Fatigue life assessment of welded joints in a crane boom using different structural stress approaches

This article presents a study of the fatigue strength of welded parts in a crane boom. First, a finite element analysis was carried out over the whole structure. Two critical welded zones were identified and a detailed analysis was carried on them, in the form of sub-models. Three different approaches for estimating the structural stress in welded zones, were presented and applied to each sub-model. Results were compared and discussed. The evaluation of fatigue resistance by the use of appropriate S-N curves for each method was also carried out and discussed. The use of these approaches on a complex industrial structure, and on tubular joints with hollow sections required to perform many adaptations and to solve several difficulties presented hereafter.

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Fatigue Strength Study on Radial Bogie Vice Frame Based on Finite Element Analysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.723.96 ◽

2015 ◽

Vol 723 ◽

pp. 96-99

Author(s):

Xiao Wei Wang ◽

Mao Xiang Lang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Life ◽

Fatigue Strength ◽

Structural Strength ◽

Simulation Software ◽

Experimental Result ◽

Element Analysis ◽

The Finite Element Analysis ◽

The Stability

The vice frame bears and transfers the forces and loads between the bogie and the vehicle body.The strength of the vice frame relates directly to the stability and smoothness of the vehicle. In this study, finite element analysis is utilized first to analyse the structural strength and fatigue life of the vice frame, and the recognize the weak parts of its structure in order to enhance its structural strength in the following design work.The finite element analysis is performed on a simulation software Ansys. Then an experiment is designed to test the fatigue strength of the vice frame. The experimental result indicates that the fatigue strength of the object corresponds to the standards and the finite element analysis has high feasibility in solving this kind of problem.

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Fatigue Life Assessment of a Ship Unloader Crane

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.945-949.1086 ◽

2014 ◽

Vol 945-949 ◽

pp. 1086-1089

Author(s):

Bin Xu ◽

Tao Zhang ◽

Feng Qi Wu ◽

Zhen Rong Yan

Keyword(s):

Finite Element ◽

Fatigue Life ◽

Residual Life ◽

Dynamic Properties ◽

Life Assessment ◽

Strength Analysis ◽

Dynamic Resistance ◽

Element Analysis ◽

Experimental Stress Analysis ◽

Fatigue Life Assessment

Ship unloader crane was widely used in transportation, and uploaded or unloaded cargoes from ships, which could influence efficiency and benefits of transportation greatly. In order to improve the reliability and safety, and decrease its risk in working flow, a method of fatigue life assessment was proposed in this paper. According to related standards and properties of risk, finite element method and experimental stress analysis were integrated to assess the working condition of a ship unloader crane. Finite element models of primary structures subjected to loads were built to achieve dynamic properties, which could supply a basic reference to experiment and guidance to locate the tested positions. Afterwards, wireless dynamic resistance strain-gauges were adopted to execute static and dynamic stress, and the tested results combined with finite element analysis were applied to strength analysis. Based on nominal stress and Miner principle, rainflow method was developed to fatigue life assessment of this ship unloader crane. The final results indicated that residual life of this crane was 4.67 years.

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Life Assessment of Turbine Components Through Experimental and Numerical Investigations

Journal of Pressure Vessel Technology ◽

10.1115/1.4007962 ◽

2013 ◽

Vol 135 (2) ◽

Cited By ~ 5

Author(s):

Dianyin Hu ◽

Rongqiao Wang ◽

Guicang Hou

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Life ◽

Life Prediction ◽

Life Assessment ◽

Element Analysis ◽

The Finite Element Analysis ◽

Creep Fatigue ◽

Turbine Component ◽

Good Agreement

A new lifetime criterion for withdrawal of turbine components from service is developed in this paper based on finite element (FE) analysis and experimental results. Finite element analysis is used to determine stresses in the turbine component during the imposed cyclic loads and analytically predict a fatigue life. Based on the finite element analysis, the critical section is then subjected to a creep-fatigue test, using three groups of full scale turbine components, attached to an actual turbine disc conducted at 750 °C. The experimental data and life prediction results were in good agreement. The creep-fatigue life of this type of turbine component at a 99.87% survival rate is 30 h.

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Shape Optimization of a Small Bus Steering Knuckle Considering a Fatigue Load

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.740.319 ◽

2013 ◽

Vol 740 ◽

pp. 319-322 ◽

Cited By ~ 1

Author(s):

Young Choon Lee ◽

Nam Jin Jeon ◽

Cheol Kim ◽

Seo Yeon Ahn ◽

Myung Jae Cho

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Life ◽

Fatigue Strength ◽

Shape Optimization ◽

Minimum Weight ◽

Cyclic Fatigue ◽

Fatigue Load ◽

Element Analysis ◽

Gradient Based

Finite element analysis was accomplished for a steering knuckle component of a small bus to see whether the static and fatigue strength requirements were satisfied or not. The knuckle was modeled with ANSYS 10-node quadratic elements. The cyclic fatigue load was applied and Soderberg criteria were applied to check the fatigue life. The knuckle structure has an infinite life (10-6 cycle) judging from the fatigue analyses. Shape optimization based on the gradient based method has been performed in order to find out the knuckle shape that has a minimum weight and satisfies the static and fatigue strength requirements. As a result of shape optimization, the weight of the steering knuckle was reduced 8%.

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Application of Two Methods for Notch Fatigue Life Prediction

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.488-489.654 ◽

2011 ◽

Vol 488-489 ◽

pp. 654-657

Author(s):

Radu Negru ◽

Liviu Marsavina ◽

Hannelore Filipescu ◽

Cristiana Caplescu

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Life ◽

Reduction Factor ◽

Volumetric Method ◽

Life Assessment ◽

Strength Reduction Factor ◽

Element Analysis ◽

Linear Elastic ◽

Notched Specimens

The aim of this paper is the application of two methods for notch fatigue life assessment, methods which are based on finite element analysis: the theory of critical distances and the volumetric method. Firstly, un-notched and notched specimens (for three different geometries) were tested in tension under constant-amplitude loading. The use of theory of critical distances (TCD) to predict the notch fatigue life involves the determination of the material characteristic length L based on experimental results obtained for the un-notched and one type of notched specimens. For the others notched geometries, based on linear-elastic finite element analysis, the fatigue strength is predicted using the TCD. In order to apply the volumetric method, elastic-plastic stress field around notches are considered and notch strength reduction factor are determined. Finally, the predictions of the two methods were compared with experimental fatigue data for notched specimens.

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Master S-N Curve-Based Fatigue Life Assessment of Steel Bridges Using Finite Element Model and Field Monitoring Data

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455419400133 ◽

2018 ◽

Vol 19 (01) ◽

pp. 1940013 ◽

Cited By ~ 1

Author(s):

X. W. Ye ◽

Y. H. Su ◽

T. Jin ◽

B. Chen ◽

J. P. Han

Keyword(s):

Finite Element ◽

Fatigue Life ◽

Welded Joint ◽

Element Model ◽

Field Monitoring ◽

Life Assessment ◽

Monitoring Data ◽

Steel Bridge ◽

Structural Stress ◽

Fatigue Life Assessment

The accuracy of fatigue life assessment for the welded joint in a steel bridge is largely dependent on an appropriate [Formula: see text]-[Formula: see text] curve. In this paper, a master [Formula: see text]-[Formula: see text] curve-based fatigue life assessment approach for the welded joint with an open-rib in orthotropic steel bridge deck is proposed based on the finite element model (FEM) and field monitoring data from structural health monitoring (SHM) system. The case studies on fatigue life assessment by use of finite element analysis (FEA) for constant-amplitude cyclic loading mode and field monitoring data under variable-amplitude cyclic loading mode are addressed. In the case of FEA, the distribution of structural stress at fatigue-prone weld toe is achieved using 4-node shell element model and then transformed into equivalent structural stress by fracture mechanics theory. The fatigue life of the welded joint is estimated with a single master [Formula: see text]-[Formula: see text] curve in the form of equivalent structural stress range versus the cycles to failure. In the case of monitoring data-based fatigue life assessment, the daily history of structural stress at diaphragm to U-rib is derived from the raw strain data measured by the instrumented fiber Bragg grating (FBG) sensors and transformed into equivalent structural stress. The fatigue life of the investigated welded joint is calculated by cyclic counting method and Palmgren–Miner linear damage cumulative rule. The master [Formula: see text]-[Formula: see text] curve method provides an effective fatigue life assessment process, especially when the nominal stress is hard to be defined. A single master [Formula: see text]-[Formula: see text] curve will facilitate to solve the difficulty in choosing a proper [Formula: see text]-[Formula: see text] curve which is required in the traditional fatigue life assessment methods.

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Structural Stress Correction Methods for Linear Elastic Finite Element Analysis of Spot Welded Joints

Volume 9: Mechanics of Solids, Structures and Fluids; NDE, Diagnosis, and Prognosis ◽

10.1115/imece2016-66884 ◽

2016 ◽

Cited By ~ 1

Author(s):

Hong-Tae Kang ◽

Xiao Wu

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Life ◽

Welded Joints ◽

Life Prediction ◽

Structural Stress ◽

Test Results ◽

Element Analysis ◽

Linear Elastic ◽

Spot Welded

Structural stress concepts are widely used in fatigue life prediction of spot welds and seam welds in vehicle structures. For fatigue life prediction of welded joints based on the structural stress methods, it is necessary to obtain applied force ranges versus fatigue life of the welded specimens. Then, the force ranges versus fatigue life information is converted to structural stress ranges versus fatigue life (S-N) of the joints. The structural stress ranges versus the fatigue life curve of the welded specimens becomes the material fatigue property of the welded joints to predict fatigue life of joints in vehicle structures. While converting the applied load ranges to the structural stress ranges, linear elastic finite element analysis (FEA) is used. Therefore, the applied load ranges are considered as the responses of linear elastic deformation even though the load ranges consist of the linear elastic deformation and plastic deformation. As results the structural stress ranges of the welded joints are reduced in S-N curve. This study introduces simple techniques for spot welded joints to include the plastic deformation effect on the structural stress calculation without performing elastic-plastic finite element analysis. Fatigue test results of spot welded joints for lap-shear and coach peel specimens of advanced high strength steels (AHSS) and mild steels were used. The corrected structural stress methods showed better correlation with the test results.

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