Next Article in Journal
Formation of Metallic Glass Coatings by Detonation Spraying of a Fe66Cr10Nb5B19 Powder
Previous Article in Journal
A Modified Constitutive Model for the Description of the Flow Behavior of the Ti-10V-2Fe-3Al Alloy during Hot Plastic Deformation
Open AccessArticle

Effect of Auto-Tuning on Serrated Flow Behavior

Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON M5B 2K3, Canada
Author to whom correspondence should be addressed.
Metals 2019, 9(8), 845;
Received: 22 July 2019 / Revised: 27 July 2019 / Accepted: 27 July 2019 / Published: 31 July 2019
PDF [2695 KB, uploaded 31 July 2019]


The mechanical response of a servo-hydraulic testing system is affected by the stiffness of test specimens. An adaptive controller helps in auto-tuning the system by setting the optimal proportional-integral-derivative values for the subsequent test as the stiffness changes. This paper presents the effect of auto-tuning of various channels on the flow response of several commercial Al and Mg alloys and a mild steel. Strain-controlled monotonic tensile tests were performed at a given strain rate of 1 × 10−4 s−1 after auto-tuning of position, load, and strain channels in different combinations. Serrated flow or Portevin–Le Chatelier effect was observed in the Al alloys after auto-tuning of either position channel only or position and load channels. However, the serrations of Al alloys were shielded after further auto-tuning of strain channel. The stress-strain curves of Mg alloys and mild steel were observed to be basically free of serrations under any combinations of auto-tuning, which confirms that the serrated flow is a property of specific materials rather than a machine system noise. View Full-Text
Keywords: auto-tuning; strain control; Portevin–Le Chatelier effect; serrated flow auto-tuning; strain control; Portevin–Le Chatelier effect; serrated flow

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Mohammed, S.; Chen, D. Effect of Auto-Tuning on Serrated Flow Behavior. Metals 2019, 9, 845.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Metals EISSN 2075-4701 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top