In accordance with the requirement of manufacturing dies quickly and economically,a hybrid forming method of stamping dies for automobile panels is proposed.The method combines digital patternless casting and high-pow...In accordance with the requirement of manufacturing dies quickly and economically,a hybrid forming method of stamping dies for automobile panels is proposed.The method combines digital patternless casting and high-power laser cladding.An experimental study is conducted on the hybrid forming process and its trial production and application in the manufacturing of stamping dies for typical panels.Results prove that the laser cladding layer exceeds HRC60(Rockwell hardness)and thus meets the production efficiency requirement of automobile dies.The rate of defects is well controlled.Compared with traditional technology,this technology has remarkable advantages and advancement.展开更多
In this work it is assessed the potential of combining conventional and incremental sheet forming processes in a same sheet of metal.This so-called hybrid forming approach is performed through the manufacture of a pre...In this work it is assessed the potential of combining conventional and incremental sheet forming processes in a same sheet of metal.This so-called hybrid forming approach is performed through the manufacture of a pre-forming by conventional forming,followed by incremental sheet forming.The main objective is analyzing strain evolution.The pre-forming induced in the conventional forming stage will determine the strain paths,directly influencing the strains produced by the incremental process.To conduct the study,in the conventional processes,strains were imposed in three different ways with distinct true strains.At the incremental stage,the pyramid strategy was adopted with different wall slopes.From the experiments,the true strains and the final geometries were analyzed.Numerical simulation was also employed for the sake of comparison and correlation with the measured data.It could be observed that single-stretch pre-strain was directly proportional to the maximum incremental strains achieved,whereas samples subjected to biaxial pre-strain influenced the formability according to the degree of pre-strain applied.Pre-strain driven by the prior deep-drawing operation did not result,in this particular geometry,in increased formability.展开更多
This research undertakes a nuanced examination of the intersections and distinctions between these two diverse musical traditions.Employing a meticulous comparative analysis,the study scrutinizes fundamental musical e...This research undertakes a nuanced examination of the intersections and distinctions between these two diverse musical traditions.Employing a meticulous comparative analysis,the study scrutinizes fundamental musical elements such as scales,modes,and compositional styles,illuminating shared threads and distinctive attributes that characterize Chinese and Western music.Against the backdrop of contemporary global dynamics,the research investigates the ongoing integration of these musical cultures.It explores the impact of globalization and technological advancements,revealing instances of cross-cultural collaboration and the emergence of hybrid musical forms.Augmenting theoretical discussions with concrete case studies,the paper offers illuminating examples of how Chinese and Western musical elements interweave,contributing to the evolving landscape of global music.This research not only advances scholarly understanding but also contributes practical insights for musicians,educators,and enthusiasts navigating the evolving dynamics of cross-cultural musical expression.By elucidating the intricate relationship between Chinese and Western music cultures,the paper underscores the richness borne out of their interaction and the cultural synthesis that defines contemporary musical landscapes.展开更多
The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme stren...The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme strength-toweight and stiffness-to-weight ratio. Besides monolithic materials such as high-strength or light metals, in particular metal–plastic composite sheets are able to provide outstanding mechanical properties. Thus, the adaption of conventional, wellestablished forming methods for the processing of hybrid sheet metals is a current challenge for the sheet metal working industry. In this work, the planning phase for a conventional sheet metal forming process is studied aiming at the forming of metal–plastic composite sheets. The single process steps like material characterization, FE analysis, tool design and development of robust process parameters are studied in detail and adapted to the specific properties of metal–plastic composites. In material characterization, the model of the hybrid laminate needs to represent not only the mechanical properties of the individual combined materials, but also needs to reflect the behaviour of the interface zone between them.Based on experience, there is a strong dependency on temperature as well as strain rate. While monolithic materials show a moderate anisotropic behaviour, loads on laminates in different directions generate different strain states and completely different failure modes. During the FE analysis, thermo-mechanic and thermo-dynamic effects influence the temperature distribution within tool and work pieces and subsequently the forming behaviour. During try out and production phase,those additional influencing factors are limiting the process window even more and therefore need to be considered for the design of a robust forming process. A roadmap for sheet metal forming adjusted to metal–plastic composites is presented in this paper.展开更多
文摘In accordance with the requirement of manufacturing dies quickly and economically,a hybrid forming method of stamping dies for automobile panels is proposed.The method combines digital patternless casting and high-power laser cladding.An experimental study is conducted on the hybrid forming process and its trial production and application in the manufacturing of stamping dies for typical panels.Results prove that the laser cladding layer exceeds HRC60(Rockwell hardness)and thus meets the production efficiency requirement of automobile dies.The rate of defects is well controlled.Compared with traditional technology,this technology has remarkable advantages and advancement.
基金Fabio Lora gratefully acknowledge LdTM/UFRGS,SENAI CIMATEC and IBF/RWTH-Aachen for their support during the development of this workas well as CAPES for financial support in the form of a scholarship+3 种基金Daniel Fritzen acknowledges CNPq 234851/2014-7(Doutorado Sanduíche no Exterior)-SWERicardo J.Alves de Sousa acknowledges grants UID/EMS/00481/2019-FCT and CENTRO-01-0145-FEDER-022083-Centro2020European Regional Development Fund(ERDF)This research was support by CNPq/DAAD 2010-Doutorado no Exterior-GDE Grant Number 290096/2010-3 in the form of a scholarship.
文摘In this work it is assessed the potential of combining conventional and incremental sheet forming processes in a same sheet of metal.This so-called hybrid forming approach is performed through the manufacture of a pre-forming by conventional forming,followed by incremental sheet forming.The main objective is analyzing strain evolution.The pre-forming induced in the conventional forming stage will determine the strain paths,directly influencing the strains produced by the incremental process.To conduct the study,in the conventional processes,strains were imposed in three different ways with distinct true strains.At the incremental stage,the pyramid strategy was adopted with different wall slopes.From the experiments,the true strains and the final geometries were analyzed.Numerical simulation was also employed for the sake of comparison and correlation with the measured data.It could be observed that single-stretch pre-strain was directly proportional to the maximum incremental strains achieved,whereas samples subjected to biaxial pre-strain influenced the formability according to the degree of pre-strain applied.Pre-strain driven by the prior deep-drawing operation did not result,in this particular geometry,in increased formability.
文摘This research undertakes a nuanced examination of the intersections and distinctions between these two diverse musical traditions.Employing a meticulous comparative analysis,the study scrutinizes fundamental musical elements such as scales,modes,and compositional styles,illuminating shared threads and distinctive attributes that characterize Chinese and Western music.Against the backdrop of contemporary global dynamics,the research investigates the ongoing integration of these musical cultures.It explores the impact of globalization and technological advancements,revealing instances of cross-cultural collaboration and the emergence of hybrid musical forms.Augmenting theoretical discussions with concrete case studies,the paper offers illuminating examples of how Chinese and Western musical elements interweave,contributing to the evolving landscape of global music.This research not only advances scholarly understanding but also contributes practical insights for musicians,educators,and enthusiasts navigating the evolving dynamics of cross-cultural musical expression.By elucidating the intricate relationship between Chinese and Western music cultures,the paper underscores the richness borne out of their interaction and the cultural synthesis that defines contemporary musical landscapes.
基金the German Research Foundation (DFG)German Federation of Industrial Research Associations (AiF)the European Research Association for Sheet Metal Working (EFB)
文摘The global trends towards improving fuel efficiency and reducing CO;emissions are the key drivers for lightweight solutions. In sheet metal processing, this can be achieved by the use of materials with a supreme strength-toweight and stiffness-to-weight ratio. Besides monolithic materials such as high-strength or light metals, in particular metal–plastic composite sheets are able to provide outstanding mechanical properties. Thus, the adaption of conventional, wellestablished forming methods for the processing of hybrid sheet metals is a current challenge for the sheet metal working industry. In this work, the planning phase for a conventional sheet metal forming process is studied aiming at the forming of metal–plastic composite sheets. The single process steps like material characterization, FE analysis, tool design and development of robust process parameters are studied in detail and adapted to the specific properties of metal–plastic composites. In material characterization, the model of the hybrid laminate needs to represent not only the mechanical properties of the individual combined materials, but also needs to reflect the behaviour of the interface zone between them.Based on experience, there is a strong dependency on temperature as well as strain rate. While monolithic materials show a moderate anisotropic behaviour, loads on laminates in different directions generate different strain states and completely different failure modes. During the FE analysis, thermo-mechanic and thermo-dynamic effects influence the temperature distribution within tool and work pieces and subsequently the forming behaviour. During try out and production phase,those additional influencing factors are limiting the process window even more and therefore need to be considered for the design of a robust forming process. A roadmap for sheet metal forming adjusted to metal–plastic composites is presented in this paper.