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.

scholarly journals Evaluation of the behavior system locator associated with a removable partial denture, finite element analysis

2018 ◽  
Vol 25 (2) ◽  
pp. 10
Author(s):  
Medardo Alexander Arenas-Chavarria ◽  
Samuel David Giraldo-Gómez ◽  
Federico Latorre-Correa ◽  
Junes Abdul Villarraga-Ossa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Deformation ◽  
Vertical Direction ◽  
Cobalt Chromium ◽  
Removable Partial Denture ◽  
Element Analysis ◽  
Partial Denture ◽  
Solid Works ◽  
Von Mises

Aim: The purpose of this research was to evaluate the behavior of the system locator settings associated with distal extension removable partial denture lower (PPR) by finite element analysis (FEA). Materials and Methods: A Class II Kennedy 3D model using a CAD software Solid Works 2010 (SolidWorks Corp., Concord, MA, USA), and subsequently processed and analyzed by ANSYS Software version Model 14. One (1) was designed implant Tapered Screw -Vent® (ref TSVB10 Zimmer Dental-Carlsbad,CA,USA.) length x 10mm diameter 3.7mm with a 3.5mm platform, internal hexagon with its respective screw fixation; this was located at the tooth 37 as a rear pillar of a PPR, whose major connector was a lingual bar casting (alloy cobalt chromium), based combined (metal/ acrylic) with teeth to replace (37, 36 and 35). Efforts were evaluated von Mises in a 400N load. This analysis allowed assessing the performance of various prosthetic structures modeled and generated effects on bone-implant interface. Results: Differences between the values von Mises in all structures and loads were observed before there was no permanent deformation in any of them. Structures such as bone showed in normal values microstrain. Conclusions: The behavior of the PPRimplant connection, showed a favorable distribution efforts by using a PPR, subjecting it to load in the vertical direction.

Comprehending Occurrence of Premature Failure in Compressor Turbine (CT) Blades for Short-Haul Aircraft Fleet

2019 ◽  
Vol 42 ◽  
pp. 10-23
Author(s):  
Joshua Kimtai Ngoret ◽  
Venkata Parasuram Kommula
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Thermal Stresses ◽  
Geometrical Model ◽  
Mechanical Stresses ◽  
Element Analysis ◽  
Premature Failure ◽  
Structural Stresses ◽  
Transient Thermal

This paper presents results from modeling of Compressor Turbine (CT) blades for short-haul aircraft fleet occasioned by thermo-mechanical stresses in order to comprehend the occurrence of premature failure. A 3D PT6A-114A engine high pressure (HP) CT blade geometrical model was developed in commercial CAD-SolidWorks, then imported to ANSYS 15.0 environment for finite element analysis (FEA). The CT blade was investigated for transient thermal stresses from heat generated by the combustors and static structural stresses from rotational velocities of the engine which account for 80% of inertial field during flight. The results revealed that the blades could have served for another 1.44% of the time they were in service.

scholarly journals Finite Element Analysis Of Airfield Flexible Pavement

2014 ◽  
Vol 60 (3) ◽  
pp. 323-334 ◽  
Author(s):  
G. Leonardi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
3D Model ◽  
Numerical Study ◽  
Permanent Deformation ◽  
Flexible Pavement ◽  
Finite Element Code ◽  
Element Analysis ◽  
Pavement Response ◽  
The Impact

Abstract The paper presents a numerical study of an aircraft wheel impacting on a flexible landing surface. The proposed 3D model simulates the behaviour of flexible runway pavement during the landing phase. This model was implemented in a finite element code in order to investigate the impact of repeated cycles of loads on pavement response. In the model, a multi-layer pavement structure was considered. In addition, the asphalt layer (HMA) was assumed to follow a viscoelastoplastic behaviour. The results demonstrate the capability of the model in predicting the permanent deformation distribution in the asphalt layer.

Uniform Design and Dynamic Finite Element Analysis for Permanent Deformation Improvement of an On-Road Bicycle Frame Undergoing the Drop-Mass Impact Test

2014 ◽  
Vol 933 ◽  
pp. 229-234 ◽  
Author(s):  
Yung Chang Cheng ◽  
Cheng Kang Lee ◽  
Cho Pei Jiang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Test ◽  
Permanent Deformation ◽  
Uniform Design ◽  
Element Analysis ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Drop Mass ◽  
Bicycle Frame

The purpose of this paper is to present the use of uniform design of experiments method and dynamic finite element analysis in improving the permanent deformation of an on-road bicycle frame which undergoes the drop-mass impact test. Firstly, four dimensional parameters of the bicycle frame are selected as the control factors to be improved. Then, uniform design method is used to construct a set of experiments. Each experiment denotes a specific design of frame. Next, for each experiment, the dynamic finite element analysis package ANSYS/LS-DYNA is employed to simulate the behavior of bicycle frame which undergoes the drop-mass impact test and determine the permanent deformation of the frame. Lastly, the best frame of all the experiments which causes the smallest permanent deformation is selected as the improved version of design. Compared with the original design which causes a permanent deformation of 8.458 mm, the improved version causes a permanent deformation of 7.467 mm. The rate of improvement is 11.7 %.

Failure Analysis of a Die for Cold Precision Forging of Bevel Gears

2008 ◽  
Vol 44-46 ◽  
pp. 779-786
Author(s):  
Jun Song Jin ◽  
Ju Chen Xia ◽  
Xin Yun Wang ◽  
Hua Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Corner Crack ◽  
Premature Failure ◽  
Bevel Gears ◽  
Precision Forging ◽  
Bottom Hole ◽  
Cold Precision Forging ◽  
Reduce Stress Concentration

The life of bevel gear dies is determined by its stress state mainly. During the forging, the die teeth fractured and the bottom corner cracked in a few times. Finite Element Analysis (FEA) was employed to investigate the reason of failure. The results show that the tip fracture and the bottom corner crack mainly resulted from excessive tensile stress. In accordance with the FEA results, the non-plane parting face was changed into plane parting face and the radius of bottom hole was enlarged. The FEA result proves that the modification can greatly reduce stress concentration and the application proves that the modification can effectively solve the premature failure of the die.

Slip Blinds at Pressures Causing Permanent Deformation

2006 ◽  
Vol 129 (2) ◽  
pp. 248-253
Author(s):  
Jaan Taagepera ◽  
Trevor G. Seipp
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Deformation ◽  
Nonlinear Finite Element Analysis ◽  
Nonlinear Finite Element ◽  
Working Environment ◽  
Hazardous Substances ◽  
Element Analysis ◽  
Work Area ◽  
Safe Working

Slip blinds are frequently used for hydrotesting piping. In addition, when maintaining equipment or piping, the equipment or piping must be isolated to ensure a safe working environment. Separating flange pairs and inserting a blind flange against the process side prevents hazardous substances from entering the work area. Slip blinds are often used for this type of service. However, slip blinds are generally limited to low-pressure service since at excessive pressures the blind will become dished and may leak or become impossible to remove. For this paper, slip blinds of various sizes and thicknesses were hydrostatically tested to determine their deformation as a function of pressure. Nonlinear finite element analysis (FEA) was used to analytically determine the deformation of slip blinds. The goal of the testing and FEA was to determine allowable pressures that would limit permanent deformation of the blinds to specified values.

Sign in / Sign up

Export Citation Format

Share Document