Stressed state of bodies with thermal cylindrical inclusions and cracks (plane deformation)

2010 ◽  
Vol 46 (3) ◽  
pp. 315-324 ◽  
Author(s):  
H. S. Kit ◽  
M. S. Chernyak
Keyword(s):  
Stressed State ◽  
Plane Deformation ◽  
Cylindrical Inclusions

Delamination in the scoring and folding of paperboard

TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 61-66 ◽  
Author(s):  
DOEUNG D. CHOI ◽  
SERGIY A. LAVRYKOV ◽  
BANDARU V. RAMARAO
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Strain Analysis ◽  
Local Strain ◽  
Uniaxial Stress ◽  
Material Model ◽  
Element Model ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Strain Fields

Delamination between layers occurs during the creasing and subsequent folding of paperboard. Delamination is necessary to provide some stiffness properties, but excessive or uncontrolled delamination can weaken the fold, and therefore needs to be controlled. An understanding of the mechanics of delamination is predicated upon the availability of reliable and properly calibrated simulation tools to predict experimental observations. This paper describes a finite element simulation of paper mechanics applied to the scoring and folding of multi-ply carton board. Our goal was to provide an understanding of the mechanics of these operations and the proper models of elastic and plastic behavior of the material that enable us to simulate the deformation and delamination behavior. Our material model accounted for plasticity and sheet anisotropy in the in-plane and z-direction (ZD) dimensions. We used different ZD stress-strain curves during loading and unloading. Material parameters for in-plane deformation were obtained by fitting uniaxial stress-strain data to Ramberg-Osgood plasticity models and the ZD deformation was modeled using a modified power law. Two-dimensional strain fields resulting from loading board typical of a scoring operation were calculated. The strain field was symmetric in the initial stages, but increasing deformation led to asymmetry and heterogeneity. These regions were precursors to delamination and failure. Delamination of the layers occurred in regions of significant shear strain and resulted primarily from the development of large plastic strains. The model predictions were confirmed by experimental observation of the local strain fields using visual microscopy and linear image strain analysis. The finite element model predicted sheet delamination matching the patterns and effects that were observed in experiments.

Bending of sheets and profiles on a four-roll machine for rocket bodies, tube and frame products. Part 4

2020 ◽  
pp. 45-54
Author(s):  
V.A. Zharkov
Keyword(s):  
Mathematical Model ◽  
Stressed State ◽  
Sheet Stamping ◽  
Formation Of Cracks ◽  
Processing Steps

A theory and a mathematical model are developed for calculating the parameters of the strain-stressed state at the stages of pre-bending, calibration, straightening and bending of the straightened section, taking into account the strengthening of the billet on a roll machine. By CAD/CAE modeling the strains, stresses and forces acting on the billet from the rolls are investigated. Criteria for the formation of cracks, low accuracy and excessive springing of the billet after these processing steps are determined, recommendations are given for their elimination. Keywords billet, sheet stamping, bending, roll machine, pre-bending, calibration, straightening, bending of the straightened section, CAD/CAE modeling. [email protected]

Improved anisotropy and piezoelectricity by applying in-plane deformation in monolayer WS2

2021 ◽  
Author(s):  
Ling Li ◽  
Peiting Wen ◽  
Yujue Yang ◽  
Nengjie Huo ◽  
Jingbo Li
Keyword(s):  
Plane Deformation ◽  
New Strategy

This study demonstrates a new strategy to engineer monolayer WS2 by applying in-plane deformation for larger anisotropy and superior piezoelectricity.

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