Orientador: Janito Vaqueiro Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-06T10:00:16Z (GMT). No. of bitstreams: 1 Cavaguti_Marcelo_M.pdf: 8323924 bytes, checksum: dbbe1ab33c8e68d868a50f1f3b779398 (MD5) Previous issue date: 2005 / Resumo: O processo de perfilação a frio é usado na indústria de fabricação de metal por aproximadamente 100 anos e seu desenvolvimento se deu com a experiência adquirida pelos operadores das perfiladeiras através do método de tentativa e erro, mas com a evolução das máquinas e da informática, surgiu a tecnologia das simulações computacionais que tem sido amplamente desenvolvida, fornecendo modelos capazes de predizer o comportamento do material de trabalho durante sua conformação mecânica e minimizando o tempo antes gasto com o método de tentativa e erro. Neste estudo, o processo de perfilação a frio foi simulado numericamente através do software MSC SuperForm 2002 baseado no método de elementos finitos com o intuito de analisar o comportamento da tensão longitudinal na região da base da chapa simulada buscando compreender os motivos pelos quais os furos pré-estampados na região da base das chapas de metal perfiladas industrialmente estavam apresentando um estreitamento de sua largura devido ao deslocamento transversal que suas arestas laterais sofriam durante a conformação mecânica do material, e com os resultados das simulações analisados, propor uma novo modelo geométrico para o ferramental da perfiladeira real / Abstract: The cold roll-forming process has been applied in the metal industry for about a hundred years and its development is due to the fact that this experience was acquired by the roll-forming operators through the trial-and-error method. Later, with the evolution of the machines and information technology, it was possible to create a new technology for computer simulations, which has been highly developed, so that it could supply models not only able to predict the behaviour of the work material during its metal forming process but also minimizing the length of time initially spent on the trial-and-error method. In this study, the cold roll-forming process was numerically simulated by MSC Superform 2002 software based on a finite element method with the purpose of analyzing the longitudinal stress behaviour in the region of the simulated sheet web, this study aims for a better understanding about the reasons why the pre-notched holes in the industrially ro11-formed metal sheet web were presenting a narrowing in the width due to a tranversal displacement that their lateral edges were suffering during the metal forming process of the material, and also, with the results of the simulations analized, proposes a new geometric model for the tooled real roll forming / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

<p>This thesis deals with fluid dynamic mechanisms related to papermaking, specif- ically: the initial dewatering mechanisms during roll-forming and fibre motion in sedimentation and in shear flow. </p><p>Pressure and wire position measurements have been conducted in a model resembling the forming zone and the measured pressure distributions are shown to have more complex patterns than the simple model p / T/R (where T is the wire tension and R is the roll radius). It is shown that an increase in wire tension has a similar effect as a decrease in flow-rate on the shape of the pressure distribution. In addition, it is shown that the drainage has a stabilizing effect on the dewatering pressure. </p><p>The flow around the forming roll has also been modelled with the assump- tion that the wire is impermeable. A non-linear equation for the position of the wire is derived that clearly shows that the Weber number, We, is an im- portant parameter. The equation is linearized around the trivial solution and has a standing wave solution with a specific wavelength that scales with the We-number. </p><p>Motion of non-Brownian fibre settling in a Newtonian fluid at a small but finite Reynolds number has been studied experimentally. Two different regimes of sedimentation were identified. For dilute suspensions, fibres gener- ally fall without flipping and may travel at velocities larger than that of an isolated particle. In the semi-dilute regime we found the settling process to be dominated by large-scale fluctuations. The velocity fluctuations scale with the suspension volume concentrationφ according toφ1/3, which is similar to the findings for settling spheres. </p><p>The influence of shear on fibre orientation in the near wall region was studied in cellulose acetate fibre suspensions. At low concentration and low aspect ratio fibres were observed to orient perpendicular to the streamwise direction (named rollers) in the near wall region whereas the orientation further into the suspension was unchanged. As the concentration and aspect ratio increased the fraction of rollers decreased. </p><p>Finally, an evaluation of a commercial Ultra Velocity Profiler unit in fibre suspensions are presented. The idea was to determine the velocity and characterise the turbulence from ultra sound echoes from particles in the fluid. However, the spatial and/or temporal resolution of the measurements did not permit turbulence characterisation. These limitations might be possible to overcome and some procedures are proposed and evaluated.</p>

This thesis deals with fluid dynamic mechanisms related to papermaking, specif- ically: the initial dewatering mechanisms during roll-forming and fibre motion in sedimentation and in shear flow. Pressure and wire position measurements have been conducted in a model resembling the forming zone and the measured pressure distributions are shown to have more complex patterns than the simple model p / T/R (where T is the wire tension and R is the roll radius). It is shown that an increase in wire tension has a similar effect as a decrease in flow-rate on the shape of the pressure distribution. In addition, it is shown that the drainage has a stabilizing effect on the dewatering pressure. The flow around the forming roll has also been modelled with the assump- tion that the wire is impermeable. A non-linear equation for the position of the wire is derived that clearly shows that the Weber number, We, is an im- portant parameter. The equation is linearized around the trivial solution and has a standing wave solution with a specific wavelength that scales with the We-number. Motion of non-Brownian fibre settling in a Newtonian fluid at a small but finite Reynolds number has been studied experimentally. Two different regimes of sedimentation were identified. For dilute suspensions, fibres gener- ally fall without flipping and may travel at velocities larger than that of an isolated particle. In the semi-dilute regime we found the settling process to be dominated by large-scale fluctuations. The velocity fluctuations scale with the suspension volume concentrationφ according toφ1/3, which is similar to the findings for settling spheres. The influence of shear on fibre orientation in the near wall region was studied in cellulose acetate fibre suspensions. At low concentration and low aspect ratio fibres were observed to orient perpendicular to the streamwise direction (named rollers) in the near wall region whereas the orientation further into the suspension was unchanged. As the concentration and aspect ratio increased the fraction of rollers decreased. Finally, an evaluation of a commercial Ultra Velocity Profiler unit in fibre suspensions are presented. The idea was to determine the velocity and characterise the turbulence from ultra sound echoes from particles in the fluid. However, the spatial and/or temporal resolution of the measurements did not permit turbulence characterisation. These limitations might be possible to overcome and some procedures are proposed and evaluated. / QC 20101021

The objective of the current study is the development of an optimization methodology for the energy efficiency of the cold roll forming process. Towards that target, a hybrid modeling approach, utilizing analytical and computational models, is proposed and developed. The energy efficiency indicator for the cold roll forming process is defined, as taking into account the cold roll forming process as a system with energy inputs and outputs. An analytical model was proposed and analyzed for the calculation of such energy efficiency indicator. Internal deformation work for longitudinal and bending strains and pulling frictional work were taking into account. Validation of the analytical model with experimental data and a sensitivity analysis for cold roll forming process variables are then presented. Furthermore a computational model for the cold roll forming process was proposed and analyzed. Simulation methods and modeling approach are analyzed for both forming and springback analysis. The computational model sections and variables are analyzed and results for longitudinal strains are validated with experimental data. The aforementioned modeling approaches were integrated within an optimization methodology, which consist of a robust design algorithm and a closed loop checking for quality constraints. A robust design algorithm implementation was proposed utilizing the analytical model, as taking into account the uncertainty of noise factors within computer experiments. Closed loop checking of quality constraints is implemented using computational model and specified process guidelines. The main outcome of this work is the complete method that was proposed and realized through analytical and computational models. The evaluation of the case study revealed the efficiency and practicality of the suggested approach towards energy efficiency optimization of the cold roll forming process. / Το αντικείμενο αυτής της διατριβής είναι η ανάπτυξη μιας μεθοδολογίας βελτιστοποίησης της ενεργειακής αποδοτικότητας της διεργασίας διαμόρφωσης με περιστρεφόμενους κυλίνδρους. Προς αυτόν τον στόχο, μια υβριδική προσέγγιση μοντελοποίησης, χρησιμοποιώντας αναλυτικό και υπολογιστικό μοντέλο, προτείνεται και αναπτύσσεται. Ο δείκτης ενεργειακής αποδοτικότητας για την διεργασία διαμόρφωσης με περιστρεφόμενους κυλίνδρους ορίζεται, λαμβάνοντας υπόψη τη διεργασία ως ένα σύστημα με ενεργειακές εισροές και εκροές. Ένα αναλυτικό μοντέλο προτείνεται και αναλύεται για τον υπολογισμό του δείκτη ενεργειακής αποδοτικότητας. Υπολογίζονται το εσωτερικό έργο παραμόρφωσης για διαμήκεις και κάμψης παραμορφώσεις, και έργο τριβής μέσω έλξης του υλικού. Το αναλυτικό μοντέλο επαληθεύεται με πειραματικές παρατηρήσεις και στην συνέχεια πραγματοποιείται μία ανάλυση ευαισθησίας για της μεταβλητές της διεργασίας διαμόρφωσης με περιστρεφόμενους κυλίνδρους. Επιπροσθέτως, ένα υπολογιστικό μοντέλο για την διεργασία διαμόρφωσης με περιστρεφόμενους κυλίνδρους προτείνεται και αναλύεται. Οι μέθοδοι προσομοίωσης και η προσέγγιση μοντελοποίησης αναλύονται για τις αναλύσεις διαμόρφωσης και επαναφοράς. Τα τμήματα του υπολογιστικού μοντέλου και οι μεταβλητές του αναλύονται καθώς και τα αποτελέσματα για τις διαμήκεις παραμορφώσεις επαληθεύονται με πειραματικά δεδομένα. Οι εν λόγω προσεγγίσεις μοντελοποίησης ενσωματώνονται σε μία μεθοδολογία βελτιστοποίησης, η οποία αποτελείται από έναν αλγόριθμο εύρωστου σχεδιασμού και έναν κλειστό βρόγχο για τον έλεγχο των ποιοτικών περιορισμών. Η υλοποίηση του αλγόριθμου εύρωστου σχεδιασμού προτείνεται με χρήση του αναλυτικού μοντέλου, παίρνοντας υπόψη την αβεβαιότητα των μεταβλητών θορύβου σε πειράματα με Η/Υ. Ο κλειστός βρόγχος για τον έλεγχο των ποιοτικών περιορισμών χρησιμοποιεί το υπολογιστικό μοντέλο και συγκεκριμένες οδηγίες διεργασίας. Το κύριο αποτέλεσμα αυτής της εργασίας είναι η πλήρης μεθοδολογία που προτείνεται και πραγματοποιείται μέσω αναλυτικού και υπολογιστικού μοντέλων. Η αξιολόγηση της εφαρμογής της μεθοδολογίας σε βιομηχανικό προϊόν αποκάλυψε την αποτελεσματικότητα και την πρακτικότητα της προτεινόμενης προσέγγισης για την βελτιστοποίηση της ενεργειακής αποδοτικότητας της διεργασίας διαμόρφωσης με περιστρεφόμενους κυλίνδρους.

Der Forschungsgegenstand der vorliegenden Arbeit ist die kontinuierliche Herstellung eines profilförmigen Bauteils aus dem Bor-Mangan-Stahl 22MnB5 mit lokal bzw. global definierten mechanischen Eigenschaften. Dabei laufen die Formgebung und Wärmebehandlung (WBH) parallel ab. Die Hauptformgebung erfolgt zunächst im Lieferzustand, an die sich die Wärmbehandlung und die finale Formgebung anschließen. Während der WBH wird das ferritische Anfangsgefüge beim Erwärmen in Austenitgefüge und anschließend durch eine rasche Abkühlung größer 30 K/s in Martensitgefüge umgewandelt. Die Induktorform, -frequenz und die -leistung beeinflussen hierbei maßgeblich die Aufheizrate und das Erwärmungsbild. Durch kontinuierliche Formgebung und die gezielte WBH sind Profilbauteile mit Bauteilfestigkeiten bis 1500 MPa effizient herstellbar. Im Anschluss an eine Machbarkeitsstudie werden experimentelle und simulative Untersuchungen durchgeführt und die gewonnenen Ergebnisse miteinander verglichen. Dadurch kann die prinzipielle Eignung des FE-Modells nachgewiesen werden. Im Weiteren erfolgt der Vergleich von drei verschiedenen Fertigungsrouten, wobei das Hauptaugenmerk auf der erforderlichen Umformkraft und der erreichbaren Formgenauigkeit liegt. Auf Basis der Simulationsergebnisse kann festgehalten werden, dass mittels der untersuchten Technologie höchstfeste und formgenaue Profilbauteile mit definierten mechanischen Eigenschaften herstellbar sind. Der Einsatz der Technologie birgt somit ein enormes Leichtbaupotenzial. Dennoch gibt es Hemmnisse die Technologie einzusetzen, da „Wärme“ in den traditionell kalt ablaufenden Umformprozess eingebracht wird. Die Arbeit soll dazu beitragen, diese Barriere abzubauen.:1 EINLEITUNG 2 STAND DER FORSCHUNG UND ENTWICKLUNG 3 HANDLUNGSBEDARF, ZIELSETZUNG UND LÖSUNGSWEG 4 VERSUCHSPLANUNG 5 VERWENDETE WERKSTOFFE SOWIE ANLAGEN- UND WERKZEUGTECHNIK ZUR ENTWICKLUNG EINER TECHNOLOGIE ZUR HERSTELLUNG EINTEILIGER, EIGENSCHAFTSSKALIERTER PROFILBAUTEILE 6 REFERENZVERSUCHE V-GESENKBIEGEN UND KALTWALZPROFILIEREN EINES HUTPROFILS AUS 22MNB5 7 STATIONÄRES AUFHEIZVERHALTEN EINES RINGINDUKTORS UND ABSCHRECKEN MITTELS UNTERSCHIEDLICHER KÜHLMEDIEN 8 INTEGRATION EINER WÄRMEBEHANDLUNG IN DEN KONTINUIERLICHEN WALZPROFILIERPROZESS 9 ZUSAMMENFASSUNG 10 AUSBLICK / The research object of the present work is the continuous production of an open profile component made of the manganese-boron steel 22MnB5 with locally or globally defined mechanical properties. The shaping and heat treatment (SHT) take place in one process. The main shaping is first carried out in the as-delivered condition, followed by heat treatment and final shaping. During the heat treatment, the initial ferritic microstructure is transformed into an austenitic state during heating and then into a martensitic microstructure by rapid cooling at a rate of more than 30 K/s. The geometry of the induction coil, the frequency and the heating power have a significant influence on the heating rate and the heating effect. Through continuous shaping and controlled SHT, profile components with strengths of up to 1500 MPa can be produced efficiently. Following a feasibility study, experimental and simulative investigations were carried out and the results obtained were compared with each other. In this way, the principle suitability of the FE model could be demonstrated. In further steps, three different production routes were com-pared, whereby the main focus was on the required forming force and the achievable forming accuracy. Based on the obtained results, it can be stated that the investigated technology can be used to produce high-strength and dimensionally accurate profile components and defined mechanical properties with high output rate. The use of this technology thus offers a huge lightweight potential. However, as additional heat is introduced into the traditionally cold forming process, the process is more complexity and this constitutes a barrier to the use of the technology. This work is intended to overcome this barrier.:1 EINLEITUNG 2 STAND DER FORSCHUNG UND ENTWICKLUNG 3 HANDLUNGSBEDARF, ZIELSETZUNG UND LÖSUNGSWEG 4 VERSUCHSPLANUNG 5 VERWENDETE WERKSTOFFE SOWIE ANLAGEN- UND WERKZEUGTECHNIK ZUR ENTWICKLUNG EINER TECHNOLOGIE ZUR HERSTELLUNG EINTEILIGER, EIGENSCHAFTSSKALIERTER PROFILBAUTEILE 6 REFERENZVERSUCHE V-GESENKBIEGEN UND KALTWALZPROFILIEREN EINES HUTPROFILS AUS 22MNB5 7 STATIONÄRES AUFHEIZVERHALTEN EINES RINGINDUKTORS UND ABSCHRECKEN MITTELS UNTERSCHIEDLICHER KÜHLMEDIEN 8 INTEGRATION EINER WÄRMEBEHANDLUNG IN DEN KONTINUIERLICHEN WALZPROFILIERPROZESS 9 ZUSAMMENFASSUNG 10 AUSBLICK