scholarly journals Nonlinear mechanical model of the shaft of a roll forming mill and parameter identification

2021 ◽  
Vol 112 (11-12) ◽  
pp. 3363-3375
Author(s):  
Matthias Lamprecht ◽  
Emin Koçbay ◽  
Martin Leonhartsberger ◽  
Yury Vetyukov ◽  
Friedrich Bleicher
Keyword(s):  
Continuous Process ◽  
Theoretical Models ◽  
Element Model ◽  
Rolling Process ◽  
Metal Sheet ◽  
Effective Length ◽  
Roll Forming ◽  
Beam Model ◽  
Compliant Part ◽  
Final Profile

AbstractRoll forming is a continuous process in which a moving metal sheet passes through numerous pairs of opposing forming rolls. The shafts of the roll forming mill are equipped with these rolls and must be set up and aligned to achieve the required final profile of the sheet. The practically relevant task of predicting the profile geometry of this incremental rolling process with varying characteristics of the metal sheet entering the mill requires an accurate description of the stiffness behavior of the shaft with rolls, which is the most compliant part of the roll forming mill. In this paper, the measured force-deflection characteristic of the shaft without rolls is compared with predictions of various theoretical models, followed by the adoption of the shear deformable beam model of the shaft with nonlinear elastic supports in the bearings. The coefficients of the cubic stiffness characteristics of the rotational springs as well as the effective length between the supports are identified based on the experimental data for the deflections, measured along the shaft for various loading levels. The theoretical predictions are obtained via the nonlinear finite element model of the shaft. The model thus provided shows high accuracy compared with the measurements. The paper’s results serve as a foundation for models to predict the stiffness of shafts with rolls.

Dynamic Parameters Identification of Structural Laminated Glass

2015 ◽  
Author(s):  
Francesco Clementi ◽  
Laura Consolini ◽  
Stefano Lenci
Keyword(s):  
Natural Frequencies ◽  
Theoretical Models ◽  
Element Model ◽  
Free Vibrations ◽  
Laminated Glass ◽  
Beam Model ◽  
Dynamical Characteristics ◽  
Time Histories ◽  
Dynamical Properties

In this work, we address experimentally the determination of the dynamical properties, in particular natural frequencies and damping factors, of laminated structural glass. Various specimens, coming from different productions and manufactures, are investigated. Damped free vibrations experiments are performed, where the excitation is provided by an instrumented hammer. The boundary conditions are free-free (the specimens lay on a very flexible sponge substrate). The dynamical characteristics are determined by last squares fitting of time histories, a technique that is very simple, fast and provides very good results. Finally, two theoretical models (a two-layer beam model and a 2D finite element model) are employed to interpret the experimental results.

Determining the Rayleigh damping parameters of flexible pavements for finite element modeling

2021 ◽  
pp. 107754632110267
Author(s):  
Jiandong Huang ◽  
Xin Li ◽  
Jia Zhang ◽  
Yuantian Sun ◽  
Jiaolong Ren
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Natural Frequencies ◽  
Least Squares Method ◽  
Element Model ◽  
Beam Model ◽  
Element Modeling ◽  
Rayleigh Damping ◽  
Damping Matrix

The dynamic analysis has been successfully used to predict the pavement response based on the finite element modeling, during which the stiffness and mass matrices have been established well, whereas the method to determine the damping matrix based on Rayleigh damping is still under development. This article presents a novel method to determine the two parameters of the Rayleigh damping for dynamic modeling in pavement engineering. Based on the idealized shear beam model, a more reasonable method to calculate natural frequencies of different layers is proposed, by which the global damping matrix of the road pavement can be assembled. The least squares method is simplified and used to calculate the frequency-independent damping. The best-fit Rayleigh damping is obtained by only determining the natural frequencies of the two modal. Finite element model and in-situ field test subjected by the same falling weight deflectometer pulse loads are performed to validate the accuracy of this method. Good agreements are noted between simulation and field in-situ results demonstrating that this method can provide a more accurate approach for future finite element modeling and back-calculation.

scholarly journals An Investigation into the Effect of Rolling Reduction on 3D Curved Parts Rolling Process

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1209
Author(s):  
Xiang Chang ◽  
Wenzhi Fu ◽  
Mingzhe Li ◽  
Xintong Wang ◽  
Weifeng Yang ◽  
...  
Keyword(s):  
Element Model ◽  
Rolling Process ◽  
Rolling Reduction ◽  
Shape Accuracy ◽  
Bending Deformation ◽  
Good Shape ◽  
Longitudinal Bending ◽  
Gap Height ◽  
Roll Gap ◽  
Forming Tools

Rolling technology based on arc-shaped rollers is a novel method for rapid manufacturing of 3D curved parts. The method uses a pair of arc-shaped rollers (a convex roller and a concave roller) as forming tools, forming an unevenly distributed roll gap. The sheet metal has both transverse bending and longitudinal uneven extension during rolling, so that surface parts with double curvature are processed. The curvature of the formed surface part can be changed by changing the rolling reduction. Changing the vertical distance between the rollers will cause the overall change of the roll gap height, which will inevitably have a great impact on the forming effect of formed 3D curved parts. In this paper, a finite element model and experiment with different rolling reductions was designed; the influence of rolling reduction on the bending deformation and shape accuracy of formed 3D curved parts was studied. The results show that, with the slight increase of rolling reduction (from 0.04 to 0.12 mm), the longitudinal bending deformation of the formed 3D curved part increases significantly, but its transversal bending is almost not affected. When the maximum rolling reduction is 0.04 and 0.06 mm (the corresponding minimum rolling reduction is less than or equal to zero), the shape accuracy of the formed 3D curved parts is not good enough; when the maximum rolling reduction is greater than 0.06 mm (the corresponding minimum rolling reduction is greater than zero), the shape accuracy of the formed 3D curved parts is significantly better. This indicates that, for the rolling of 3D curved parts based on arc-shaped rollers, ensuring that the minimum rolling reduction is greater than zero is the key to ensuring good shape accuracy of the formed 3D curved parts.

scholarly journals Variation Simulation of Fixtured Assembly Processes for Compliant Structures Using Piecewise-Linear Analysis

2005 ◽  
Author(s):  
Michael L. Stewart ◽  
Kenneth W. Chase
Keyword(s):  
Piecewise Linear ◽  
Element Model ◽  
Linear Analysis ◽  
Elastic Analysis ◽  
Variation Analysis ◽  
Linear Elastic ◽  
Final Assembly ◽  
Compliant Part ◽  
Assembly Operations ◽  
Variation Simulation

While variation analysis methods for compliant assemblies are becoming established, there is still much to be done to model the effects of multi-step, fixtured assembly processes statistically. A new method is introduced for statistically analyzing compliant part assembly processes using fixtures. This method yields both a mean and a variant solution, which can characterize an entire population of assemblies. The method, called Piecewise-Linear Elastic Analysis, or PLEA, is developed for predicting the residual stress, deformation and springback variation resulting from fixtured assembly processes. A comprehensive, step-by-step analysis map is presented for introducing dimensional and surface variations into a finite element model, simulating assembly operations, and calculating the error in the final assembly. PLEA is validated on a simple, laboratory assembly and a more complex, production assembly. Significant modeling issues are resolved as well as the comparison of the analytical to physical results.

Comparison Between the Effects of Zero and Non-Zero Flow Acceleration on the Entropy Wave Decay: An Experimental Study

2021 ◽  
Vol 143 (11) ◽  
Author(s):  
S. M. Hosseinalipour ◽  
E. Rahmani ◽  
A. Fattahi
Keyword(s):  
Hot Spot ◽  
Theoretical Models ◽  
Fast Response ◽  
Effective Length ◽  
Combustion Instabilities ◽  
Convergent Nozzle ◽  
Flow Acceleration ◽  
Wave Decay ◽  
Accelerated Flow ◽  
Effective Length Method

Abstract Entropy wave, as the convecting hot spot, is one of the sources of combustion instabilities, which is less explored through the literature. Convecting in a highly turbulent flow of a combustor, entropy waves may experience some levels of dissipation and deformation. In spite of some earlier investigations in the zero acceleration flow, the extent of the wave decay has not been clear yet. Further, there exist no results upon the wave decay in non-zero accelerated flows. This is of crucial importance, as the wave passes through the end nozzle of the combustor or gas turbine stages. The current experiment, therefore, compares the wave decay in both flow of constant and variable bulk velocity, meaning, respectively, a uniform pipe and a convergent nozzle. The comparison will aid the theoretical models to reduce complexity by simplifying the relations of non-zero acceleration flow to those of no acceleration, as followed by the earlier effective-length method. Reynolds number and inlet turbulence intensity are considered as the governing hydrodynamic parameters for both investigated flows. The entropy wave is generated by an electrical heater module and detected using fast-response thermocouples. The results show that the entropy wave variation is point-wise and frequency-dependent. The accelerated flow of the nozzle is generally found to be more dissipative in comparison with the zero acceleration flow.

scholarly journals Effect of Differential Speed Rotation Technology on the Forming Uniformity in Flexible Rolling Process

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1906 ◽  
Author(s):  
Yi Li ◽  
Mingzhe Li ◽  
Kai Liu ◽  
Zhuo Li
Keyword(s):  
Element Model ◽  
Rolling Process ◽  
Metal Plate ◽  
Curved Surface ◽  
Forming Process ◽  
Surface Part ◽  
Flexible Rolling ◽  
Speed Rotation ◽  
The One ◽  
Differential Speed

As the local forming non-uniform of the formed curved surface part with larger bending deformation is the one of common defects, the utilization ratio of metal plate greatly reduces due to this defect, and cost of production is also increasing. In this paper, the differential speed rotation technology of flexible rolling process was proposed firstly to solve this forming defect. The finite element model was established, the reason of the local forming non-uniform was discussed; the effect of differential speed rotation technology on the forming uniform was studied. The results show that: Flexible rolling is a process based on thickness reduction, in this forming process, the thickness reduces sharply near the back end of metal plate, the local forming non-uniform of formed curved surface part is caused during this process; the differential speed rotation technology is applied in flexible rolling, with increasing rotation speed difference between upper and lower roll set, the forming uniformity of the formed curved surface part is greatly improved. The results of numerical simulation are in agreement with the result of forming experiments.

Enhanced Comprehension of the Continuous Fusion Bonding Process of Multi-Material Structures

2018 ◽  
Vol 939 ◽  
pp. 197-204 ◽  
Author(s):  
Tobias Reincke ◽  
Sven Hartwig ◽  
Klaus Dilger
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Lightweight Design ◽  
Continuous Process ◽  
Peel Test ◽  
Roll Forming ◽  
Scale Production ◽  
Continuous Manufacturing ◽  
Fusion Bonding ◽  
Reinforced Thermoplastics

In comparison to monolithic composite structures, tailored multi-material structures offer high potential considering lightweight design approaches in combination with cost efficient manufacturing processes. Roll forming enables flexible large scale production of hybrid structures, due to the continuous manufacturing process as well as high degree of automation. The multi-material structures consist of steel sheets which are selectively reinforced by unidirectional carbon fibre reinforced thermoplastics (CFR-TP). In view of minimizing process steps and decreasing cycle times, both materials are joined by fusion bonding. Therefore, CFR-TP is heated above melting temperature of thermoplastic matrix and joined to the steel surface under defined pressure and time. However, joining of both materials within a continuous process is still challenging due to a lack in terms of process comprehension. Consequently, multi-material specimens were manufactured depending on various process parameters as temperature of either material or processing speed and tested mechanically by floating roller peel test for the evaluation of the adhesion between both materials. Furthermore, viscosity of matrix was determined and investigations of CFR-TP interface were performed by Fourier transform infrared spectroscopy. The results show the requirement of a defined CFR-TP temperature and the change in crystalline structure of the matrix in dependency of the processing.

A Quasi-Static Model for Studying Physical Interaction Between a Soft Robotic Digit and a Human Finger

2018 ◽  
Author(s):  
Mahdi Haghshenas-Jaryani ◽  
Muthu B. J. Wijesundara
Keyword(s):  
Human Performance ◽  
Theoretical Models ◽  
Element Model ◽  
Human Robot Interaction ◽  
Physical Interaction ◽  
Robotic Hand ◽  
Robot Interaction ◽  
Interaction Forces ◽  
Comparison Of The Results ◽  
Human Finger

This paper presents the development of a framework based on a quasi-statics concept for modeling and analyzing the physical human-robot interaction in soft robotic hand exoskeletons used for rehabilitation and human performance augmentation. This framework provides both forward and inverse quasi-static formulations for the interaction between a soft robotic digit and a human finger which can be used for the calculation of angular motions, interaction forces, actuation torques, and stiffness at human joints. This is achieved by decoupling the dynamics of the soft robotic digit and the human finger with similar interaction forces acting on both sides. The presented theoretical models were validated by a series of numerical simulations based on a finite element model which replicates similar human-robot interaction. The comparison of the results obtained for the angular motion, interaction forces, and the estimated stiffness at the joints indicates the accuracy and effectiveness of the quasi-static models for predicting the human-robot interaction.

Vibration Response of a Thin-Walled Cylindrical Pipe with Liquid

2012 ◽  
Vol 189 ◽  
pp. 345-349
Author(s):  
Yu Lan Wei ◽  
Bing Li ◽  
Li Gao ◽  
Ying Jun Dai
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Element Model ◽  
Beam Model ◽  
Vibration Modes ◽  
Timoshenko Beam Model ◽  
Cylindrical Pipe ◽  
Bending Vibration ◽  
Beam Bending ◽  
Thin Walled

Vibration characteristics of the thin-walled cylindrical pipe are affected by the liquid within the pipe. The natural frequencies and vibration modes of the pipe without liquid are analyzed by the theory of beam bending vibration and finite element model, which is based on the Timoshenko beam model. The first three natural frequencies and vibration modes of the pipe with or without liquid are acquired by experiments. As shown in the experiment results, the natural frequencies of the containing liquid pipe are lower than the natural frequencies of the pipe without liquid.

Tail Deviation Mechanism and Neural Network Control of the Tandem Rolling Strap

2011 ◽  
Vol 103 ◽  
pp. 488-492
Author(s):  
Guang Bin Wang ◽  
Xian Qiong Zhao ◽  
Yi Lun Liu
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Finite Element Model ◽  
Control Policy ◽  
Element Model ◽  
Rolling Process ◽  
Network Control ◽  
Neural Network Control ◽  
The Neural Network ◽  
The Finite Element Model

In the rolling process, deviation is the phenomenon that the strap width direction's centerline deviates from rolling system setting centerline,serious deviation will cause product quality drop and rolling equipment fault. This paper has established the finite element model to the hot tandem rolling aluminum strap, analyzed the strap’s deviation rule under four kinds of incentives,obtained the neural network predictive model and the control policy of the tail deviation.The result to analyze a set of fact deviation data shows this method may control tail deviation in preconcerted permission range.

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