Fatigue life of the welding seam of a tracked vehicle body structure evaluated using the structural stress method

2021 ◽  
Vol 120 ◽  
pp. 105102
Author(s):  
Ke Bao ◽  
Qing Zhang ◽  
Yue Liu ◽  
Jin Dai
Keyword(s):  
Fatigue Life ◽  
Vehicle Body ◽  
Structural Stress ◽  
Body Structure ◽  
Tracked Vehicle ◽  
Welding Seam

STRUCTURAL STRESS METHOD FOR FATIGUE DESIGN OF CONCRETE FILLED STEEL TUBULAR T-JOINTS UNDER AXIAL LOADING

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Idris A. Musa
Keyword(s):  
Fatigue Life ◽  
Three Dimensional ◽  
Axial Loading ◽  
Fe Model ◽  
Structural Stress ◽  
Stress Concentrations ◽  
Engineering Structures ◽  
T Joints ◽  
Tubular Joints ◽  
Concrete Filling

Steel tubular structural members are being widely used in various engineering structures. The steel tubular joints will have fatigue problem when subjected to repetitive loading. Fatigue strength is one of the key factors that control the design of steel tubular joints in structures subjected to frequent loading. Research has shown that concrete filling of the steel tubes can effectively reduce stress concentrations at the joint. In this study, the structural stress method which involves the through-thickness stress distribution, has been employed to estimate the fatigue life of concrete filled steel tubular (CFST) T-joints under axial loading in the brace. A Finite Element (FE) model has been developed using ABAQUS. The three-dimensional 8-node hexahedral element has been employed in the FE model. The structural stresses have been extracted and the fatigue life of the joint has been estimated. The results have been verified using experimental results reported in the literature. The current study showed that the structural stress method can effectively predict reliable fatigue life in concrete filled steel tubular (CFST) T-joints.

scholarly journals Influence of Weld Parameters on the Fatigue Life of Deck-Rib Welding Details in Orthotropic Steel Decks Based on the Improved Stress Integration Approach

2019 ◽  
Vol 9 (18) ◽  
pp. 3917 ◽  
Author(s):  
Baoya Cao ◽  
Youliang Ding ◽  
Zhao Fang ◽  
Fangfang Geng ◽  
Yongsheng Song
Keyword(s):  
Fatigue Life ◽  
Mesh Size ◽  
Structural Stress ◽  
Partial Penetration ◽  
Full Penetration ◽  
Integration Approach ◽  
Treatment Type ◽  
Manufacturing Errors ◽  
Stress Integration ◽  
Orthotropic Steel Decks

Fatigue cracks in orthotropic steel decks (OSDs) have been a serious problem of steel bridges for a long time. The structural stress approach is an important approach for fatigue life evaluation of welded structures. Firstly, two parameters and the mesh sensitivity of the stress-based integration equivalent structural stress approach (stress integration approach for short) are analyzed in this paper. Then, the applicability of the master S-N curve is verified based on experimental data of the deck-rib welding details in OSDs. Finally, the multi-scale finite element model (FEM) of Jiangyin Bridge is established, and the bridge fatigue life calculation steps based on the stress integration approach are given. The influence of the slope of the master S-N curve at high cycles on the bridge fatigue life is discussed. Further, the weld parameter influences on the bridge fatigue life are analyzed, as including the following: (1) The determination of the influence of the weld size changes caused by weld manufacturing errors on the bridge fatigue life; (2) the proposal of a new grinding treatment type, and the analysis of influence of the grinding radius on fatigue life; and (3) a comparison of the fatigue life of the deck-rib welding details under 80% partial penetration and 100% full penetration. The results show that the structural stress calculated by the stress integration approach does not change significantly with the parameters of the isolation body width w and the distance δ between the crack propagation surface and the reference surface. To simplify the calculation, δ is set as 0, and w can be set as the mesh size along the weld length direction. The mesh size of the stress integration approach is recommended as 0.25 times the deck thickness. The slope of the master S-N curve at high cycles significantly affects the bridge fatigue life, and a slope of 5 is reasonable. The weld parameter studies for the deck-rib welding details in the OSD of Jiangyin Bridge show that the change of weld size caused by manufacturing errors can obviously affect the bridge fatigue life, and the fatigue life of five different weld types varies from 51 years to 113 years. The new grinding treatment type, without weakening the deck, is beneficial to improving the bridge fatigue life. The fatigue life increases by approximately 5% with an increase of the grinding radius of 2 mm. The fatigue life of 80% partial penetration is slightly higher than that of 100% full penetration.

Outline of the Recent Consolidated Revision of EN13445-3, Clause 18 and Related Annexes: Detailed Assessment of Fatigue Life

2019 ◽  
Author(s):  
Jürgen Rudolph ◽  
Guy Baylac ◽  
Ralf Trieglaff ◽  
Rüdiger Gawlick ◽  
Michael Krämer ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Assessment Method ◽  
Structural Stress ◽  
Critical Plane ◽  
Fatigue Assessment ◽  
European Working ◽  
Critical Plane Approach ◽  
Detailed Assessment

Abstract The European Pressure Vessel Standard EN 13445 (harmonized Standard acc. to PED 2014/68/EU) provides in its Part 3 (Design) a simplified method for fatigue assessment (Clause 17) and a detailed method of fatigue assessment (Clause 18). While the new revision of Clause 17 has already been adopted, Clause 18 “Detailed Assessment of Fatigue Life” is now available as a consolidated revision in inquiry phase. This major and comprehensive revision has been developed within the framework of the European working group CEN/TC 54/WG 53 – Design methods and constitutes a crucial step towards a modern and user-friendly engineering fatigue assessment method. The overall structure and amendments of Clause 18 are to be presented. All these amendments aim at a significant increase in user friendliness and clear guidelines for application. The following items are to be mentioned in that context: • Fatigue assessment of welded components based on structural stress and structural hot-spot stress approaches, • Detailed guidelines for determining relevant stresses and stress ranges, • Cycle counting proposals in the context of the fatigue assessment method including a critical plane approach. The fatigue assessment of welded components is separated from the fatigue assessment of un-welded parts as it has already been done in previous versions with respective methodological differences. Stress analyses for clause 18 are usually based on detailed finite element analyses (FEA). As an essential amendment for the user, the determination of structural stress ranges for the fatigue assessment of welds is further detailed in a new appropriate annex. Different applicable methods for the determination of structural stresses are explained in connection with the requirements of the finite element models and analyses. The cycle counting issue is comprehensively treated in the context of different design and operation situations (design transients, operational stress-time-histories). The description is detailed towards a critical plane approach. Detailed proposals for implementation in an algorithmic programming framework are given making the described methods ready to use.

Improving Vehicle Body Structure NVH - An Experimental Approach

1993 ◽  
Author(s):  
David S. Snyder ◽  
Matthew P. Kriss ◽  
Robert S. Thomas
Keyword(s):  
Experimental Approach ◽  
Vehicle Body ◽  
Body Structure

Optimization of the Damping Seat’s Body Structure Based on the Task Space

2014 ◽  
Vol 1055 ◽  
pp. 143-146
Author(s):  
Hai Xian Zhao
Keyword(s):  
Natural Frequency ◽  
Suspension System ◽  
Vehicle Body ◽  
Optimized Design ◽  
Body Structure ◽  
Dimensional Problem ◽  
Task Space ◽  
System Research ◽  
Frequency Range ◽  
Seat Suspension

This paper is contrary to the seat multi-dimensional problem basing on task space. Using double triangle steward parallel mechanism as the main structure of the seat suspension, according to the sensitive frequency range and the natural frequency of vehicle body, we optimize the design of the suspension system. Research shows that the optimized design of the double triangle Stewart parallel suspension seat suspension system to ensure vertical, pitch, roll three of the more important natural frequency both directions away from the vehicle's natural frequency, but also avoid the human body sensitive frequency range.

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