A Method to Estimate Isothermal Creep under Arbitrary Uniaxial Stress-Reversals

1986 ◽  
pp. 719-724
Author(s):  
M. Partl ◽  
A. Rösli
Keyword(s):  
Uniaxial Stress ◽  
Isothermal Creep ◽  
Stress Reversals

Two- and three-photon spectroscopy of ZnO under uniaxial stress

1998 ◽  
Vol 184-185 (1-2) ◽  
pp. 686-690 ◽  
Author(s):  
J Wrzesinski
Keyword(s):  
Uniaxial Stress

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.

Quantification of vertical, lateral, and longitudinal fastener demand in broken spike track: Inputs to mechanistic-empirical design

2021 ◽  
pp. 095440972110307
Author(s):  
Marcus S Dersch ◽  
Matheus Trizotto ◽  
J Riley Edwards ◽  
Arthur de Oliveira
Keyword(s):  
Fatigue Life ◽  
Design Principles ◽  
Lateral Load ◽  
System Component ◽  
Applied Loading ◽  
Component Design ◽  
Stress Reversals ◽  
Fatigue Failures ◽  
Empirical Design

To address a recent challenge related to broken spikes in premium elastic fastening systems that have led to at least ten derailments and require manual walking inspections as well as build upon mechanistic-empirical (M-E) design principles for future fastening system component design, this paper quantifies the vertical, lateral, and longitudinal fastening system loads under revenue service traffic in a curve that has regularly experienced spike fastener fatigue failures. Previous data has indicated that the high rail of Track 3 experienced the most failures at this location. The data from this investigation sheds light into why failures are more predominant at this location than others and how the vertical, lateral, and longitudinal loads cannot be considered independently. Specifically, while the magnitude of the applied loading was the lowest on the high rail of Track 3, the threshold for failure was also the lowest given the operations at this location led to unloading of the high rail, thus indirectly highlighting the importance of friction within a fastening system. The data also show the high rail of Track 3 was subjected to the highest L/V load ratios and was an outlier in the typical lateral load reversals applied likely leading to spike stress reversals and thus a shorter fatigue life. Finally, based upon the data, it is recommended that to mitigate spike failures, as well as similar fastener challenges in other track types (e.g. rail seat deterioration, etc.) railroads should ensure trains operate close to the balance speed and use fastening system that transfer loads through friction. This study also provides novel data for M-E design of fastening systems.

Uniaxial stress dependence of time-resolved electronic raman scattering in germanium

1996 ◽  
Vol 33 (1-3) ◽  
pp. 121-124
Author(s):  
Hideyuki Ohtake ◽  
Koichiro Tanaka ◽  
Takeyo Tsukamoto ◽  
Tohru Suemoto
Keyword(s):  
Raman Scattering ◽  
Uniaxial Stress ◽  
Stress Dependence ◽  
Time Resolved ◽  
Electronic Raman Scattering

scholarly journals S235JRC+C Steel Response Analysis Subjected to Uniaxial Stress Tests in the Area of High Temperatures and Material Fatigue

2021 ◽  
Vol 13 (10) ◽  
pp. 5675
Author(s):  
Josip Brnic ◽  
Marino Brcic ◽  
Sebastian Balos ◽  
Goran Vukelic ◽  
Sanjin Krscanski ◽  
...  
Keyword(s):  
High Temperatures ◽  
Room Temperature ◽  
Uniaxial Stress ◽  
Fatigue Tests ◽  
Experimental Investigations ◽  
Response Analysis ◽  
Stress Tests ◽  
Staircase Method ◽  
Mechanical Fatigue ◽  
Proper Material

Knowledge of the properties and behavior of materials under certain working conditions is the basis for the selection of the proper material for the design of a new structure. This paper deals with experimental investigations of the mechanical properties of unalloyed high quality steel S235JRC + C (1.0122) and its behavior under conditions of high temperatures, creep and mechanical fatigue. The response of the material at high temperatures (20–700 °C) is shown in the form of engineering stress-strain diagrams while that at creep behavior (400–600 °C) is shown in the form of creep curves. Furthermore, based on uniaxial fully reversed mechanical fatigue tests (R=−1), a stress-life (S-N) fatigue diagram has been constructed and the fatigue (endurance) limit of the material is calculated The experimentally determined value of tensile strength at room temperature is 534 MPa. The calculated value of the fatigue limit, also at room temperature, using the modified staircase method and based on the mechanical fatigue tests data, is 202 MPa. With regard to creep resistance, steel 1.0122 can be considered creep-resistant only at a temperature of 400 °C and at an applied stress not exceeding 50% of the yield strength corresponding to this temperature.

Uniaxial stress device for use with a SQUID magnetometer

1985 ◽  
Vol 56 (1) ◽  
pp. 125-130 ◽  
Author(s):  
D. P. Osterman ◽  
S. J. Williamson
Keyword(s):  
Uniaxial Stress ◽  
Squid Magnetometer
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