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Residual Stresses in Flow Drill Screwdriving of Aluminium Alloy Sheets

Published

Author(s)

Justin L. Milner, Thomas H. Gnaeupel-Herold, Jamie D. Skovron

Abstract

With an increase in fuel economy standards and the need for reducing emissions set for the automotive sector, has increased the demand for lightweight vehicles. It is well known that the single heaviest component of a passenger vehicle is the body structure, thus has the greatest potential for significantly reducing the vehicle mass. Therefore, transitioning from steel-based bodies to ones composed of lightweight materials, such as: aluminum, magnesium and advanced high strength steels are of great interest. However, with the introduction of these new materials comes with a new means of joining, where conventional methods do not work. Therefore, this work examines a novel joining technique, flow drill screwdriving which is a thermo-mechanical process for joining aluminum and dissimilar materials. The focus of this work is to examine the residual stress distribution in a joint, because mechanical behavior and joint quality are greatly affected by the residual stress. Neutron diffraction was used for the determination of the residual stress in two samples processed with low and high fastener force. The high penetration depth of neutron radiation allows for the determination of triaxial residual stress states inside the material without destruction of the sample. It was found that the stress field around the joint location is in tension, which is problematic if external forces are applied near the joint. Therefore, additional stress measurements were conducted under applied load through a lap shear test. Two load levels were applied to determine the effects on stress concentrations around the proximity of the joint.
Volume
MSEC2016
Conference Dates
June 27-July 1, 2016
Conference Location
Blacksburg, VA
Conference Title
ASME 2016 International Manufacturing Science and Engineering Conference

Keywords

Flow Drill Screwing, Joining, Residual Stress, Neutron Diffraction, Aluminum Alloy

Citation

Milner, J. , , T. and , J. (2016), Residual Stresses in Flow Drill Screwdriving of Aluminium Alloy Sheets, ASME 2016 International Manufacturing Science and Engineering Conference, Blacksburg, VA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920320 (Accessed April 18, 2024)
Created June 27, 2016, Updated February 19, 2017