Edge Buckling of Imperfectly Guided Webs

1998 ◽  
Vol 120 (2) ◽  
pp. 346-352 ◽  
Author(s):  
A. V. Lakshmikumaran ◽  
J. A. Wickert
Keyword(s):  
Plane Deformation ◽  
Free Edge ◽  
Laboratory Measurements ◽  
Angular Misalignment ◽  
Web Handling ◽  
State Of Stress ◽  
Out Of Plane ◽  
Metal Processing ◽  
The Stability ◽  
The Web

Web handling is germane to a diverse set of industries, including paper, polymer, textile, and sheet metal processing. Angular misalignment of the guides used to position a web in its transport system generates non-uniform in-plane forces that can result in transverse buckling of the web, even for misalignments as small as a fraction of a degree. In this paper, the state of stress, the associated in-plane deformation, out-of-plane vibration, and stability of webs with misaligned guides are investigated experimentally and theoretically. The onset of edge buckling, in which transverse corrugations are present along an entire free edge or are localized near a guide, is governed by the stability of a relatively high mode of the nominally aligned web. Two models of common web transport components—termed “free sliding” and “edge guided” —are developed and discussed in the light of laboratory measurements for predicting and bounding critical buckling angles.

scholarly journals Parametric Instability of a Traveling Plate Partially Supported by a Laterally Moving Elastic Foundation

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
V. Kartik ◽  
J. A. Wickert
Keyword(s):  
Data Storage ◽  
Parametric Instability ◽  
Primary Resonance ◽  
Free Edge ◽  
Moving Plate ◽  
Torsional Mode ◽  
Plane Vibration ◽  
Out Of Plane ◽  
Axially Moving ◽  
The Stability

The parametric excitation of an axially moving plate is examined in an application where a partial foundation moves in the plane of the plate and in a direction orthogonal to the plate’s transport. The stability of the plate’s out-of-plane vibration is of interest in a magnetic tape data storage application where the read/write head is substantially narrower than the tape’s width and is repositioned during track-following maneuvers. In this case, the model’s equation of motion has time-dependent coefficients, and vibration is excited both parametrically and by direct forcing. The parametric instability of out-of-plane vibration is analyzed by using the Floquet theory for finite values of the foundation’s range of motion. For a relatively soft foundation, vibration is excited preferentially at the primary resonance of the plate’s fundamental torsional mode. As the foundation’s stiffness increases, multiple primary and combination resonances occur, and they dominate the plate’s stability; small islands, however, do exist within unstable zones of the frequency-amplitude parameter space for which vibration is marginally stable. The plate’s and foundation’s geometry, the foundation’s stiffness, and the excitation’s amplitude and frequency can be selected in order to reduce undesirable vibration that occurs along the plate’s free edge.

Ultimate Behavior of Single Shear Bolted Connections with Thin-Walled Aluminum Alloys(6061-T6)

2012 ◽  
Vol 446-449 ◽  
pp. 3441-3445 ◽  
Author(s):  
Tae Soo Kim ◽  
Yong Hyun Jo ◽  
Seung Hun Kim ◽  
Yong Taeg Lee
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Plane Deformation ◽  
Free Edge ◽  
Fe Analysis ◽  
Test Results ◽  
Bolted Connections ◽  
Element Analysis ◽  
Out Of Plane ◽  
Single Shear

The purpose of this study is to investigate the ultimate behaviors of aluminum alloy bolted connections assembled with four bolts. Specimens for single shear bolted connections were tested and finite element analysis based on this test results was conducted. The validity of finite element(FE) analysis for predicting the structural behaviors such as ultimate strength, fracture mode and curling(out-of-plane deformation) occurrence was verified through the comparisons between test results and FE analysis results. It is known that the curling resulted in sudden strength drop. Moreover, FE models with free edge and restrained out-of-plane deformation for curled specimens are analyzed additionally, therefore, the influence of curling on the ultimate strength; strength reduction ratio is estimated.

Aeroelastic Stability of Axially Moving Webs Coupled to Incompressible Flows

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
Merrill Vaughan ◽  
Arvind Raman
Keyword(s):  
High Speed ◽  
Incompressible Flows ◽  
Mixed Boundary ◽  
Free Edge ◽  
Mode Shapes ◽  
Aeroelastic Stability ◽  
Machine Direction ◽  
Web Handling ◽  
Axially Moving ◽  
The Web

The aeroelastic flutter of thin flexible webs severely limits their transport speeds and consequently the machine throughputs in a variety of paper, plastics, textiles, and sheet metal industries. The aeroelastic stability of such high-speed webs is investigated using an assumed mode discretization of an axially moving, uniaxially tensioned Kirchhoff plate coupled with cross and machine direction flows of a surrounding incompressible fluid. The corresponding aerodynamic potentials are computed using finite element solutions of certain mixed boundary value problems that arise in the fluid domain. In the absence of air coupling, the cross-span mode frequencies tightly cluster together, and the web flutters via mode coalescence at supercritical transport speed. Web coupling to an initially quiescent incompressible potential flow significantly reduces the web frequencies, substantially modifies the mode shapes, and separates the frequency clusters, while only marginally affecting the flutter speed and frequency. The inclusion of machine direction base flows significantly modifies the web stability and mode shapes. Cross machine direction flows lead to the flutter with vanishing frequency of very high cross-span nodal number modes, and the unstable vibration naturally localizes at the leading free edge. These results corroborate several previous experimental results in literature and are expected to guide ongoing experiments and the design of reduced flutter web handling systems.

Parametric Instability of a Traveling Plate Partially Supported by a Laterally-Moving Foundation

2007 ◽  
Author(s):  
V. Kartik ◽  
J. A. Wickert
Keyword(s):  
Data Storage ◽  
Parametric Instability ◽  
Primary Resonance ◽  
Free Edge ◽  
Moving Plate ◽  
Torsional Mode ◽  
Plane Vibration ◽  
Out Of Plane ◽  
Axially Moving ◽  
The Stability

The parametric excitation of an axially-moving plate is examined in an application where a partial foundation moves in the plane of the plate and in a direction orthogonal to the plate’s transport. The stability of the plate’s out-of-plane vibration is of interest in a magnetic tape data storage application where the read/write head is substantially narrower than the tape’s width, and is repositioned during track following maneuvers. In this case, the model’s equation of motion has time-dependent coefficients, and vibration is excited both parametrically and by direct forcing. The parametric instability of out-of-plane vibration is analyzed by using the Floquet theory for finite values of the foundation’s range of motion. For a relatively soft foundation, vibration is excited preferentially at the primary resonance of the plate’s fundamental torsional mode. As the foundation’s stiffness increases, multiple primary and combination resonances occur, and they dominate the plate’s stability; small islands, however, do exist within unstable zones of the frequency-amplitude parameter space for which vibration is marginally stable. The plate’s and foundation’s geometry, the foundation’s stiffness, and the excitation’s amplitude and frequency can be selected in order to reduce undesirable vibration that occurs along the plate’s free edge.

scholarly journals Relationships between Imperfections and Shear Buckling Resistance in Web Plate with Sectional Damage Caused by Corrosion

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Jin-Hee Ahn ◽  
Shigenobu Kainuma ◽  
Won-Hong Lee ◽  
Youn-Ju Jeong ◽  
In-Tae Kim
Keyword(s):  
Aspect Ratio ◽  
Plane Deformation ◽  
Corrosion Damage ◽  
Fe Analysis ◽  
Analysis Model ◽  
Buckling Resistance ◽  
Out Of Plane ◽  
Shear Buckling ◽  
Simple Evaluation ◽  
The Web

This study deals with the relationship between imperfections and shear buckling resistance of web plates with sectional damage caused by corrosion. To examine the imperfection effect on the shear buckling resistance of a web plate with sectional damage, a series of nonlinear finite element (FE) analyses were carried out for a web plate with sectional damage, which was assumed as local corrosion damage. For considering imperfections of the web plate in the girder, initial out-of-plane deformation was introduced in the FE analysis model. Using the FE analysis results, the changes in the shear buckling resistance of the web plate with sectional damage were quantitatively examined and summarized according to the aspect ratio, boundary conditions, and height of the damaged section of the web plate. The effects of web imperfections on the shear buckling resistance were evaluated to be little compared to that of the web plate without sectional damage. The shear buckling resistance was shown to significantly change in the high-aspect-ratio web plate. A simple evaluation equation for the shear buckling resistance of a web plate with sectional damage was modified for use in the practical maintenance of a web plate in corrosive environments.

scholarly journals Characterization and ballistic performance of thin pre-damaged resin-starved aramid-fiber composite panels

2021 ◽  
pp. 004051752110134
Author(s):  
Cerise A Edwards ◽  
Stephen L Ogin ◽  
David A Jesson ◽  
Matthew Oldfield ◽  
Rebecca L Livesey ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Plane Deformation ◽  
Ballistic Impact ◽  
Image Correlation ◽  
Composite Panel ◽  
Composite Panels ◽  
Micro Computed Tomography ◽  
Ballistic Performance ◽  
Low Level ◽  
Out Of Plane

Military personnel use protective armor systems that are frequently exposed to low-level damage, such as non-ballistic impact, wear-and-tear from everyday use, and damage during storage of equipment. The extent to which such low-level pre-damage could affect the performance of an armor system is unknown. In this work, low-level pre-damage has been introduced into a Kevlar/phenolic resin-starved composite panel using tensile loading. The tensile stress–strain behavior of this eight-layer material has been investigated and has been found to have two distinct regions; these have been understood in terms of the microstructure and damage within the composite panels investigated using micro-computed tomography and digital image correlation. Ballistic testing carried out on pristine (control) and pre-damaged panels did not indicate any difference in the V50 ballistic performance. However, an indication of a difference in response to ballistic impact was observed; the area of maximal local out-of-plane deformation for the pre-damaged panels was found to be twice that of the control panels, and the global out-of-plane deformation across the panel was also larger.

scholarly journals In-Process Measurement of Three-Dimensional Deformations Based on Speckle Photography

2021 ◽  
Vol 11 (11) ◽  
pp. 4981
Author(s):  
Andreas Tausendfreund ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
Evaluation Method ◽  
Process Analysis ◽  
Plane Deformation ◽  
Three Dimensional ◽  
Machining Process ◽  
Image Correlation ◽  
Speckle Photography ◽  
Process Measurement ◽  
Out Of Plane ◽  
Plane Deformations

In the concept of the process signature, the relationship between a material load and the modification remaining in the workpiece is used to better understand and optimize manufacturing processes. The basic prerequisite for this is to be able to measure the loads occurring during the machining process in the form of mechanical deformations. Speckle photography is suitable for this in-process measurement task and is already used in a variety of ways for in-plane deformation measurements. The shortcoming of this fast and robust measurement technique based on image correlation techniques is that out-of-plane deformations in the direction of the measurement system cannot be detected and increases the measurement error of in-plane deformations. In this paper, we investigate a method that infers local out-of-plane motions of the workpiece surface from the decorrelation of speckle patterns and is thus able to reconstruct three-dimensional deformation fields. The implementation of the evaluation method enables a fast reconstruction of 3D deformation fields, so that the in-process capability remains given. First measurements in a deep rolling process show that dynamic deformations underneath the die can be captured and demonstrate the suitability of the speckle method for manufacturing process analysis.

Inverse algorithm for out-of-plane deformation in shearography

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Shuangle Wu ◽  
Fangyuan Sun ◽  
Haotian Xie ◽  
Qihan Zhao ◽  
Peizheng Yan ◽  
...  
Keyword(s):  
Plane Deformation ◽  
Inverse Algorithm ◽  
Out Of Plane

scholarly journals Out-of-plane local mechanism analysis with finite element method

2021 ◽  
Vol 8 (1) ◽  
pp. 130-136
Author(s):  
Roberto Spagnuolo
Keyword(s):  
Finite Element ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Mechanism Analysis ◽  
Fem Method ◽  
Local Mechanism ◽  
Out Of Plane ◽  
Smeared Crack ◽  
The Stability ◽  
No Tension Material

Abstract The stability check of masonry structures is a debated problem in Italy that poses serious problems for its extensive use. Indeed, the danger of out of plane collapse of masonry walls, which is one of the more challenging to evaluate, is traditionally addressed not using finite element models (FEM). The power of FEM is not properly used and some simplified method are preferred. In this paper the use of the thrust surface is suggested. This concept allows to to evaluate the eccentricity of the membrane stresses using the FEM method. For this purpose a sophisticated, layered, finite element with a no-tension material is used. To model a no-tension material we used the smeared crack method as it is not mesh-dependent and it is well known since the early ’80 in an ASCE Report [1]. The described element has been implemented by the author in the program Nòlian by Softing.

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