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Gerhard Hirt

Bio: Gerhard Hirt is an academic researcher from RWTH Aachen University. The author has contributed to research in topics: Forging & Incremental sheet forming. The author has an hindex of 30, co-authored 335 publications receiving 4463 citations. Previous affiliations of Gerhard Hirt include Saarland University & University of Bath.


Papers
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Journal ArticleDOI
TL;DR: Asymmetric Incremental Sheet Forming has the potential to revolutionize sheet metal forming, making it accessible to all levels of manufacturing as discussed by the authors, and has been shown to be a state-of-the-art in sheet metal manufacturing.

973 citations

Journal ArticleDOI
TL;DR: In this article, the authors focus on forming strategies to overcome these process limits, including the processing of tailor rolled blanks, and finite element modelling of the process is presented and discussed with respect to the prediction of the forming limits of ISF.

227 citations

Journal ArticleDOI
TL;DR: A case study with a car fender section shows that the geometric accuracy of the final part can be improved compared to single-stage forming by a combination of multi- stage forming and stress-relief annealing before trimming.
Abstract: Asymmetric incremental sheet forming (AISF) is a manufacturing process for the small batch production of sheet metal parts. In AISF, a sheet metal part is formed by a forming tool that moves under CNC control. AISF currently has two dominant process limits: sheet thinning and a limited geometric accuracy. This paper focuses on the latter limit. It is shown with a pyramidal part that multi-stage forming can yield an increased accuracy compared to single-stage forming. However, due to residual stresses induced during forming, the accuracy of the as-formed part can be lost if the part is trimmed after forming. A case study with a car fender section shows that the geometric accuracy of the final part can be improved compared to single-stage forming by a combination of multi-stage forming and stress-relief annealing before trimming.

156 citations

Journal ArticleDOI
TL;DR: Incremental bulk forming is the oldest known technique in metal working as discussed by the authors, and many developments in this field have dramatically changed our society, including the development of new machinery for incremental bulk forming, advanced methods for process planning, occurrence of failure modes and the properties of finished products.

152 citations

Journal ArticleDOI
TL;DR: In this paper, a new hybrid process, the combination of AISF and stretch forming, is presented that shows the positive impact of this hybrid process on the process limits, including material thinning, geometric accuracy and the process duration.

149 citations


Cited by
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Journal Article
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

Journal Article
TL;DR: In this paper, two major figures in adaptive control provide a wealth of material for researchers, practitioners, and students to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs.
Abstract: This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

1,814 citations

Book ChapterDOI
01 Jan 1976
TL;DR: A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in Solubility with rise in temperature.
Abstract: A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

1,573 citations

Book ChapterDOI
02 Mar 2001

984 citations