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 ◽  
...  

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.

Author(s):  
S D Zhu ◽  
S M Panton ◽  
J L Duncan

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.


Author(s):  
Zelalem Abathun Mehari ◽  
Jingtao Han

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.


CIRP Annals ◽  
1995 ◽  
Vol 44 (1) ◽  
pp. 239-242 ◽  
Author(s):  
Manabu Kiuchi ◽  
Kenji Abe ◽  
Ryu Onodera

2018 ◽  
Vol 878 ◽  
pp. 296-301
Author(s):  
Dong Won Jung

The roll forming is one of the simplest manufacturing processes for meeting the continued needs of various industries. The roll forming is increasingly used in the automotive industry to form High Strength Steel (HSS) and Advanced High Strength Steel (AHSS) for making structural components. In order to reduce the thinning of the sheet product, traditionally the roll forming has been suggested instead of the stamping process. The increased product performance, higher quality, and the lowest cost with other advantages have made roll forming processes suitable to form any shapes in the sheets. In this numerical study, a Finite Element Method is applied to estimate the stress, strain and the thickness distribution in the metal sheet with quadrilateral shape, ribs formed by the 11 steps roll forming processes using a validated model. The metal sheet of size 1,000 × 662 × 1.6 mm taken from SGHS steel was used to form the quadrilateral shape ribs on it by the roll forming process. The simulation results of the 11 step roll forming show that the stress distribution was almost uniform and the strain distribution was concentrated on the ribs. The maximum thinning strain was observed in the order of 15.5 % in the middle rib region possibly due to the least degree of freedom of the material.


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