Download or read book Fiber Orientation Analysis of Long Glass Fiber Reinforced Polypropylene in Injection Molded Spiral Flow written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Rheology and Prediction of Three dimensional Fiber Orientation State During Injection Molding of Long Glass Fiber Reinforced Polypropylene written by Andreas Reinhardt and published by . This book was released on 2002 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Rheology and Prediction of Three dimensional Fiber Orientation During Injection Molding of Long Glass Fiber Reinforced Polypropylene written by Andreas Reinhardt and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Natural Fiber Orientation in Polymer Composites Produced by Injection Molding Process written by Rajasekaran Karthikeyan and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Short fiber reinforced polymer composites (SFRPC) produced by injection molding process have established a commercial utilization in all sectors due to low cost and lower weight of the components. The polymers are reinforced with natural fibers to improve their performance. The orientation of short natural fibers in the polymer composite influences the mechanical performance. This research thus focused on the prediction of natural fiber orientation using a theoretical model and then studied the mechanical properties of natural fiber reinforced composites. The theoretical model was derived by incorporating the shape factor of natural fibers into the angular velocity of the fluid element in order to predict the orientation during the injection molding process. The ANSYS- FLUENT software was used to find the velocity distribution in the fluid domain, from which the angular velocity of the fluid element and the orientation angle were found numerically. This numerical orientation result was then compared to the experimental data. The orientation angle of rigid particles rotating at a fixed distance from the inlet gate was measured by an experimental method where a transparent cavity was filled through an injection molding process An experimental setup was developed to study the orientation behavior of short natural fibers in the flowing viscous fluid. Two experimental case studies were conducted to validate the orientation angles of natural fibers using the derived equation. The case study was performed in two molds with one of varying section, and another wide area section and the experimental orientation angles were compared with the numerical predictions. The numerical results of the flow front and velocity distribution obtained from simulation software were compared with digitized images of the flow front from the experimental method. The natural fibers have improved the strength and modulus of the composites. The composite specimens were produced for different compositions of sisal fiber using compression-molding process and the mechanical properties of the composites were studied. An increase in tensile strength, tear strength, and improved hardness was observed in sisal fiber composites. The morphological study using X-ray tomography and Scanning electron microscopy (SEM) has shown the defects, and the fiber orientation. Short fiber reinforced polymer composites (SFRPC) produced by injection molding process have established a commercial utilization in all sectors due to low cost and lower weight of the components. The polymers are reinforced with natural fibers to improve their performance. The orientation of short natural fibers in the polymer composite influences the mechanical performance. This research thus focused on the prediction of natural fiber orientation using a theoretical model and then studied the mechanical properties of natural fiber reinforced composites. The theoretical model was derived by incorporating the shape factor of natural fibers into the angular velocity of the fluid element in order to predict the orientation during the injection molding process. The ANSYS- FLUENT software was used to find the velocity distribution in the fluid domain, from which the angular velocity of the fluid element and the orientation angle were found numerically. This numerical orientation result was then compared to the experimental data. The orientation angle of rigid particles rotating at a fixed distance from the inlet gate was measured by an experimental method where a transparent cavity was filled through an injection molding process An experimental setup was developed to study the orientation behavior of short natural fibers in the flowing viscous fluid. Two experimental case studies were conducted to validate the orientation angles of natural fibers using the derived equation. The case study was performed in two molds with one of varying section, and another wide area section and the experimental orientation angles were compared with the numerical predictions. The numerical results of the flow front and velocity distribution obtained from simulation software were compared with digitized images of the flow front from the experimental method. The natural fibers have improved the strength and modulus of the composites. The composite specimens were produced for different compositions of sisal fiber using compression-molding process and the mechanical properties of the composites were studied. An increase in tensile strength, tear strength, and improved hardness was observed in sisal fiber composites. The morphological study using X-ray tomography and Scanning electron microscopy (SEM) has shown the defects, and the fiber orientation.

Download or read book Analysis of fiber attrition and fiber matrix separation during injection molding of long fiber reinforced thermoplastic parts written by Sara Simon and published by . This book was released on 2016 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Die Erhaltung der ursprünglichen Faserlänge bei der Verarbeitung von glasfaserverstärkten Thermoplasten ist von großem Interesse, da die Endfaserlänge die mechanischen Eigenschaften des Fertigteils bestimmt. Faserbruch im Zuge der Verarbeitung ist unvermeidlich und eine große Herausforderung, da er schwierig zu kontrollieren ist und die zugrunde liegende Physik nach wie vor noch nicht vollständig erforscht ist und verstanden wird. Um ein besseres Verständnis zu bekommen wurde die Faserschädigung von langglasfaserverstärktem Polypropylen in einer Couette Strömung untersucht. Die Ergebnisse zeigen, dass das verwendete Couette Rheometer ein geeignetes Gerät ist um die Auswirkungen von unterschiedlichen Prozessbedingungen auf den Faserbruch zu eruieren, zu isolieren und diese des Weiteren auch zu quantifizieren. Es konnte nachgewiesen werden, dass sowohl die Temperatur, als auch die Faserkonzentration, die Schergeschwindigkeit und die Verweilzeit einen großen Einfluss auf die Faserschädigung haben, die sich in einem Faserbruch von bis zu 90 % widerspiegelt. Die Faserbruchstudie wurde erweitert indem die Faserlängenverteilung entlang der Strömungsrichtung von Spritzgussteilen analysiert wurde. Ein weiterer Teil dieser Arbeit beschäftigte sich mit der Untersuchung der Faser-Polymer-Trennung in Spritzgussteilen, da auch dieses Phänomen beträchtlich zu einem heterogenen Eigenschaftsprofil in den Fertigteilen beiträgt. Zur Evaluierung dieser Faser-Matrix Separation wurden Computertomographie Scans angefertigt, die in Folge mit digitale Bildverarbeitung ausgewertet wurden. Die erhaltenen Ergebnisse zeigen eine deutliche Faser Agglomeration in der Kernschicht des Formteils, in welcher eine Erhöhung der Faserkonzentration von bis zu 40 % festgestellt werden konnte. Die experimentellen Daten aus den Couette Rheometer Experimenten wurden in weiterer Folge zur Validierung und Bewertung von verfügbaren Tools zur Vorhersage der Faserschädigung (Faserbruch Simulation) verwendet. Ein spezielles Augenmerk wurde auf das Phelps Kontinuum Modell gelegt, welches implementiert und in weiterer Folge für die Couette Rheometer Versuche angewandt wurde. Des Weiteren wurden die empirischen Modellparameter aus dem Phelps Modell als Eingangsvariablen für eine Moldex3D Simulation verwendet, um den Faserbruch in einem spritzgegossenem Fertigteil zu bestimmen. Das Phelps Modell wurde erfolgreich umgesetzt, jedoch war es mit den erhaltenen Ergebnissen nicht möglich die Materialabhängigkeit der empirischen Modellparameter zu bestätigen. Die Ergebnisse aus den Modex3D Simulationen zeigen, dass die Phelps Modell Parameter nicht verwendet werden können um den Faserbruch in Spritzgusssimulationen vorherzusagen, da die Parameter nicht übertragbar sind - auch nicht zwischen dem gleichen Material. Da Single Particle Modelle in Prozesssimulationen an Beliebtheit gewinnen, wurde ein kürzlich veröffentlichtes Single Particle Modell auf seine Vorhersagekraft für Faserbruch getestet. Es war möglich, das Modell in einem ersten Schritt qualitativ zu validieren. Jedoch sind zusätzliche Simulationen notwendig, um die Gültigkeit des Modells für ein breiteres Spektrum von Daten zu bestätigen.*****Preserving the initial fiber length of glass fiber-reinforced thermoplastics during processing is from major interest since the residual fiber length determines the mechanical properties of the finished part. Fiber length attrition during processing is still an inevitable and substantial challenge, because it is difficult to control and the underlying physics are not completely understood. In order to gain a better understanding in the phenomena of fiber breakage, the fiber degradation of long glass fiber-reinforced polypropylene in a Couette flow was studied. The results of this work show that the Couette rheometer is an important device to isolate and quantify the impact of processing conditions on the fiber breakage for long glass fiber-reinforced thermoplastics. Temperature, residence time, fiber concentration and processing speed all have a major impact on fiber attrition with breakage rates of up to 90 %.The study was expanded to injection molded parts and the fiber length distribution along the flow path was analyzed. An additional study of injection molded parts focused on the phenomena of fiber-matrix separation since it also causes highly heterogeneous properties within the finished part. This analysis was conducted using micro computed-tomography scans and digital image processing. The results clearly show a substantial fiber agglomeration in the core layer of the molded part of up to 40 % increase from the nominal value.Lastly, the experimental data obtained in this work was used to evaluate available predictive tools for fiber breakage simulation. A comprehensive study focused on the Phelps continuum model, which was implemented and applied for the Couette rheometer experiments. Additionally, the empirical model parameters from the Phelps model were used as an input for a Moldex3D simulation to determine the fiber breakage in an injection molded plaque. The Phelps model was successfully implemented. However, the results were not able to prove the material dependency of the empirical model parameters. The results from the Moldex3D simulations display that the Phelps model parameter cannot be used to accurately predict the fiber breakage in injection molding simulations since the model parameters seem to be not transferable even for the same material. As single particle models become more popular in process simulation, a recently published single particle model was tested for its ability to predict fiber breakage. It was possible to validate the single particle model in a first step, but to confirm the model ́s validity for a broader set of data additional simulations are necessary.

Download or read book Fiber Orientation During Injection Molding of Glass fiber reinforced Thermoplastics written by Joseph Paul Greene and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the though that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemi nation. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 37 (thesis year 1992) a total of 12,549 thesis titles from 25 Canadian and 153 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 37 reports theses submitted in 1992, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

Download or read book Maro Polymer Notes written by and published by . This book was released on 1999 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1994 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polypropylene written by Luciano Paulino da Silva and published by Nova Science Publishers. This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polypropylene (PP) is one of the most largely used man-made polymeric materials. This synthetic stereo-regular polymer has a high tensile strength combined with a low cost, which could explain it's wide usage and application. This book covers some important advances in PP research, including its synthesis, characterizations, modifications, and applications. A thorough understanding of propylene polymerization, mainly concerning its physical and chemical features, as crystalline morphology, for instance, is useful to understand how it could influence PP mechanical properties and heat resistance. These characteristics are directly related to PP rheology and consequently the tendencies to form composites or blends. PP hybrid materials amplify the possibilities of obtaining new useful supplies, and also allow recycling or reusing wastes or low cost resources, as ashes, besides increasing its value.

Download or read book Observation of Fiber Orientation in Injection Molded Long Fiber Reinforced Composites written by 楊怡福 and published by . This book was released on 2018 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis and Performance of Fiber Composites written by Bhagwan D. Agarwal and published by Wiley-Interscience. This book was released on 1990-10-08 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Having fully established themselves as workable engineering materials, composite materials are now increasingly commonplace around the world. Serves as both a text and reference guide to the behavior of composite materials in different engineering applications. Revised for this Second Edition, the text includes a general discussion of composites as material, practical aspects of design and performance, and further analysis that will be helpful to those engaged in research on composites. Each chapter closes with references for further reading and a set of problems that will be useful in developing a better understanding of the subject.

Download or read book Characterization of the Process induced Fiber Configuration of Long Glass Fiber reinforced Thermoplastics written by Sebastian Goris and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long fiber-reinforced thermoplastics have favorable mechanical properties, low manufacturing costs and superior lightweight characteristics. However, the configuration of the reinforcing fibers changes significantly throughout the entire production process, reflected in mechanisms such as fiber attrition, fiber alignment, and fiber matrix separation. The complexity of the process-microstructure-property relationship limits the use of this material class in a wider range of lightweight applications. This work presents a contribution to gain a better understanding of the underlying physics of fiber motion during molding and to obtain a theoretical link between processing and the fiber microstructure. As part of this work, novel characterization techniques were developed to overcome the shortcomings of conventional measurement approaches. The measurement concepts comprise methodologies to characterize the fiber orientation, fiber concentration and fiber length by applying sophisticated techniques, which include combining image processing with micro computed-tomography and optical measurement systems. Applying the developed measurement techniques, a range of experimental studies were conducted to investigate the process-induced fiber microstructure. Plate geometries were injection molded at varying nominal fiber concentrations to investigate fiber matrix separation, fiber alignment, and fiber breakage. The experiments revealed substantial variation in the fiber configuration and correlation between the microstructural properties. The substantial fiber matrix separation and fiber breakage found in this work refute the common assumption of uniform fiber concentration and fiber length in molded parts. Additionally, a new experimental setup based on a Couette rheometer was developed to study fiber length reduction under highly controlled conditions, which isolated the impact of processing conditions on fiber attrition. Finally, the generated experimental data are applied to evaluate models predicting the process-microstructure relationship. All models fail to provide acceptable results and the application of these models as truly predictive tools is limited. It was shown that a holistic approach is necessary to capture the process-induced change in fiber configuration, which necessarily includes the interdependencies of the microstructural properties.

Download or read book The Effect of Fibre Orientation and Dispersion on the Mechanical Properties of Natural Fibre Reinforced Polypropylene written by Billy Cheng and published by . This book was released on 2009 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray microtomography was used to characterize the fibre orientation and dispersion in natural fibre reinforced thermoplastics (NFRTs). Results from the characterization study were used in a modified rule of mixture strength equation to predict the tensile strength of various NFRTs. The predictions were found to be in good agreement with the experimental data, which confirms that poor fibre dispersion causes a decrease in strength at high fibre volume fractions.Extrusion and Injection molding are the main methods for NFRT production commercially. Instead of using extrusion, this study used compression molding to produce NFRTs with a fibre structure similar to that of extruded NFRTs. The mechanical properties of compression and injection molded samples were compared. Compression molded NFRTs were found to have higher tensile and impact strength. This finding suggests that injection molding, which is widely used for quality testing industrially, would underestimate the strength of the extruded products.

Download or read book Improved Fiber Orientation Predictions for Injection Molded Composites written by Jin Wang and published by . This book was released on 2007 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Short fibers are commonly utilized to reinforce the polymer matrix for injection molded parts. Fibers suspended in the molten polymer matrix are oriented by the flow during the mold filling process, and acquire a preferential orientation pattern in the final part. The fiber orientation introduces anisotropy to the mechanical and thermal properties of the material, including the elastic modulus, the tensile strength, and the thermal expansion. A final part is stronger and stiffer in the direction along which the most fibers align, while it is weaker and more compliant in the other directions. An accurate prediction of fiber orientation in injection molding is crucial for designing a mold and controlling part properties. The well-established Folgar, Advani, and Tucker model is widely used to predict fiber orientation. However, recent experiments indicate that this theory overestimates the change rate of the fiber orientation tensor, and therefore predicts a similar orientation pattern in injection-molded parts regardless of the flow length, the part thickness, or the mold filling speed. A strain reduction factor (SRF) was introduced by Huynh (2001) to decrease the change rate of orientation tensor. Though it produces an excellent agreement with experimental data, the SRF model is not objective and encounters difficulty in complex flows. Inspired by the idea of reducing the growth rates of the eigenvalues of the orientation tensor by a scalar factor, a new orientation model was built, in which we modified the closure and fiber-fiber interactions terms accordingly. A possible approach to reduce the rotation rates of the eigenvectors was also explored, but no successful model with this feature was found. A finite difference program was developed and used to simulate the filling process for two simple geometries: end-gated strips and center-gated disks. The program is based upon the Hele-Shaw approximation to solve the velocity field, and implements the new orientation model to predict the fiber orientation. The results using the same scalar factor as the SRF model show an excellent agreement with experimental measurements, for both strips and disks, in small thicknesses and at different filling speeds. A special treatment was proposed for thick strips, to account for the radial flow front that is observed in short-shot experiments and is different from the almost flat flow front in thin strips. The finite difference program was also extended to simulate the filling process of injection molds with rotation, compression, and expansion (RCEM). The comparison of the predicted and measured fiber orientation demonstrates again the usefulness of our new orientation model. The new orientation theory was further implemented to model complex flows where the full equations of motion must be solved. The solver of fiber orientation equations was added to FIDAP(TM), a commercial finite element software, through user subroutines. The final program is able to solve for velocity, temperature, pressure, and fiber orientation in any two- or three-dimensional geometry. Flow through the gate of our end-gated strips was simulated, and the fiber orientation was calculated. The orientation results were compared to the measured values at a region just inside the gate, and then were used as inlet conditions for the finite difference program to successfully predict the downstream orientation. Our new orientation model is aphenomenological theory, and the value of the scalar factor to reduce the orientation change rate is determined by matching experimental data. Since the rheology of a fiber suspension is affected by the fiber orientation, a rheological experiment measuring the shear viscosity and the normal stress difference is one approach to determine the phenomenological parameters. The formulations were worked out for the shear stress and the normal stress difference with respect to the fiber orientation in a parallel-disk rotational rheometer, and the model was fit to the measured values in a least square sense by adjusting the model parameters. This provides a convenient and viable route for determining the parameters of the orientation model.

Download or read book The Effects of Glass Fiber Reinforcement on Injection Molded Polypropylene written by Brian J. Tubby and published by . This book was released on 1997 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Dense Suspension Rotary Diffusion Models for Fiber Orientation Predictions During Injection Molding of Short fiber Reinforced Polymeric Composites written by Babatunde O. Agboola and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a need for physics-based mathematical models for the design of industrial short-fiber reinforced composites (SFRC) to predict the fiber orientation within the part. Traditional models for fiber interactions use the isotropic rotary diffusion model of Folgar and Tucker, but there is considerable interest to use the Phelps and Tucker anisotropic rotary diffusion model. Both models predict the flow induced orientation, which directly determines the resulting stiffness of an injection molded part. These two models are investigated in the present work. A number of fourth order orientation tensor closure approximations are investigated for both diffusion models, with the goal being to suggest the more effective and efficient closure approximation for a variety of flow conditions. Differences in the resulting elastic properties predicted from the two rotary diffusion models are observed. These observations raise questions as to which diffusion model should be used commercially for injection molded SFRCs.