Compression moduli for blocks of soft elastic material bonded to rigid end plates

1979 ◽  
Vol 14 (1) ◽  
pp. 11-16 ◽  
Author(s):  
P B Lindley
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plane Strain ◽  
Elastic Material ◽  
Analysis Data ◽  
Theoretical Solution ◽  
Element Analysis ◽  
Incompressible Materials ◽  
Simplifying Assumptions ◽  
Poisson's Ratios

Using simplifying assumptions based on a theoretical solution for incompressible materials, simple relations are developed for the plane strain and axisymmetric compression moduli for blocks of compressible soft elastic material bonded to rigid end plates. The approximate theoretical solutions compare well with finite-element analysis data for materials with Poisson's ratios between 0.125 and 0.499 83 and blocks having width-to-thickness or diameter-to-thickness ratios between 0.25 and 128.

Plane strain rotation moduli for soft elastic blocks

1979 ◽  
Vol 14 (1) ◽  
pp. 17-21 ◽  
Author(s):  
P B Lindley
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plane Strain ◽  
Elastic Material ◽  
Analysis Data ◽  
Simple Relation ◽  
Theoretical Solution ◽  
The Other ◽  
Element Analysis ◽  
Poisson's Ratios

Making assumptions similar to these used to obtain compression moduli, a simple relation is developed for the plane strain rotation moduli for blocks of soft elastic material bonded to rigid end plates. The deformation arises when one plate rotates relative to the other plane about an axis along the centre of its width. The approximate theoretical solution compares well with finite-element analysis data for materials with Poisson's ratios of 0.333, 0.483 87 and 0.499 83 and blocks having width-to-thickness ratios between 0.25 and 64.

Ratchetting damage of railhead material of gapped rail joints with reference to free rail end effects

2016 ◽  
Vol 231 (2) ◽  
pp. 211-225 ◽  
Author(s):  
Nirmal Kumar Mandal
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Deformation ◽  
Equivalent Plastic Strain ◽  
Analysis Data ◽  
Material Degradation ◽  
Potential Threat ◽  
End Effects ◽  
Element Analysis ◽  
Premature Failure

Free ends of insulated rail joints occur because gaps between the rails and endposts can be created due to pull-apart problems as the rails contract longitudinally in winter and by degradation of railhead material. Dynamic behaviour of gapped rail joints changes adversely compared to that of insulated rail joints. Thus, material degradation and damage of gapped rail joint components such as rail ends, joint bars, etc. are accelerated. Only limited literatures are available addressing the free end of rail effects at rail joints, targeting stress and pressure distributions in the vicinity of the rail joints. To understand clearly the material degradation and delamination process of gapped rail joints, a thorough analysis of failure of both insulated rail joints and gapped rail joints and subsequent damage of the railhead material is necessary to improve the service life of these joints. A new three-dimensional finite element analysis is carried out in this paper to assess damage to railhead material when gapped rail joints form. Both narrow (5 mm) and wide (10 mm) gaps are considered, using a peak vertical pressure load of 2500 MPa applied cyclically at one rail end, forming vertical impacts. Stress distributions and plastic deformations in the vicinity of gapped rail joints are quantified using finite element analysis data and compared with that of the insulated rail joints to show the effects of free rail ends. Residual stress and strain distributions indicate the damage to the railhead material. Equivalent plastic strain (PEEQ) quantifies the progressive damage to the railhead material at the rail ends. The free end of rail effects can be further illustrated by comparing PEEQ for insulated rail joints and gapped rail joints. The railhead material of 5 and 10 mm gapped rail joints is more sensitive to permanent deformation compared to that of the corresponding insulated rail joints. Therefore, free rail end joints pose an increased potential threat to rail operations in relation to crack initiation, damage and premature failure of railhead material.

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