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Title: Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy

Abstract

The motivation to reduce overall vehicle weight within the automotive sector drives the substitution of lightweight materials such as aluminium alloys for structural components. Such a substitution requires a significant amount of development to manufacture structurally parts such that the energy absorption characteristics are not sacrificed in the event of crash. The effects of the manufacturing processes on the crash performance of automotive structural components must be better understood to ensure improved crashworthiness. This paper presents results of an experimental and numerical investigation of the crash response and energy absorption properties of impacted hydroformed aluminium alloy tubes. Crash experiments on hydroformed tubes were performed using a deceleration sled test at the General Motors Technical Center. Results from axial crush testing showed that an important parameter that influences the energy absorption characteristics during crash was the thickness reduction caused by circumferential expansion of the tube during hydroforming. It was found that that the energy absorption decreased as the corner radius decreased, which results because of increased thinning. Sensitivity studies of end feeding parameters, such as end feed level and profile, were carried out to evaluate their impact on the energy absorption of the aluminium tubes.

Authors:
;  [1];  [2]; ;  [3]
  1. National Research Council Canada, Aluminium Technology Centre, 501 University Blvd. East, Chicoutimi, Quebec, G7H 8C3 (Canada)
  2. General Motors Technical Centre, 6250 Chicago Road, Warren, MI (United States)
  3. University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1 (Canada)
Publication Date:
OSTI Identifier:
21061758
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 908; Journal Issue: 1; Conference: NUMIFORM 2007: 9. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17-21 Jun 2007; Other Information: DOI: 10.1063/1.2740907; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM; ALUMINIUM ALLOYS; ENERGY ABSORPTION; EXPANSION; MANUFACTURING; MATERIALS WORKING; PERFORMANCE; SENSITIVITY ANALYSIS; TESTING; TUBES

Citation Formats

D'Amours, Guillaume, Rahem, Ahmed, Mayer, Robert, Williams, Bruce, and Worswick, Michael. Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy. United States: N. p., 2007. Web. doi:10.1063/1.2740907.
D'Amours, Guillaume, Rahem, Ahmed, Mayer, Robert, Williams, Bruce, & Worswick, Michael. Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy. United States. doi:10.1063/1.2740907.
D'Amours, Guillaume, Rahem, Ahmed, Mayer, Robert, Williams, Bruce, and Worswick, Michael. Thu . "Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy". United States. doi:10.1063/1.2740907.
@article{osti_21061758,
title = {Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy},
author = {D'Amours, Guillaume and Rahem, Ahmed and Mayer, Robert and Williams, Bruce and Worswick, Michael},
abstractNote = {The motivation to reduce overall vehicle weight within the automotive sector drives the substitution of lightweight materials such as aluminium alloys for structural components. Such a substitution requires a significant amount of development to manufacture structurally parts such that the energy absorption characteristics are not sacrificed in the event of crash. The effects of the manufacturing processes on the crash performance of automotive structural components must be better understood to ensure improved crashworthiness. This paper presents results of an experimental and numerical investigation of the crash response and energy absorption properties of impacted hydroformed aluminium alloy tubes. Crash experiments on hydroformed tubes were performed using a deceleration sled test at the General Motors Technical Center. Results from axial crush testing showed that an important parameter that influences the energy absorption characteristics during crash was the thickness reduction caused by circumferential expansion of the tube during hydroforming. It was found that that the energy absorption decreased as the corner radius decreased, which results because of increased thinning. Sensitivity studies of end feeding parameters, such as end feed level and profile, were carried out to evaluate their impact on the energy absorption of the aluminium tubes.},
doi = {10.1063/1.2740907},
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}
}
  • The automotive industry, with an increasing demand to reduce vehicle weight through the adoption of lightweight materials, requires a search of efficient methods that suit these materials. One attractive concept is to use hydroforming of aluminium tubes. By using FE simulations, the process can be optimized to reduce the risk for failure while maintaining energy absorption and component integrity under crash conditions. It is important to capture the level of residual ductility after forming to allow proper design for crashworthiness. This paper presents numerical and experimental studies that have been carried out for high pressure hydroforming operations to study themore » influence of the tube corner radius, end feeding, material thinning, and work hardening in 76.2 mm diameter, 3 mm wall thickness AA5754 aluminium alloy tube. End feeding was used to increase the formability of the tubes. The influence of the end feed displacement versus tube forming pressure schedule was studied to optimize the forming process operation to reduce thinning. Validation of the numerical simulations was performed by comparison of the predicted strain distributions and thinning, with measured quantities. The effect of element formulation (thin shell versus solid elements) was also considered in the models.« less
  • The controlled brittle failure of thermosetting fiber-reinforced polymer composites can provide a very efficient energy absorption mechanism. Consequently, the use of these materials in crashworthy vehicle designs has been the subject of considerable interest. In this respect, their more widespread application has been limited by the complexity of their collapse behavior. This article reviews the current level of understanding i this field, including the correlations between failure mode and energy absorption, the principal material, geometric, and physical parameters relevant to crashworthy design and methods of predicting the energy absorption capability of polymer composites. Areas which require further investigation are identified.more » This review article contains 70 references.« less
  • Hearings on the Domestic Refinery Development Act of 1979 are continued in this volume. Studies submitted for the record include: identification and analysis of small refiners incentives; incentives for small refiners to utilize pour crude and/or produce higher octane clear-pool gasoline; and refinery flexibility.
  • Micro-hydroforming is a down-scaled metal forming process, based on the expansion of micro-tubes by internal pressurization within a die cavity. The objective of micro-hydroforming is to provide a technology for the economic mass production of complex shaped hollow micro-components. Influence of size effects in metal forming processes increases with scaling down of metal parts. Investigations into the change in formability of micro-tubes due to metal part scaling down constituted an important subject within the conducted fundamental research work. Experimental results are presented, concerning the analysis of the formability of micro-tubes made from stainless steel AISI 304 with an outer diametermore » of 800 {mu}m and a wall thickness of 40 {mu}m. An average ratio of tube wall thickness to grain size of 1.54 of up to 2.56 was analyzed. Miniaturised mechanical standard methods as well as bulge tests with internal hydrostatic pressurization of the tubular specimens were applied to analyze the influence of size-dependent effects. A test device was developed for the bulge experiments which enabled the pressurization of micro-tubes with internal pressures up to 4000 bar. To determine the attainable maximum achievable expansion ratio the tubes were pressurized in the bulge tests with increasing internal pressure until instability due to necking and subsequent bursting occurred. Comparisons with corresponding tests of macro-tubes, made from the here investigated material, showed a change in formability of micro-tubes which was attributed to the scaling down of the hydroforming process. In addition, a restricted applicability of existing theoretical correlations for the determination of the maximum pressure at bursting was observed for down-scaled micro-hydroforming.« less
  • It is shown experimentally that a transverse rf discharge in tubes has a higher plasmachemical activity than a dc discharge, which deteriorates the parameters of rf discharge-pumped CO{sub 2} lasers. The output power and efficiency of a sealed off CO{sub 2} laser were substantially increased by using a distributed gold catalyst facilitating CO{sub 2} regeneration. The output power of 0.77 W cm{sup -1} per unit length of an active medium with efficiency of 18.5% was obtained in an experimental CO{sub 2} laser with tubes with a distributed gold catalyst pumped by a 27.1 MHz rf discharge. (lasers)