to work at mass-production scale. The injection moulding tests were performed at the temperature range of 50…110°C, respectively at 30-45 MPa as injection pressure. The green parts quality was evaluated by means of the physical characteristics (dimensional and density measurements) as well as macroscopic evaluation using the stereomicroscope NIKON SMZ 745T. The influence of the biocomposite feedstock type as well as the injection temperature on the green pats quality is studied in this research.
Dissertationen zum Thema "Injected parts quality"
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Khamzin, Yersin. „Technologie vstřikování zkušebních těles z termoplastů“. Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-444217.
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The diploma thesis focuses on the optimization of technological parameters of plastic injection molding and the study of the influence of technological parameters on the quality of molded test specimens’ type 1A. The quality of molded parts for 3 types of polypropylene (PP) with different melt flow rate (Mosten GB 002, Mosten GB 218, Mosten MA 230) and 1 type of polystyrene (PS) (Krasten PS GP 154) was evaluated in terms of dimensional stability and weight. The contribution of software for modeling the plastic injection molding process was evaluated in this work. SOLIDWORKS Plastics software was used to optimize technological parameters. The construction of the bodies, mold and cooling system was constructed, and test bodies were produced on the basis of parameters obtained from the simulation of the injection molding process. Their quality parameters were compared with a 3D model and for each of the studied materials the optimal technological parameters were selected in terms of quality and the degree of influence of individual injection parameters on the quality of moldings was evaluated. The accordance of the results of the theoretical simulation with the real experiment was proved and a computational module independent of the optimized quality parameters, generally suitable for optimizing the quality parameters of the injected parts, was developed.
Buchteile zum Thema "Injected parts quality"
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„FCM-Based Modeling of LMS Users' Quality of Interaction“. In Fuzzy Logic-Based Modeling in Collaborative and Blended Learning, 388–420. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8705-9.ch014.
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Part III is concluded with this chapter that proposes a Fuzzy Cognitive Map (FCM)-based modeling of the Quality of Interaction (QoI) of the Learning Management System (LMS) users within a blended (b)-learning context, namely FCM-QoI model. Two training/testing scenarios were conducted and explored here, i.e., time-dependent and time-independent, using as pre-validated QoI data the ones presented in chapter 13. Moreover, a FCM-Viewer application that facilitates the visualization of the FCM-QoI model structure is also presented. The experimental results show that the proposed FCM-QoI model can provide concepts interconnection and causal dependencies representation of LMS users' interaction behavior. With this chapter, the circle around the basic fuzzy logic topics discussed in Part II, i.e., FIS, ANFIS, IFIS and FCM, injected into the educational context is fulfilled. Based on the models discussed so far, prospective hybrid modeling approaches are envisioned in the final section of the book (Part IV) that follows.
Konferenzberichte zum Thema "Injected parts quality"
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Kolp, D. A., S. R. Gagnon und M. J. Rosenbluth. „Water Treatment and Moisture Separation in Steam-Injected Gas Turbines“. In ASME 1990 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/90-gt-372.
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Steam injection has been employed in gas turbines for over twenty years. Initially the emphasis was on injection for small amounts of power augmentation and NOx reduction in the turbine exhaust gas. More recently it has been used for massive power increases (more than 50% on some gas turbines) and efficiency improvements (more than 20%). Equipment selection, operation and economics are essential ingredients in producing the high-purity steam required in a steam-injected gas turbine cycle. The most common means of producing steam for the steam-injection cycle is by means of a waste heat boiler operating in the turbine exhaust gas stream. Steam generated in this boiler may then be injected into the compressor discharge, combustor or turbine sections of the gas turbine to improve performance. Manufacturers require extremely high purity steam for injection into their gas turbines; less than 30 parts per billion (PPB) of some contaminants is not an unusual requirement. If this steam quality is not obtained, serious damage can occur, particularly in the turbine hot section. To meet these stringent steam quality requirements without excessive amounts of boiler blowdown, it is necessary to provide highly demineralized makeup water to the boiler, i.e. less than 1 PPM TDS (Total Dissolved Solids). Low silica concentrations are particularly important since silica can vaporize at higher boiler pressures, pass through the moisture separators and deposit on turbine components. The selection of equipment required to produce high quality makeup water from various grades of raw water is critical to the successful operation of the steam injection plant. Because the steam cannot be recovered effectively, it is necessary to install a large water treatment system to provide the quantities of makeup required for steam injection. Equally critical to the cycle is the type of drum moisture separation used in achieving manufacturers’ recommended steam quality. Just as the steam injection cycle has a dramatic impact on the economics of a gas turbine power plant, so too do the operation and selection of steam purification equipment influence the overall economics of the steam injection cycle.
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Alimardani, Masoud, Mehrdad Iravani Tabrizipour und Amir Khajepour. „Effects of Process Parameters on Surface Finish in Laser Solid Freeform Fabrication“. In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11612.
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Laser Solid Freeform Fabrication (LSFF) is a flexible rapid prototyping technique in which a laser beam is used to melt and deposit the injected powder in a layer-by-layer fashion to form 3D components. In this paper, the effects of the main process parameters such as laser power and traverse speed on the surface finish of the parts fabricated using the LSFF process are investigated. Since these process parameters and their variations determine the microstructure and other resultant physical qualities of the fabricated parts, they should carefully be selected to increase the surface quality without compromising other quality aspects of the outcomes. For this purpose, along with the experimental analyses, an experimentally verified 3D time-dependent numerical model is employed to comprehensively study the temperature distributions, thermal stress fields, and their variations resulted from different process parameters and consequently different surface finishes. The experimental investigations are conducted through the fabrications of several thin walls of AISI 303L stainless steel using a fiber laser with a maximum power of 1100 W. The numerical and experimental results show under a constant power feed rate by increasing the process speed while optimizing the laser power, the surface finish of the fabricated parts can improve without compromising the melt pool conditions.
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Schroeffer, Andreas, Matthias Trescher, Konstantin Struebig, Yannik Krieger und Tim C. Lueth. „A Rapid Manufacturing Process for Extrusion-Based 3D Printers“. In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10022.
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Abstract The generation of plastic parts in small volume batches has an enormous economic significance. Application fields for parts in small lot sizes are the fabrication of prototypes in the design process or individualized products. The goal thereby often is not only to produce show objects, but functional parts with specific materials, high dimensional accuracy and proper mechanical properties in a short amount of time. The conventional way to produce thermoplastic plastic parts is given by injection molding and extrusion. Characteristics for this technology are the resulting good and homogeneous mechanical component properties, but shape freedom is limited and the process is time consumptive because an individual tool is needed for each product. Depending on the design of the part the geometry of the tool can be complex and an iterative process is necessary to create a suitable mold. On the other hand, the technology of additive manufacturing is a growing market for the quick and cheap production of parts as prototypes, but still the range of materials is limited and anisotropic mechanical component properties are ongoing problems. The combination of both technologies is known as rapid tooling, where the mold is produced in an additive manufacturing process and then used in an injection molding or casting process. This approach combines the benefits of both technologies in term of time and cost efficiency and good component properties. Problems here are the combination of different materials for mold and component and the missing process knowledge and automatization. In this paper an extrusion-based additive manufacturing technology is used to combine additive manufacturing and injection infill generation for thermoplast in one process. The proposed working principle is to generate the outer contour of the part by filament extrusion as mold to ensure high accuracy and good surface quality and fill the mold using an extrusion process of polymer melt without filament generation. Accordingly, the mold becomes part of the component and the same material can be used for the mold and the infill. Since the viscosity of most thermoplastic polymer melts is too high to fill big structures and undercuts, an algorithm is proposed to generate a chamber structure inside the part. Consequently, the fabrication process consists of several iterative cycles of mold generation and injection processes. For this paper polyamide 6 is used to demonstrate the process. Experiments were performed to find the optimal chamber geometry and size to avoid holes and generate a high quality infill. Several component properties such as density, tensile strength and fabrication time are analyzed. In spite of still existing blowholes, a higher component density could be achieved with the proposed process compared to additive manufacturing. However, the tensile strength is still significantly lower. The failures appeared at the weld lines, where warm polymer melt was injected to already colder chambers below. Still manual processes are sources of possible defects as well. The integration of a RFID chip is shown as an additional feature of the process of easy integration of passive electronic elements.
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Haslinger, W., und D. K. Hennecke. „The Ammonia and Diazo Technique With CO2-Calibration for Highly Resolving and Accurate Measurement of Adiabatic Film Cooling Effectiveness With Application to a Row of Holes“. In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-438.
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The ammonia and diazo technique with CO2-calibration for highly resolving measurement of adiabatic film cooling effectiveness distribution has been developed and improved with respect to high accuracy. Both parts of the technique are based on the analogy between heat and mass transfer. In the ammonia and diazo part a mixture of ammonia and air is injected through the film cooling holes. Downstream of the injection a diazo film is mounted on the experimental surface. Depending on the local ammonia concentrations along the wall the diazo film turns blue. In the CO2-calibration part carbon dioxide is used as a tracer gas. Gas samples are sucked off and analyzed, thus giving the adiabatic film cooling effectiveness at certain locations on the surface. Relating the effectiveness values to the color intensities of the diazo film at the corresponding locations a calibration curve is derived. This calibration can be applied to the whole color distribution of the diazo film resulting in a highly resolved distribution of the adiabatic film cooling effectiveness. The scattering of the measured values along the calibration curve directly indicates the quality of the measurement. The ammonia and diazo technique with CO2-calibration has been applied to injection through a row of holes (α = 35°, p/D = 3) in the flat wall of a wind tnnnel for different blowing rates. The results show a very good suitability of this technique, especially, but not only, if the region around the film cooling holes is of special interest.
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Surace, Rossella, Gianluca Trotta, Alessandro Bongiorno, Vincenzo Bellantone, Claudia Pagano und Irene Fassi. „Micro Injection Moulding Process and Product Characterization“. In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48301.
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Due to its high efficiency for the large scale production of polymeric parts, micro injection moulding is one of the key technologies of the new millennium. Although a lot of researches have been conducted to identify the most effective processing conditions for micro injection moulding, the comprehension of the influence of all parameters on the quality, the properties and the reliability of the moulded parts is still an issue. In this context, this study aims to evaluate the effects of the micro injection moulding process conditions on the tensile properties of micro parts, investigating the influence of three main process parameters: the injection speed, the mould temperature and the melt temperature. A full factorial plan has been applied to study the contributions of these parameters and a second study has been performed to understand the synergic interaction between the two temperatures on the tensile strength. Due to its high level of potential crystallinity, a typical semi-crystalline thermoplastic resin was used in the experiments. The results of the analysis showed a great influence of the mould temperature (Tmould) on the ultimate tensile strength and of the melt temperature (Tmelt) on the deformation at the point of breaking; whereas the injection speed was significant on the overall mechanical performance. A new studied factor (Tmelt-Tmould) could affect the resulting molecular structure and consequently the mechanical behaviour, but itself is not sufficient to thoroughly explain the observed behaviour. Moreover, the visual inspection of the deformation mechanism at break shows three distinctive trends demonstrating the great variability of the mechanical properties of micro-injected specimens due to process conditions.
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Keulen, Casey, Bruno Rocha, Afzal Suleman und Mehmet Yildiz. „Design of an Embedded Sensor Network for Manufacturing Process Monitoring, Quality Control Management and Structural Health Assessment of Advanced Composite Structures“. In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38719.
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This paper proposes the use of an embedded network of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. A single sensor network is used at each stage of life of a RTM composite panel: flow monitoring, cure monitoring and health monitoring. A laboratory scale RTM apparatus was designed and built with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors into the mold has also been developed. Both Fiber Bragg Gratings (FBG) and Etched Fiber Sensors (EFS) have been embedded in composite panels using the apparatus. Etched Fiber Sensors have the capability of detecting the presence of resin. The sensors have proven to be capable of detecting the presence of resin at various locations as it is injected into the mold and have the capability of being multiplexed with FBGs thus reducing the number of ingress/egress locations required per sensor. Two FBGs and three EFSs were embedded on a single optical fiber. Tensile test specimens that contain embedded FBG sensors have also been produced with this apparatus. These specimen and embedded sensors have been characterized using a strain gage and a material testing machine. FBG sensors have been embedded into composite panels also in a manner that is conducive to detecting Lamb waves generated with a centrally located PZT. To detect Lamb waves a high speed, high precision sensing technique is required for embedded FBGs, since these guided waves travel through the material at very high velocities, presenting relatively small strain amplitudes. A technique based in a filter consisting of a second FBG was developed. Since this filter is not dependant on moving parts, it does not limit the velocity or frequency at which the tests can be performed. Preliminary tests performed using this filter showed that it is possible to detect Lamb waves with amplitudes smaller than 1 microstrain. A damage detection algorithm has been developed and is applied to this system in an attempt to detect and localize damages (cracks and delaminations) in the composite structure.
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Chen, H. C., Z. Duan, J. Heberlein und E. Pfender. „Influence of Shroud Gas Flow and Swirl Magnitude on Arc Jet Stability and Coating Quality in Plasma Spray“. In ITSC 1996, herausgegeben von C. C. Berndt. ASM International, 1996. http://dx.doi.org/10.31399/asm.cp.itsc1996p0553.
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Abstract The quality of a plasma sprayed coating is influenced by the plasma jet stability; entrainment of cold air through large scale turbulence can lead to variations in particle heating and trajectories resulting in increased unmelt densities, reduced deposition efficiencies, and oxidation of metal particles. The jet instabilities are in part caused by the swirl flow of the plasma gas. With two modifications to an atmospheric pressure plasma spray torch, we have investigated the influence of reduced swirl flow on jet stability, particle trajectories, and coating quality. The modifications are (1) addition of a shroud consisting of a porous ring surrounding the anode nozzle while simultaneously injecting part of the shroud gas inside the nozzle with a swirl component in the direction opposing the plasma gas vortex, and (2) an injector ring with which part of the plasma gas is injected radially and part tangentially producing reduced vortex flow for the same plasma gas flow rate. Jet stability and particle trajectories are determined using a LaserStrobe system combined with image analysis, and coatings have been evaluated by determining porosity and unmelt density. Results indicate that deposition efficiency is most affected by reduced vortex flow, while the shroud addition reduces unmelt density and porosity.
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Tardif, Xavier, Vincent Sobotka, Nicolas Boyard, Philippe Le Bot und Didier Delaunay. „Determination of Pressure in the Mold Cavity of Injected Semi-Crystalline Thermoplastics“. In ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/esda2012-82134.
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Injection molding is the most used process for thermoplastic part manufacturing. This process is commonly divided into four steps: injection, packing, cooling and ejection. During the packing step, an amount of material gets into the mold cavity to compensate for shrinkage of the polymer mainly due to the crystallization. Once the gate is frozen, polymer is subjected to isochoric cooling while the pressure of the polymer is higher than atmospheric pressure. Improving the quality of the injected part requires prediction of the shrinkage, warpage and residual stress and pressure impacts deeply on the morphology and consequently on the shape of the final part. The pressure decrease during the isochoric phase also determines the ejection time. However, description of the behavior of the polymer during packing and isochoric steps needs an accurate model that considers coupling between heat transfer and crystallization and also a good knowledge of the behavior (specific volume and crystallization kinetics) of the polymer under high pressure. Some studies have already underlined the influence of shear rate on the kinetics of crystallization. Here, based on a pressure analysis and an experimental-numerical comparison, we confirm crystallization is strongly coupled to flow history.
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Van Eikema Hommes, Qi D. „Model-Based Method to Translate System Level Customer Need to Part Specification“. In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28569.
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Products are successful because they meet customer needs. However, many customer needs are not expressed in measurable terms. In addition, when such needs are achieved by a complex system made of hardware parts and software, decomposing customer needs to part-level specification is not a trivial task. This paper presents a model-based approach to address such problems. In the case study, the customer need was the noise and vibration level of an unconventional gasoline engine system when running at idle. The hardware component whose performance tolerance needed to be specified was a new type of fuel injectors. These new fuel injectors had higher piece-to-piece performance variations than the conventional fuel injectors. It was unclear whether such variation was acceptable for customer perceived powertrain quality. A virtual powertrain system simulation model was used to analytically evaluate the impact of the fuel injector performance variability. Monte Carlo simulation was carried out to assess the impact of injector variability. The results from the simulation were further refined using engine hardware testing. This study made recommendations for the acceptable level of hardware tolerance, which was different from what the supplier of the injectors had suggested.
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Ferguson, Jeffrey D., James H. Leylek und Frederick A. Buck. „Film Cooling on a Modern HP Turbine Blade: Part III — Axial Shaped Holes“. In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30522.
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A well-tested computational methodology and high-quality data from a companion experimental study are used to analyze the physics of axial-injected, shaped-hole film cooling on the pressure and suction surfaces of a modern high-pressure turbine blade. Realistic engine conditions, including transonic flow, high turbulence levels, and a nominal density ratio of 1.52, are used to examine blowing ratios of 1.0, 1.5, and 2.0 on the suction surface (SS) and 1.5, 3.0, and 4.5 on the pressure surface (PS). SS results show excellent film-cooling performance with the hole shaping, but massive hot crossflow ingestion is found using similar hole shaping on the PS. Primary mechanisms governing the near and far-field cooling effectiveness and crossflow ingestion are identified, including: (1) the nature of the coolant entry into the film hole; (2) location of hole shaping relative to major coolant flow characteristics; and (3) susceptibility of low-momentum fluid to pressure gradients. Changes in blowing ratio, while not introducing new physical mechanisms, significantly alter the extent to which the mechanisms already present affect the flow. These effects are highly non-linear for both SS and PS geometries, highlighting the inadequacy of one-dimensional design practices and the potential usefulness of CFD as a predictive tool.