Este trabalho visou entender e avaliar a resistência mecânica da junção de chapas de aço obtidas pelo processo de União de Chapas por Conformação a Frio (UCCF). Esse processo é conhecido no meio industrial pelo termo em inglês: clinching ou press joining. O formato de união cilíndrico, também conhecido como Round, foi selecionado para unir os corpos de provas. As uniões metálicas ensaiadas foram fabricadas com aço de baixo teor de carbono sem camada superficial de proteção (170MPa de limite de escoamento). O material escolhido é de comum utilização na indústria automotiva. Duas espessuras diferentes foram avaliadas: 0,8mm e 1,2mm. Um completo procedimento foi criado para determinar os parâmetros ideais do processo UCCF baseado nos critérios de falha existentes na literatura e na experiência do fornecedor do equipamento. A união em estudo foi submetida, experimentalmente, a cargas multiaxiais com o auxílio de um dispositivo baseado no ensaio de Arcan para possibilitar uma condição de carga combinada, onde foi possível identificar graficamente o comportamento estrutural do corpo de prova em estados de carregamento que variam de tração (normal à superfície do ponto) até cisalhamento (perpendicular à superfície do ponto). Os valores de resistência mecânica encontrados foram de 1,13kN (mínimo) a 2,55kN (máximo) para as chapas de aço com espessura de 0,8mm e de 1,89kN (mínimo) e 3,18kN (máximo) para as chapas de 1,2mm. Um estudo comparativo com Solda Ponto por Resistência Elétrica (SPRE) foi realizado. A UCCF alcançou resultados de 47,68% dos valores obtidos para a SPRE para chapa com espessura de 0,8mm e 37,78% para chapas de 1,2mm. / The purposes of this work were understand and evaluate cold forming sheet metal joining of steel plates mechanical resistance. This process is well known as clinching or press joining. Round clinching element was selected to be used on all tested specimens due to its industry suitability. The metallic specimens were built on mid carbon steel without zinc coat protection (Yield Stress: 170MPa). This is a common material on automotive industry. Two different thicknesses were evaluated: 0.8mm and 1.2mm. A full procedure to determine ideal clinching parameters was created based on available literature information and clinching supplier know-how. All union technology was experimentally submitted to multiaxial loads using device based on Arcan concept. Joining mechanical behavior curves were plotted from traction (normal to element joint surface) to shear (perpendicular to element joint surface) loads. As a result, 0.8mm thickness steel plates achieved load values from 1.13kN (minimum) to 2.55kN (maximum), 1.2mm thickness steel plates achieved values from 1.89kN (minimum) e 3.18kN (maximum). A comparative study was made with Electric Resistance Spot Weld (ERSP). Clinching joining achieved results as 47.68% and 37.78% of ERSP loads for 0.8mm and 1.2mm thickness steel plates respectively.

Este trabalho visou entender e avaliar a resistência mecânica da junção de chapas de aço obtidas pelo processo de União de Chapas por Conformação a Frio (UCCF). Esse processo é conhecido no meio industrial pelo termo em inglês: clinching ou press joining. O formato de união cilíndrico, também conhecido como Round, foi selecionado para unir os corpos de provas. As uniões metálicas ensaiadas foram fabricadas com aço de baixo teor de carbono sem camada superficial de proteção (170MPa de limite de escoamento). O material escolhido é de comum utilização na indústria automotiva. Duas espessuras diferentes foram avaliadas: 0,8mm e 1,2mm. Um completo procedimento foi criado para determinar os parâmetros ideais do processo UCCF baseado nos critérios de falha existentes na literatura e na experiência do fornecedor do equipamento. A união em estudo foi submetida, experimentalmente, a cargas multiaxiais com o auxílio de um dispositivo baseado no ensaio de Arcan para possibilitar uma condição de carga combinada, onde foi possível identificar graficamente o comportamento estrutural do corpo de prova em estados de carregamento que variam de tração (normal à superfície do ponto) até cisalhamento (perpendicular à superfície do ponto). Os valores de resistência mecânica encontrados foram de 1,13kN (mínimo) a 2,55kN (máximo) para as chapas de aço com espessura de 0,8mm e de 1,89kN (mínimo) e 3,18kN (máximo) para as chapas de 1,2mm. Um estudo comparativo com Solda Ponto por Resistência Elétrica (SPRE) foi realizado. A UCCF alcançou resultados de 47,68% dos valores obtidos para a SPRE para chapa com espessura de 0,8mm e 37,78% para chapas de 1,2mm. / The purposes of this work were understand and evaluate cold forming sheet metal joining of steel plates mechanical resistance. This process is well known as clinching or press joining. Round clinching element was selected to be used on all tested specimens due to its industry suitability. The metallic specimens were built on mid carbon steel without zinc coat protection (Yield Stress: 170MPa). This is a common material on automotive industry. Two different thicknesses were evaluated: 0.8mm and 1.2mm. A full procedure to determine ideal clinching parameters was created based on available literature information and clinching supplier know-how. All union technology was experimentally submitted to multiaxial loads using device based on Arcan concept. Joining mechanical behavior curves were plotted from traction (normal to element joint surface) to shear (perpendicular to element joint surface) loads. As a result, 0.8mm thickness steel plates achieved load values from 1.13kN (minimum) to 2.55kN (maximum), 1.2mm thickness steel plates achieved values from 1.89kN (minimum) e 3.18kN (maximum). A comparative study was made with Electric Resistance Spot Weld (ERSP). Clinching joining achieved results as 47.68% and 37.78% of ERSP loads for 0.8mm and 1.2mm thickness steel plates respectively.

Die Entwicklung des heutigen Karosseriebaus schreitet ständig voran. Widerstandspunktgeschweißte Stahlkarosserien stellen gegenwärtig noch immer den Standard in der Automobilindustrie dar. Die Weiterentwicklung zu hochfesten Stahlsorten ermöglicht eine erste Gewichtsreduzierung. Als das immer mehr an Bedeutung gewinnende Aluminium in diesem Bereich vordrang, blieb es nicht aus, sich mit neuen Materialpaarungen wie Aluminium-Aluminium (Al-Al) und im Mischbau Aluminium-Stahl (Al-St) auseinanderzusetzen. Durch die gestiegene Anforderung im Crashtest müssen auch diese neuen Karosserien immer höhere Festigkeitskennwerte und ein besseres Energieaufnahmevermögen erreichen. Für das Fügen der neuen Werkstoffkombinationen aus Al-Al, Al-St bzw. Aluminium mit hochfestem Stahl, soll die Prozessstabilität des in Zukunft immer mehr an Bedeutung gewinnenden Nietclinchens, aufgezeigt werden. Diese Dissertation soll die Vorteile des Verfahrens Nietclinchen gegenüber herkömmlichen Fügeverfahren aufzeigen. Neue Version des Dokuments ergaenzt um Zusammenfassung und Anhang. / The development of the body in white constantly steps forward. Steel bodys joined by spot welding still are standard in the automobile industry. The advancement in the sector of high performance steel makes a reduction in weight possible. When aluminium was getting more important in this sector, it was necessary to think at new material matchings like aluminium-aluminium (Al-Al) and aluminium-steel (AL-St) in the mix construction. Because of rising requirements at crash tests, the bodys have to reach higher data for stability and energy absorption. For the joining process of new material combinations of Al-Al, Al-St and aluminium with high performance steel the operation rivet-clinching will become more important in the future. This dissertation takes a look at the process stability of the rivet-clinching and the advantages in comparison with other joining methods. New version of the document with summary and annex.

The main goal of the diploma thesis is a proposal of alternative metal sheets joining technology which would replace the current technology of spot welding. Different variants have been proposed, and the one which suits the most, the technology of clinching, was compared to the existing one. The costs have been calculated and following results have been concluded: the return of investment of clinching press is about 2 years. In the case of handheld tongs it is 1 and a quarter of a year. Annual savings of clinching press are 234 485 Kč, and in the case of handheld tongs are 258 019 Kč.

Yes / The performance of the modified friction stir clinched and friction stir spot welded joints of AA5754-O and AA2024-T3 Al alloy was improved by investigating the impact of material flow influencing parameters such as material positioning and tool rotational speed on the microstructure, mechanical and fracture behaviors of the joints. The results reveal that the positioning of a harder material (AA2024-T3) as the upper plate induces higher peak temperatures in the friction stir clinched (500 °C) and friction stir spot welded (475 °C) joints. This positioning favors inter-material mingling, grain coarsening with inherent higher dislocation density and tangles, and improved tensile failure loads in the AA2024-T3/AA5754-O joint than the AA5754-O/AA2024-T3 joint. The formation of partial weld-center defect declines in the AA2024-T3/AA5754-O at low tool rotational speed due to the better local heat build-up and geometric-differential flow effect in comparison with the AA5754-O/AA2024-T3 counterparts. The positioning of harder Al alloy on the top of a soft Al alloy is thus recommended for the improvement of modified friction stir clinched joints.

Weight reduction, increased fuel economy, and increased safety of structures in transportation applications has led to much interest in lightweight higher strength structural aluminum alloys. Suitable joining techniques to create such structures with aluminum sheets are required. Generally, similar and dissimilar sheet metals can be joined by adhesive bonding, welding, and mechanical fastening. Difficulty of welding and long processing times for adhesive bonding make mechanical fastening a process of much interest for joining of high strength aluminum sheets. Among the different mechanical fastening techniques available in manufacturing, clinching is a common method of joining by forming in which a punch and die are used to form a geometrical interlock. However, the process introduces surface steps on both sides of the joined sheets where one side consists of a protrusion and the other a pit. Also, clinch joining, a well-accepted and widely used process for joining ductile sheet metals, is more challenging for high strength lower ductility aluminum sheets such as AA7075. The current work aims at studying clinch-ability of high strength lower ductility AA7075 aluminum sheets of different tempers by conventional as well as a new clinching technique called "die-less" clinching. A new tooling was designed in order to conduct die-less clinches. The results showed that room temperature clinching is possible for the softer tempers namely solution treated and annealed states. However, the peak aged sheets failed to form a successful joint. A novel electrical resistance heating technique (ERH) to provide ductility to the joined sheets was used to obtain die-less clinched joints in AA7075-T6. ERH technique provides a large range of heating temperatures from room temperature to 270°C for a current duration of 3 sec. The AA7075-T6 sheets showed a superior joining by using ERH. The joint showed a metallurgical locking mechanism in addition to the commonly available form locking mechanism. / Thesis / Doctor of Philosophy (PhD) / Clinching is a common method of joining sheet metals by forming. A punch and die are used to form a permanent geometrical interlock. However, the process introduces surface steps on both sides of the joined sheets where one side consists of a protrusion and the other a pit. Clinch joining is a well-accepted and widely used process for joining ductile sheet metals. Joining of high strength lower ductility aluminum sheets such as AA7075 is more challenging. The current work aims at joining AA7075 aluminum sheets of different tempers by clinching using the conventional method as well as a new clinching technique called "die-less" clinching. The study includes a new tooling design in order to conduct die-less clinches. Also, a novel electrical resistance heating technique (ERH) to provide ductility to the joined sheets was used to obtain die-less clinched joints in the peak aged AA7075-T6. ERH technique provides a large range of heating temperatures from room temperature to 270°C for a current duration of 3 sec. The AA7075-T6 sheets showed a superior joining by using ERH.

Im Vertrag wird die numerische Verfahrensentwicklung des Flach-Clinchklebens präsentiert. Schwerpunkte bilden hierbei die Bestimmung der Materialdaten und die anschließende Implementierung in das Simulationsmodell sowie die Modellierung des Prozesses. Es wird auf numerische Besonderheiten, wie die Kontaktabbildung zwischen den Blechen und der Klebstoffschicht sowie auf die Trennung der Klebstoffschicht und die damit verbundene Bildung von Klebstofftaschen, eingegangen. Weiterhin werden verschiedene Ansätze vorgestellt, um die Hinterschnittausbildung zwischen den Blechen zu ermöglichen und hierdurch die Handhabungsfestigkeit der Hybridverbindung zu gewährleisten. Abschließend erfolgen die experimentelle Validierung ausgewählter Verfahrensparameter sowie die Bestimmung der mechanischen Verbindungskennwerte.

Die Entwicklung des heutigen Karosseriebaus schreitet ständig voran. Widerstandspunktgeschweißte Stahlkarosserien stellen gegenwärtig noch immer den Standard in der Automobilindustrie dar. Die Weiterentwicklung zu hochfesten Stahlsorten ermöglicht eine erste Gewichtsreduzierung. Als das immer mehr an Bedeutung gewinnende Aluminium in diesem Bereich vordrang, blieb es nicht aus, sich mit neuen Materialpaarungen wie Aluminium-Aluminium (Al-Al) und im Mischbau Aluminium-Stahl (Al-St) auseinanderzusetzen. Durch die gestiegene Anforderung im Crashtest müssen auch diese neuen Karosserien immer höhere Festigkeitskennwerte und ein besseres Energieaufnahmevermögen erreichen. Für das Fügen der neuen Werkstoffkombinationen aus Al-Al, Al-St bzw. Aluminium mit hochfestem Stahl, soll die Prozessstabilität des in Zukunft immer mehr an Bedeutung gewinnenden Nietclinchens, aufgezeigt werden. Diese Dissertation soll die Vorteile des Verfahrens Nietclinchen gegenüber herkömmlichen Fügeverfahren aufzeigen. Neue Version des Dokuments ergaenzt um Zusammenfassung und Anhang. / The development of the body in white constantly steps forward. Steel bodys joined by spot welding still are standard in the automobile industry. The advancement in the sector of high performance steel makes a reduction in weight possible. When aluminium was getting more important in this sector, it was necessary to think at new material matchings like aluminium-aluminium (Al-Al) and aluminium-steel (AL-St) in the mix construction. Because of rising requirements at crash tests, the bodys have to reach higher data for stability and energy absorption. For the joining process of new material combinations of Al-Al, Al-St and aluminium with high performance steel the operation rivet-clinching will become more important in the future. This dissertation takes a look at the process stability of the rivet-clinching and the advantages in comparison with other joining methods. New version of the document with summary and annex.

Yes / In this study, the modified friction stir clinching process was successfully utilized to weld the AA7075-T6 to AA6061-T6 aluminum alloys. The approach of this study was to appraise the influence of the stirring time (6, 12, and 18 s) on the metallurgical and mechanical behavior of the welded samples. The microstructural study demonstrated that stirring time significantly affected joint properties and material flow, which can be ascribed to the discrepancy in the properties of the Al alloys used in this study. Void, local melting and defect-free joints were produced under the stirring times of 6 s, 18 s, and 12 s respectively. It was found that tensile/shear strength increased significantly from 63.5 MPa to 109 MPa as the stirring time increased from 6 s to 12 s, while a further increase in the stirring time to 18 s significantly decreased the joint's strength to 76.1 MPa. The observed failed samples showed that stirring time did not influence fracture mode.

In der vorliegenden Habilitationsschrift werden im ersten Teil bekannte aber auch ausgewählte neue Verfahren zum Fügen von Metallen mit Kunststoffen vorgestellt und miteinander verglichen. Im zweiten Teil werden verschiedene Berechnungsmöglichkeiten für die Auslegung bzw. die Nachweisführung von mechanisch gefügten Verbindungen vorgestellt. Hierbei handelt es sich ebenfalls um bekannte Konzepte als auch um neue Konzepte aus eigenen Forschungsvorhaben. Anhand der Aufbereitung dieser Konzepte in Algorithmen nach DIN 66001 und der Bereitstellung von Beispielen, welche sich auf die Algorithmen beziehen, sind diese einfach anwendbar und für die studentische Ausbildung gut geeignet.:1 Bekannte und neue Fügeverfahren im Leichtbau 1.1 Einleitung zum ersten Kapitel 1.2 Clinchen 1.3 Ultrasonic Fusion Bonding and Clinching 1.4 Clinching with a lost Ring 1.5 Blindnieten 1.6 Flow Drilling Riveting 1.7 Zusammenfassung 2 Auslegungsmöglichkeiten und Bemessungskonzepte 2.1 Einleitung zum zweiten Kapitel 2.2 Berechnung von Vollnietverbindungen nach DIN EN 1993-1-8 2.3 Berechnung von Blindnietverbindungen nach J. Grandt 2.4 Berechnung von Clinch-, Stanzniet- und Blindnietverbindungen nach der Grenznahtfestigkeit / In the first part of this habilitation thesis, known but also selected new processes for joining metals with plastics presented and compared. In the second part, various calculation options for the design and verification of mechanically joined connections are presented. These are also well-known concepts as well as new concepts from our own research projects. Based on the processing of these concepts in algorithms according to DIN 66001 and the provision of examples that refer to the algorithms, they are easy to use and well suited for student training.:1 Bekannte und neue Fügeverfahren im Leichtbau 1.1 Einleitung zum ersten Kapitel 1.2 Clinchen 1.3 Ultrasonic Fusion Bonding and Clinching 1.4 Clinching with a lost Ring 1.5 Blindnieten 1.6 Flow Drilling Riveting 1.7 Zusammenfassung 2 Auslegungsmöglichkeiten und Bemessungskonzepte 2.1 Einleitung zum zweiten Kapitel 2.2 Berechnung von Vollnietverbindungen nach DIN EN 1993-1-8 2.3 Berechnung von Blindnietverbindungen nach J. Grandt 2.4 Berechnung von Clinch-, Stanzniet- und Blindnietverbindungen nach der Grenznahtfestigkeit