Elastic Rolling Research Articles

Surface texture transfer in skin-pass rolling under mixed lubrication

This paper presents a novel integrated approach to modeling surface texture transfer in skin-pass rolling under mixed elasto-plasto-hydrodynamic lubrication (EPHL). The innovation lies in combining discrete fast Fourier transform (DC-FFT) for precise characterisation of elastically deformed asperities on the roll surface, dynamic explicit finite element analysis (FEA) for capturing cross-scale deformations, and a transient average Reynolds equation for governing the lubrication flow. By integrating these methods, the model addresses the complex interplay between elastic roll deformation, microscale asperity-lubricant interactions, and elastoplastic strip deformation, providing a more comprehensive understanding of texture transfer mechanisms. In addition, the model predictions are validated by experimental results. Furthermore, this study investigates the effects of rolling speed and surface pattern orientation, revealing that higher speeds reduce texture transfer while surface patterns aligned with the rolling direction enhance it. These insights demonstrate the potential of this integrated modeling approach for advancing the field of skin-pass rolling.

Current-carrying tribological properties of an elastic roll ring under different currents

A novel rotating conductive joint that comprises an inner raceway, outer raceway, and a roll ring is proposed in this study. The tribological and conductive properties of the rolling rings were studied under current conditions of 0–20 A. The current density of the rolling contact reached 419 A/mm2 when transmitted at 20 A. However, a high current could result in a high-friction coefficient and severe wear. The results of optical microscopy and electron back-scattered diffraction showed that the grain boundary was partially annihilated, and the stress decreased in the wear area under 10 and 20 A. On the wear surface, the current-carrying friction caused the hardening, and the electroplasticity caused softening. The surface hardness of the wear area was the result of competition between hardening and softening, which reached its highest value at 5 A.

Shape optimization of a linearly elastic rolling structure under unilateral contact using Nitsche’s method and cut finite elements

The main motivation of this work is to develop a numerical strategy for the shape optimization of a rolling elastic structure under contact with respect to a uniform rolling criterion. A first objective is to highlight the influence on the treatment of the contact terms. To do so, we present a numerical comparison between a penalty-based approach and the use of Nitsche’s method which is known to have good consistency properties. A second task concerns the construction of an objective functional to force the uniform rolling criterion. Here, we present and compare two different strategies that will lead to quite similar results. All the numerical experiments proposed in this paper were performed using a fictitious domain approach coupled with a level set representation of the shape and the use of a cut finite element method to approximate the elastic equation.

Structures Dynamic Property Analysis of Elastic Composite Cylindrical Rolling Element

Elastic composite cylindrical roller bearing is a novel type of roller bearing whose rolling element is designed by innovating the rolling element structure of cylindrical roller bearings. For the purpose of investigating the dynamic properties of the rolling elements with different structural parameters and solving the modes of elastic composite cylindrical rolling element with different filling degrees, first, this study compares elastic composite cylindrical rolling element to solid cylindrical rolling element, in terms of natural frequency and vibration mode. Next, the integration time step is determined, based on the natural frequency of the vibration in the Y direction, the response of various rolling element, under impact loads, is solved. Furthermore, the laws of the energy changes and nodal displacement variations of rolling element are explored, at different filling degrees. Finally, adopting the decay method, the damping ratio of elastic composite cylindrical rolling element, under different structural parameters and external loads, is calculated. According to the results, with the increase of filling degree, the natural frequencies of various orders of elastic composite cylindrical rolling element gradually declined. The damping ratio of rolling elements decreased, as the filling degree increased, while it could be changed by adjusting the structural dimensions of rolling elements. The analysis results of this study provide some theoretical reference for studies on the parameter optimization of rolling element structures, the vibration and noise reduction of elastic composite cylindrical roller bearings.

New pile foundation structures for swelling clay soils

The information on the basics of designing pile foundations on swelling clay soils is presented and analyzed. New designs of conical piles and those with a variable cross-section, in which the soil mass swelling is accompanied by the effect of pile pinching, have been developed. Moreover, new pile foundation structures with protective shells involving a calcium elastic rolling member and some rubbing elements like low-friction plastic and metal braces are proposed.

Modeling and optimization of the elastic rolling process in order to increase the wear resistance of the surface layer of high-precision thin-walled parts of ship machinery and mechanisms

Ways of improving elastic rolling to ensure the required hardness of the resulting surface layer are considered. Analytical dependences of the hardness of the surface layer of the processed part on the determining factors are given. Keywords: process, elastic rolling, microhardness, parameters, planning, experiment, multifactority, technique. aydin.qafarov@hotmail.com

To the development of the theory of contact interaction in two-roll modules

The results of the study of the stress-strain state in a two-roll module are presented. The angles that determine the characteristic points of the physical model of the roll contact curves are defined for the case when the strain properties of the material layer and elastic roll coatings are given by power dependences. Formulas are derived for calculating the angles of entering and exit, the angles separating the no-slip zones from the lag and advance slip zones, neutral angles and angles of maximum normal stresses of the two-roll module. It was stated that an increase in the friction coefficient of the roll with the material being processed leads to a decrease in the percentage of slip zones in the contact curve in the driven roll. It was revealed that with an increase in the dynamic coefficient, the slip lag zone decreases, and the advance slip zone increases. It was determined that the faster the feeding rate of the material layer, the greater the percentage of the no-slip zone in the roll contact curve. It was revealed that in the driven roll the neutral angle is inclined towards the entrance of the material layer into the contact zone of the rolls.

Influence of Factors Involved in the Elastic Rolling Process on Residual Stresses in the Surface Layer of Equipment Parts

The article presents the results of studies into the influence of various factors involved in a new elastic rolling process on residual stresses in the surface layer of high-precision non-rigid thin-walled parts. Modeling and optimization of the process are carried out to ensure maximum compressive residual stresses in the surface layers of equipment parts.

Using the kinematic radius in the mechanics of elastic wheel rolling

As you know, in the mechanics of a wheel with an elastic tire, both dynamic (rd) and kinematic (rk) radius are widely used. At the same time, specialists in the theory of the motion of wheeled vehicles still do not have a clear understanding of the scope of their application. Keywords: elastic wheel, kinematic radius, circumferential force, dynamic radius, wheel traction force, instantaneous center of speeds, torque, solid, rolling resistance

Effect of the elastic deformation of rolls on the surface texture transfer in skin-pass rolling

This paper investigates the surface texture transfer with elastically deformed work rolls in skin-pass rolling. A numerical approach was developed to efficiently overcome the multiscale challenges associated with the numerical characterisations. To couple the microscale plastic deformation of strip surface asperities with the microscale elastic deformation of roll surface asperities, a specific method was first developed to generate the characteristics between normal contact pressure and interface separation. To deal with the three-dimensional deterministic rough surfaces, a material redistribution scheme was used to predict the plastic deformation of the strip surface asperities and a discrete fast Fourier transform algorithm was employed to efficiently calculate the elastic deflection of the roll surface asperities. These enabled the subsequent multiscale analysis in coupling the microscale interface contact with the macroscale deformation of the metal strip and work roll. As such, the stick/slip transition in the rolling bite due to the elastic deformation of the roll as well as the surface topography of the rolled strip have been quantified. The new method has successfully revealed the effects of elastic roll deformation, roll radius, and strip thickness/roughness on the resultant surface texture of strips in skin-pass rolling.

Analytical determination of application point and normal reaction arm when rolling a wheel on a drum

Evaluation of the rolling resistance of car tires is now often performed on drum stands like car tests. This necessitates the study of the mechanics of interaction between the wheel and the drum in order to determine its force and kinematic characteristics, including the values and points of application of tangential and normal forces in contact with the drum. These problems can be solved taking into account that the mechanics of elastic wheel rolling on a drum is the same as when rolling on a flat rigid support surface. In this paper, from consideration of the mechanics of interaction between an elastic wheel and a drum, using the equations of power balance and force equilibrium of the wheel, the equations for determining the point of normal reaction in contact and its arm relative to the wheel axis during its rolling along one and two drums have been derived.. These dependencies have a simple form and can be applied when considering the rolling of both a single wheel and the car as a whole on a drum stand.

Mathematical modeling of the elastic rolling process and optimization of its parameters to reduce the roughness of the processed surface of high-precision non-rigid thin-walled parts

The possibilities of a new technological process — elastic rolling are considered. Modeling and optimization of the process were performed to ensure the minimum surface roughness of the treated surface. Keywords elastic rolling, surface roughness, parameter, modeling, optimization, part. aydin.qafarov@hotmail.com

Probabilistic optimization of engine mount to enhance vibration characteristics using first-order reliability-based target cascading

Uncertainties cause tremendous failures, especially in large-scale system design, because they are accumulated from each of the subsystems. Analytical target cascading is a multidisciplinary design optimization method that enables the achievement of a concurrent and consistent design for large-scale systems. To address the uncertainties in analytical target cascading efficiently, we propose reliability-based target cascading combined with first-order reliability assessment algorithms, such as mean-value first-order second moment, performance measure analysis, and reliability index analysis. The effectiveness of the implemented algorithms was first demonstrated via a mathematical programming problem and then a practical engineering problem, involving automotive engine mount optimization, for minimizing both the difference between torque roll axis and elastic roll axis and the vibration transmissibility under mode purity requirements. The optimized design solutions are compared among three reliability assessment algorithms of reliability-based target cascading, and the uncertainty propagation with Gaussian distributions was quantified and verified. The probabilistic design results indicate that the first-order reliability-based target cascading methods successfully identify more reliable and conservative optimized solutions than analytical target cascading.

Analysis of elastic rolling stand deformation and interstand tension effects on section faults of hot rolled wire rod and bars

Abstract The present work aims at the modelling and simulation of the hot rolling process for wire rod and bars. After the fundamentals of plasticity, which are essential for the understanding of the process characteristics have been described, typical section deviations that can be expected in wire rod and bar mills are calculated with help of a numerical simulation model. The model allows the calculation of section shapes under the influence of elastic rolling stand deformations and interstand tensions. From this computational assessment of section faults, the necessity of inline measurement and process control for wire rod and bar mills is shown. This work is part of the PIREF project which incorporates the development of sensors, control systems and process models in order to control the dimensional accuracy of hot rolled wire rod and bars. The metal forming process model, as described here is used internally as a model for the static and kinematic interactions in the rolling process inside of the control model.

Multi-objective genetic algorithm in reliability-based design optimization with sequential statistical modeling: an application to design of engine mounting

The present study explores reliability-based design optimization (RBDO) using multi-objective genetic algorithm (MOGA) in the context of practical engineering design. The reliability analysis is carried out using a most probable point-based method with first-order sensitivities. As an effective optimization approach, the two methods MOGA and RBDO are integrated to propose a multi-objective reliability-based design optimization (MORBDO). For considering the uncertainty propagation of reliable constraints, sequential statistical modeling is employed to estimate the appropriate distribution of probabilistic design variables. The present study also applies a multiresponse performance index based on the dimension reduction technique with a quality loss function. After verifying the MORBDO results using simulations on numerical problem, these techniques are applied to an automotive engine mounting system in the hierarchically decomposed problem of minimizing both the difference between the torque roll axis and the elastic roll axis and also the vibration transmissibility under mode purity and frequency requirements. The probabilistic design results indicate that the MORBDO results successfully identify more reliable and conservative optimized solutions than the deterministic results for a given reliability, and the failure probability is compared using a Monte Carlo simulation.

A Study of the Rolling Load Calculation Models for Flat Cold Rolling Process

Abstract. In order to keep the rolling products free of defects, the calculation and constant assessment of the rolling load and torque are required. Many theories for rolling load calculation were developed and among them the most used nowadays still are the Bland and Ford ’s (1948) model and Alexander’s (1971) model in order to achieve a better online control for reversible and tandem cold rolling mills. In this work those models were implemented in a numerical calculation software. The elastic roll’s deformation was taken into account using the Hitchcock´s formula for the deformed roll radius in an iterative way. Those models state that the friction hill (or normal pressure) in the contact arc keeps circular after the elastic deformation. This hypothesis is analysed with a third offline model for calculating the rolling load, named Noncirc (Shigaki et al., 2015), that considers the real roll elastic deformation (not circular anymore). Two cold rolling cases were considered and the friction coefficient was varied in order to evaluate the influence of this parameter on the calculated rolling load/width, the contact arc length and profile and pressure distribution over the contact arc. It was found that both models present imprecise results for both cases analysed, as the thickness is very low and the strip is very work hardened. The noncircular model shows higher loads and larger arc of contacts, but has the drawback of being offline. Keywords: Rolling load, Cold rolling, Friction hill, Noncircular arc.

Finite Element Analysis of cold pilgering using elastic roll dies

A finite element model of cold pilgering with elastic roll dies have been developed and used to investigate the influence of roll die deformation on the material flow, contact region, roll separati ...

A Complementarity Problem–Based Solution Procedure for 2D Steady-State Rolling Contacts with Dry Friction

ABSTRACTThe problem of steady-state rolling contact between two cylinders with dry friction was formulated into standard linear complementarity problems (LCPs) using the explicit physical definition. For normal contacts, the complementarity variables are the normal pressure and the gap. For the tangential contact, the traction distribution and relative slip are the variables obtained by solving the LCP. The frictional behavior is assumed to be governed by the Coulomb friction law, and LCP formulations of both similar elastic (Carter problem) and dissimilar elastic rolling contacts are presented in this work. Good agreement was found between the current LCP approach and publicly available software for both the rolling contact of similar elastic and dissimilar elastic cylinders. Moreover, the surface roughness was taken into account in this article by the verified approach. The results show the initial slope of the traction-relative creepage curve decreases as the surface roughness increases.

Mode decoupling concepts of an engine mount system for practical application

In recent years, appropriate engine mount system design has become increasingly important due to a consistent trend towards lighter car bodies combined with more power-intensive engines and often lower idle speed. Decoupling dominant vibration directions of the engine-gearbox assembly (EGA) from input excitation direction, in particular based on elastic axis decoupling and torque roll axis decoupling concepts, are often referred to in literature. However, their practical application remains scarce. Hence, multi-body system dynamics simulation and numerical optimization is used in order to introduce an easily applicable implementation of the referred concepts. Therefore, the modal kinetic energy distribution of the EGA with respect to physical directions is considered. Effects of coupling or decoupling of EGA eigenmodes regarding engine-excited (e.g. from engine run-up or idling) as well as road-induced vibrations (e.g. from rough road or cobblestones) are addressed in an engine mount system parameter design study for a small-sized engine. Decoupling modal kinetic energy fractions of all rigid body modes considerably reduces effects from engine-excited vibrations, while strong coupling might offer benefits for road-induced vibrations. As modal kinetic energy fractions can easily be varied by means of optimization and/or by using findings from correlation coefficients derived with design of experiment methods, the adaptation of design parameters (mount positions and inclinations, stiffnesses, and loss angles) is possible in a quite straightforward manner for an effective compromise.

Influence of the alignment of load and oscillation on the frictional shakedown of an elastic rolling contact with Coulomb friction

We examine frictional shakedown of a three dimensional elastic rolling contact. Slight oscillatory rolling of one contacting body varies the normal pressure distribution. In turn this causes incremental sliding processes and a macroscopic rigid body motion. We consider two settings: tangential force and rolling direction aligned parallel and perpendicular to each other. In both cases, the slip ceases after the first few periods and a safe shakedown occurs if the oscillation is sufficiently small. Otherwise ratcheting occurs and the accumulated slip leads to a continuing rigid body motion.