Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 49 4 2018 02 20 Investigation into Detection Criteria for Wrinkling in Tube Hydroforming Investigation into Detection Criteria for Wrinkling in Tube Hydroforming 829 838 759 10.22060/mej.2016.759 FA S. Navabi Nezhad Department of Mechanical Engineering, University of Mashhad, Mashhad, Iran A. Jaamialahmadi Department of Mechanical Engineering, University of Mashhad, Mashhad, Iran 0000-0001-8747-2884 Journal Article 2015 11 27 One of the most common non-traditional forming process, is the tube hydroforming,<br />which is widely used for to form various tubular parts. To produce final product without any failure,<br />tube hydroforming process is strictly dependent on load path, internal pressure-axial feed. Major<br />modes of failure which may be occur in tube hydroforming process are necking, bursting, buckling and<br />wrinkling. Predicting and preventing each of these failures are very important and leads to defects-free<br />products. In this study, geometrical criteria for detecting wrinkling in numerical methods such as finite<br />element analysis are reviewed. This type of identifying the wrinkling can be pointed out such as the first<br />derivative or geometric slope and length to area indices criteria. In this paper, a new geometric method<br />as a center of volume is introduced. In this case, the center of volume of wrinkled part is not equal with<br />the wrinkled-free one. In order to verify, the results of this new criterion were compared with the results<br />of previous measures and experimental tests in published articles. One of the most common non-traditional forming process, is the tube hydroforming,<br />which is widely used for to form various tubular parts. To produce final product without any failure,<br />tube hydroforming process is strictly dependent on load path, internal pressure-axial feed. Major<br />modes of failure which may be occur in tube hydroforming process are necking, bursting, buckling and<br />wrinkling. Predicting and preventing each of these failures are very important and leads to defects-free<br />products. In this study, geometrical criteria for detecting wrinkling in numerical methods such as finite<br />element analysis are reviewed. This type of identifying the wrinkling can be pointed out such as the first<br />derivative or geometric slope and length to area indices criteria. In this paper, a new geometric method<br />as a center of volume is introduced. In this case, the center of volume of wrinkled part is not equal with<br />the wrinkled-free one. In order to verify, the results of this new criterion were compared with the results<br />of previous measures and experimental tests in published articles. https://mej.aut.ac.ir/article_759_fa14d4fe2f19414de3ebd9f63d5c0169.pdf