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Title: Numerical Forming Simulations and Optimisation in Advanced Materials

Abstract

With the introduction of new materials as high strength steels, metastable steels and fibre reinforced composites, the need for advanced physically valid constitutive models arises. In finite deformation problems constitutive relations are commonly formulated in terms the Cauchy stress as a function of the elastic Finger tensor and an objective rate of the Cauchy stress as a function of the rate of deformation tensor. For isotropic materials models this is rather straightforward, but for anisotropic material models, including elastic anisotropy as well as plastic anisotropy, this may lead to confusing formulations. It will be shown that it is more convenient to define the constitutive relations in terms of invariant tensors referred to the deformed metric. Experimental results are presented that show new combinations of strain rate and strain path sensitivity. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. A procedure is described to automatically compensate the CAD tool shape numerically to obtain the desired product shape. Forming processes need to be optimized for cost saving and product improvement. Until recently, a trial-and-error process in the factory primarily did this optimization. An optimisation strategy is proposed thatmore » assists an engineer to model an optimization problem that suits his needs, including an efficient algorithm for solving the problem.« less

Authors:
; ; ;  [1]
  1. University of Twente, Faculty of Engineering Technology P.O.Box 217, 7500 AE Enschede (Netherlands)
Publication Date:
OSTI Identifier:
21057391
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 908; Journal Issue: 1; Conference: NUMIFORM '07: 9. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17-21 Jun 2007; Other Information: DOI: 10.1063/1.2740825; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALGORITHMS; ANISOTROPY; COMPOSITE MATERIALS; COMPUTERIZED SIMULATION; DEFORMATION; FIBERS; MATERIALS WORKING; NUMERICAL ANALYSIS; OPTIMIZATION; PLASTICITY; PLATES; REINFORCED MATERIALS; SENSITIVITY; STEELS; STRAIN RATE; STRAINS; STRESSES; TENSORS

Citation Formats

Huetink, J., Boogaard, A. H. van den, Geijselears, H. J. M., and Meinders, T. Numerical Forming Simulations and Optimisation in Advanced Materials. United States: N. p., 2007. Web. doi:10.1063/1.2740825.
Huetink, J., Boogaard, A. H. van den, Geijselears, H. J. M., & Meinders, T. Numerical Forming Simulations and Optimisation in Advanced Materials. United States. doi:10.1063/1.2740825.
Huetink, J., Boogaard, A. H. van den, Geijselears, H. J. M., and Meinders, T. Thu . "Numerical Forming Simulations and Optimisation in Advanced Materials". United States. doi:10.1063/1.2740825.
@article{osti_21057391,
title = {Numerical Forming Simulations and Optimisation in Advanced Materials},
author = {Huetink, J. and Boogaard, A. H. van den and Geijselears, H. J. M. and Meinders, T.},
abstractNote = {With the introduction of new materials as high strength steels, metastable steels and fibre reinforced composites, the need for advanced physically valid constitutive models arises. In finite deformation problems constitutive relations are commonly formulated in terms the Cauchy stress as a function of the elastic Finger tensor and an objective rate of the Cauchy stress as a function of the rate of deformation tensor. For isotropic materials models this is rather straightforward, but for anisotropic material models, including elastic anisotropy as well as plastic anisotropy, this may lead to confusing formulations. It will be shown that it is more convenient to define the constitutive relations in terms of invariant tensors referred to the deformed metric. Experimental results are presented that show new combinations of strain rate and strain path sensitivity. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. A procedure is described to automatically compensate the CAD tool shape numerically to obtain the desired product shape. Forming processes need to be optimized for cost saving and product improvement. Until recently, a trial-and-error process in the factory primarily did this optimization. An optimisation strategy is proposed that assists an engineer to model an optimization problem that suits his needs, including an efficient algorithm for solving the problem.},
doi = {10.1063/1.2740825},
journal = {AIP Conference Proceedings},
number = 1,
volume = 908,
place = {United States},
year = {Thu May 17 00:00:00 EDT 2007},
month = {Thu May 17 00:00:00 EDT 2007}
}
  • With the introduction of new materials as high strength steels, metastable steels and fiber reinforce composites, the need for advanced physically valid constitutive models arises. A biaxial test equipment is developed and applied for the determination of material data as well as for validation of material models. An adaptive through- thickness integration scheme for plate elements is developed, which improves the accuracy of spring back prediction at minimal costs. An optimization strategy is proposed that assists an engineer to model an optimization problem.
  • The current paper refers to one of the new non-conventional forming procedures for sheets metal, namely incremental forming. Problems occurring during calculation of stress, thinning and the forces in the process of incremental sheet metal forming have been analyzed in this paper. The paper presents a comparison study based on the simulation by the finite element method of incremental sheet metal forming and experimental researches referred on the same process.
  • Coupling Finite Element (FEM) simulations to mathematical optimisation techniques provides a high potential to improve industrial metal forming processes. In order to optimise these processes, all kind of optimisation problems need to be mathematically modelled and subsequently solved using an appropriate optimisation algorithm. Although the modelling part greatly determines the final outcome of optimisation, the main focus in most publications until now was on the solving part of mathematical optimisation, i.e. algorithm development. Modelling is generally performed in an arbitrary way.In this paper, we propose an optimisation strategy for metal forming processes using FEM. It consists of three stages: amore » structured methodology for modelling optimisation problems, screening for design variable reduction, and a generally applicable optimisation algorithm. The strategy is applied to solve manufacturing problems for an industrial deep drawing process.« less
  • Robustness, reliability, optimisation and Finite Element simulations are of major importance to improve product quality and reduce costs in the metal forming industry. In this paper, we review several possibilities for combining these techniques and propose a robust optimisation strategy for metal forming processes. The importance of including robustness during optimisation is demonstrated by applying the robust optimisation strategy to an analytical test function: for constrained cases, deterministic optimisation will yield a scrap rate of about 50% whereas the robust counterpart reduced this to the required 3{sigma} reliability level.
  • Robustness, reliability, optimisation and Finite Element simulations are of major importance to improve product quality and reduce costs in the metal forming industry. In this paper, we propose a robust optimisation strategy for metal forming processes. The importance of including robustness during optimisation is demonstrated by applying the robust optimisation strategy to an analytical test function and an industrial hydroforming process, and comparing it to deterministic optimisation methods. Applying the robust optimisation strategy significantly reduces the scrap rate for both the analytical test function and the hydroforming process.