scholarly journals Brittle interfacial cracking between two dissimilar elastic layers: Part 1—Analytical development

2015 ◽  
Vol 134 ◽  
pp. 1076-1086 ◽  
Author(s):  
C.M. Harvey ◽  
J.D. Wood ◽  
S. Wang
Keyword(s):  
Analytical Development ◽  
Elastic Layers

Analytical Development of an Experimental Paradigm for C(3) Organizations

1988 ◽  
Author(s):  
Alexander H. Levis ◽  
Jeff T. Casey ◽  
Anne-Claire Louvet
Keyword(s):  
Experimental Paradigm ◽  
Analytical Development

scholarly journals Micro-mechanical investigation of railway ballast behavior under cyclic loading in a box test using DEM: effects of elastic layers and ballast types

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Early Stage ◽  
Damage Model ◽  
Simulation Models ◽  
Railway Track ◽  
Maintenance Cost ◽  
Particle Movement ◽  
Railway Ballast ◽  
Elastic Layers ◽  
The Impact

Abstract Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers are increasingly used for improving ballasted tracks. In order to better understand the effects of elastic layers, physical understanding at the ballast particle level is crucial. Here, discrete element method (DEM) is used to investigate the effects of elastic layers – under sleeper pad ($$\text {USP}$$USP) at the sleeper/ballast interface and under ballast mat ($$\text {UBM}$$UBM) at the ballast/bottom interface – on micro-mechanical behavior of railway ballast. In the DEM model, the Conical Damage Model (CDM) is used for contact modelling. This model was calibrated in Suhr et al. (Granul Matter 20(4):70, 2018) for the simulation of two different types of ballast. The CDM model accounts for particle edge breakage, which is an important phenomenon especially at the early stage of a tamping cycle, and thus essential, when investigating the impact of elastic layers in the ballast bed. DEM results confirm that during cyclic loading, $$\text {USP}$$USP reduces the edge breakage at the sleeper/ballast interface. On the other hand, $$\text {UBM}$$UBM shows higher particle movement throughout the ballast bed. Both the edge breakage and particle movement in the ballast bed are found to influence the sleeper settlement. Micro-mechanical investigations show that the force chain in deeper regions of the ballast bed is less affected by $$\text {USP}$$USP for the two types of ballast. Conversely, dense lateral forces near to the box bottom were seen with $$\text {UBM}$$UBM. The findings are in good (qualitative) agreement with the experimental observations. Thus, DEM simulations can aid to better understand the micro-macro phenomena for railway ballast. This can help to improve the track components and track design based on simulation models taking into account the physical behavior of ballast. Graphical Abstract

Bounds on the Maximum Contact Stress of an Indented Elastic Layer

1971 ◽  
Vol 38 (3) ◽  
pp. 608-614 ◽  
Author(s):  
Y. C. Pao ◽  
Ting-Shu Wu ◽  
Y. P. Chiu
Keyword(s):  
Half Space ◽  
Contact Stress ◽  
Elastic Layer ◽  
Theory Of Elasticity ◽  
Contact Conditions ◽  
Practical Applications ◽  
Method Of Solution ◽  
Elastic Layers ◽  
Maximum Contact ◽  
Contact Stress Distribution

This paper is concerned with the plane-strain problem of an elastic layer supported on a half-space foundation and indented by a cylinder. A study is presented of the effect of the contact condition at the layer-foundation interface on the contact stresses of the indented layer. For the general problem of elastic indenter or elastic foundation, the integral equations governing the contact stress distribution of the indented layer derived on the basis of two-dimensional theory of elasticity are given and a numerical method of solution is formulated. The limiting contact conditions at the layer-foundation interface are then investigated by considering two extreme cases, one with the indented layer in frictionless contact with the half space and the other with the indented layer rigidly adhered to the half space. Graphs of the bounds on the maximum normal stress occurring in indented elastic layers for the cases of rigid cylindrical indenter and rigid half-space foundation are obtained for possible practical applications. Some results of the elastic indenter problem are also presented and discussed.

Experimental and analytical development of health management for Electro-Mechanical Actuators

2009 ◽  
Author(s):  
Matthew J. Smith ◽  
Carl S. Byington ◽  
Matthew J. Watson ◽  
Sudarshan Bharadwaj ◽  
Genna Swerdon ◽  
...  
Keyword(s):  
Health Management ◽  
Analytical Development

Compressive Behavior of Multiply Delaminated Composite Laminates Part 1: Experiment and Analytical Development

AIAA Journal ◽  
10.2514/2.511 ◽  
1998 ◽  
Vol 36 (7) ◽  
pp. 1279-1285 ◽  
Author(s):  
Hiroshi Suemasu ◽  
Tatsuya Kumagai ◽  
Katsuhisa Gozu
Keyword(s):  
Composite Laminates ◽  
Compressive Behavior ◽  
Analytical Development

scholarly journals Available options for doing more with less: laboraory automation as one tool in the arsenal

1998 ◽  
Vol 20 (3) ◽  
pp. 87-89
Author(s):  
Stephen Scypinski ◽  
John Baiano ◽  
Theodore Sadlowski
Keyword(s):  
Laboratory Automation ◽  
Drug Discovery Process ◽  
Contract Research Organization ◽  
Advantages And Disadvantages ◽  
Line Extensions ◽  
Use Of Resources ◽  
Analytical Development ◽  
Effective Use ◽  
Case Basis

Projects that require analytical support can evolve from a number of different situations, for example new molecular entities from drug discovery; process changes; packaging changes; site changes; line extensions; and inlicensed projects and compounds. Laboratory automation has been shown to provide a viable and practical solution to assisting in analytical development. However, it is not always the most logical answer. A truly flexible and responsive analytical unit will make a decision on a case-by-case basis, when faced with a new project, whether it is best to: automate some or all aspects/testing involved; contract out to a reputable and approved contract research organization (CRO); hire temporary help; use available in-house resources; use a combination of the options shown above (for example to evaluate the complexity of the new project versus what the in-house resources are currently working on). The paper discusses the advantages and disadvantages of the various options with respect to providing analytical support and suggests optionsfor the most effective use of resources. The role of automation as one of the important tools in the arsenal of these options is highlighted.

scholarly journals Cell Force Microscopy on Elastic Layers of Finite Thickness

2007 ◽  
Vol 93 (9) ◽  
pp. 3314-3323 ◽  
Author(s):  
Rudolf Merkel ◽  
Norbert Kirchgeßner ◽  
Claudia M. Cesa ◽  
Bernd Hoffmann
Keyword(s):  
Finite Thickness ◽  
Force Microscopy ◽  
Elastic Layers ◽  
Cell Force
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