Extraction of tool reaction forces using LS-DYNA and its use in Autoform sheet metal forming simulation
2019 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE credits
Student thesis
Abstract [en]
In product development there is still potential to decrease lead times with faster and more accurate simulations. The objective of this thesis was to study whether Finite Element (FE) simulations using explicit LS-DYNA to extract reaction forces from sheet metal forming tools during forming, could be used to improve existing FE models in sheet metal forming software AutoForm.To begin with, the solid CAD-model of the stamping dies were meshed with tetrahedral elements in CATIA and imported into LS-DYNA. In combination with sheet mesh and milling surface meshes from AutoForm, an explicit model was realized. Contacts between sheet mesh and milling surface meshes used the so-called sheet forming contact. The resulting reaction forces were extracted and used in a simulation using the AutoForm software. Resulting simulation was compared to a scan of the physical sheet metal after forming.The direct transfer of reaction forces from LS-DYNA to AutoForm did however not result in the same pressure distribution in AutoForm. The AutoForm simulations using results from LS-DYNA were slightly worse than standard AutoForm simulations.Further work is needed to try and perhaps implement an implicit solution after an initial explicit solution.
Abstract [sv]
Inom produktutveckling finns möjligheter att förkorta ledtider genom snabbare och mera korrekta simuleringar. Syftet med detta arbetet var att undersöka huruvida resultat från explicit LS-DYNA kunde användas för att förbättra nuvarande plåtformningssimuleringar i AutoForm.Den solida CAD-modellen av verktyget meshades med tetraediska element i CATIA och importerades till LS-PrePost, tillsammans med fräsytsmeshar och plåtmesh från AutoForm. Kontakter etablerades mellan plåt och fräsytsmeshar med så kallad sheet forming contact. Modellen löstes sedan explicit. Resulterande reaktionskrafter på plåthållare exporterades till AutoForm och implementerades där. Resulterande simulering jämfördes mot en inskannad fysisk plåt efter plåtformning.Direkt implementering av reaktionskrafter på plåthållaren i AutoForm gav resultat som avvek mer mot inskannad plåt än nuvarande simuleringsstrategi. Direkt implementering av reaktionskrafter gav heller inte en tryckfördelning som liknade den som rapporterades av LS-DYNA.Mer arbete krävs för att om möjligt implementera en implicit lösning efter en initial explicit lösning.
Place, publisher, year, edition, pages
2019. , p. 37
Series
Blekinge Tekniska Högskola Forskningsrapport, ISSN 1103-1581
Keywords [en]
Sheet Metal Forming, Stamping Die, blank holder, Structural Analysis, Finite Element Simulation
National Category
Applied Mechanics
Identifiers
URN: urn:nbn:se:bth-17886OAI: oai:DiVA.org:bth-17886DiVA, id: diva2:1314892
External cooperation
Volvo Cars
Subject / course
Degree Project in Master of Science in Engineering 30.0
Educational program
MTACI Master of Science in Mechanical Engineering
Supervisors
Examiners
2019-05-102019-05-102022-05-12Bibliographically approved