scholarly journals Investigations of the through-thickness residual stress distribution during the partial heating roll forming process of square and rectangular hollow steel sections

2021 ◽  
Author(s):  
Zelalem Abathun Mehari ◽  
Jingtao Han
Keyword(s):  
Residual Stress ◽  
Experimental Studies ◽  
Roll Forming ◽  
Experimental Investigations ◽  
Small Scale ◽  
Stress Distributions ◽  
Forming Process ◽  
Partial Heating ◽  
Steel Sections ◽  
Roll Forming Process

With the growing demand for rectangular and square hollow steel sections in the last few decades, the cold roll forming process has become a widely acknowledged hollow sections manufacturing method; however, residual stress generated during the roll forming process is one of the primary concerns on roll-formed products. In this regard, several researchers have conducted numerical and experimental investigations of residual stress distributions on roll-formed steel sections. However, most of the studies found in the literature have been confined to the measurement of residual surface stresses. On the other hand, experimental studies conducted on fatigue and load-carrying capacity of hollow structural steels have shown that there is indeed a simple relation between the through-thickness residual stress distributions and mechanical properties of structures. Thus, this paper employed a proper numerical modelling procedure using LS-DYNA’s finite element code to explore through-thickness residual stress distributions generated during the roll forming process of rectangular and square hollow steel sections from different material grades. Moreover, a small-scale parametric study was conducted to explore the effects of the partial heating roll forming method on through-the-thickness residual stress distributions to satisfy the growing demand for residual stress-free roll-formed products.

The influence of residual stress on a roll forming process

2015 ◽  
Vol 101-102 ◽  
pp. 124-136 ◽  
Author(s):  
A. Abvabi ◽  
B. Rolfe ◽  
P.D. Hodgson ◽  
M. Weiss
Keyword(s):  
Residual Stress ◽  
Roll Forming ◽  
Forming Process ◽  
Roll Forming Process

scholarly journals The study of forming a roll of pressed hay and the influence of its density on quality parameters

2020 ◽  
Vol 203 ◽  
pp. 04013
Author(s):  
Vyacheslav Terentyev ◽  
Konstantin Andreev ◽  
Nikolay Anikin ◽  
Nikolay Novikov ◽  
Vladimir Teterin ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Quality Parameters ◽  
Middle Part ◽  
Roll Forming ◽  
Winter Period ◽  
Low Density ◽  
Forming Process ◽  
The Core ◽  
Digestible Protein ◽  
Roll Forming Process

Hay is one of the most valuable types of roughage in the diet of ruminants. During the winter period, animals get about half of the nutrients and digestible protein from hay. Leguminous-cereal hay is rich in protein, minerals, carbohydrates, vitamins. When harvesting hay in rolls, balers with a constant-volume pressure chamber are most often used. The roll forming process consists in continuously winding the flow of plant mass onto the core to a predetermined diameter. The process of roll formation occurs due to the gradual compaction of the roll from the outside, as a result of which rolls with a low density core are formed. Studies have shown that hay compaction from the outside leads to the fact that pressure transfer from the outer layers to the inner layers occurs with some delay (stress relaxation) and the location of stems in this case will have some significant effect on the density of hay inside the roll. Experimental studies have shown that the density of hay inside the roll also varies as for the width of the roll. In the middle part of the roll (in width), the density of hay is 2 to 3 times higher than along its edges, the zone of increased density is 0.7 m, which is 44 % of the width of the roll.

Development of an Inverse Routine to Predict Residual Stresses in the Material Based on a Bending Test

2013 ◽  
Vol 554-557 ◽  
pp. 949-956 ◽  
Author(s):  
Akbar Abvabi ◽  
Bernard Rolfe ◽  
Peter Hodgson ◽  
Matthias Weiss
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Test Data ◽  
Bending Test ◽  
Roll Forming ◽  
Stress Profile ◽  
Forming Process ◽  
Residual Stress Profile ◽  
Difficult Time ◽  
Roll Forming Process

Bending with unloading and reverse bending are the dominant material deformations in roll forming and hence property data derived from bend tests could be more relevant than tensile test data for numerical simulation of the roll forming process. Recent investigations have shown that residual stresses affect the material behaviour close to the yield in a bending test. So, Residual stress introduced during prior steel processing may affect the roll forming process and therefore needs to be included in roll forming simulations to achieve improved model accuracy. Measuring the residual stress profile experimentally is expensive, difficult, time consuming and has limited accuracy. Analytical models are available that allow the determination of residual stress. However, for this detailed information about the pre-processing conditions is required; this information is generally not available for roll forming materials. The main goal of this study is to develop an inverse routine that generates a residual stress profile through the thickness of the material based on pure bend test data.

The Effects of Geometric Variables in Roll Forming a Channel Section

1996 ◽  
Vol 210 (2) ◽  
pp. 127-134 ◽  
Author(s):  
S D Zhu ◽  
S M Panton ◽  
J L Duncan
Keyword(s):  
Longitudinal Strain ◽  
Experimental Studies ◽  
Critical Value ◽  
Roll Forming ◽  
Bend Angle ◽  
Forming Process ◽  
Peak Longitudinal Strain ◽  
Angle Bend ◽  
Geometric Variables ◽  
Roll Forming Process

A model of the roll forming process developed previously by the authors was used to examine the effect of geometric variables such as flange length, thickness, bend angle, bend angle increment and roll diameter on the longitudinal strain developed in the roll forming of channel sections. The peak longitudinal strain was found to increase with flange length and then drop when the flange length reaches a critical value. The peak longitudinal strain was found to increase with thickness. In general, increasing the bend angle increment was found to increase the peak longitudinal strain despite the fact that the deformation length also increases. Increasing the roll diameter was found to decrease the peak longitudinal strain. The results from the study explain several roll forming phenomena observed in previous experimental studies.

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