Reduction in Inspection Costs for Dynamic Sensitive Steel Structures by Modal Based Fatigue Monitoring

Author(s):  
Henrik Hjelm ◽  
John D. So̸rensen ◽  
Rune Brincker ◽  
Kasper Munch ◽  
Jesper Graugaard-Jensen

In risk based inspection planning the number of planned inspections directly depends on the uncertainty on the load history. In this paper it is shown how this uncertainty can be reduced by modal based fatigue monitoring. The technique is based on continuously measuring of the accelerations in few points of the structure. The accelerations are integrated to obtain the displacement and a modal decomposition of the obtained displacements is performed. The relation between the modal coordinates and the stress history in an arbitrary point of the structure is established by a calibrated finite element model. The technique has been applied on a wind loaded lattice pylon structure and compared with strain gauges measurements, showing that the uncertainty on the presented technique is quite small. It is shown that if the technique is applied to an offshore steel structure, then the number of required inspections may be reduced with more than 50%.

10.14311/1083 ◽  
2009 ◽  
Vol 49 (1) ◽  
Author(s):  
C. Crosti

This paper focuses on the structural analysis of a steel structure under fire loading. In this framework, the objective is to highlight the importance of the right choice of analyses to develop, and of the finite element codes able to model the resistance and stiffness reduction due to the temperature increase. In addition, the evaluation of the structural collapse under fire load of a real building is considered, paying attention to the global behavior of the structure itself. 


2014 ◽  
Vol 1049-1050 ◽  
pp. 378-382
Author(s):  
Ju Bing Zhang ◽  
Shao Xia Zhang ◽  
Ying Zou

In recent years, the problem of the human-induced bridge vibration has attracted more and more concerns. In this paper , a steel structure footbridge named Shuang'an East in Beijing was taken as the example to collect the whole bridge vibration data and build the finite element model with the finite element software. In addition, this research changes the limitation of considering the pedestrian load as a whole with a traffic flow simulation software, which is based on social force model, applying to reflect the pedestrians' locations during walking. Comparing the simulation data with the the measured data, the vibration serviceability of footbridge will decrease with the increasing of the number of the pedestrians. The analysis results will provide reference for the dynamic characteristic of similar structures.


2015 ◽  
Vol 1119 ◽  
pp. 828-832
Author(s):  
K. Vadivuchezhian ◽  
K. Subrahmanya ◽  
N. Chockappan

Metal foil strain gauges are most widely used for the stress analysis in engineering structures. Typical strain gauge system includes strain sensitive grid, carrier material, and adhesive layer. Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. In the present work, a Finite Element Model is developed in order to study the effect of both adhesive layer and carrier thickness on strain measurements while using strain gauges. To understand the behavior of the adhesive material, mechanical characterization is done on bulk adhesive specimen. Finite Element Analysis (FEA) is carried out with different materials namely epoxy and polyurethane. Initially a single element foil loop is considered for the analysis and further this is extended to metal foil strain gauge with nine end-loops. Finally, the strain variation through thickness of adhesive layer, carrier and strain sensitive grid is obtained from FEA. The results thus obtained are compared with analytical results from Basic Strength of Materials approach.


2013 ◽  
Vol 753-755 ◽  
pp. 1196-1200
Author(s):  
Lu Yu Huang ◽  
Yang Gao ◽  
Xia Cao

Based on the construction features of the steel structures of a type of electrical dust precipitator, a finite element model is established with large-scale finite element analysis software ANSYS, and the structure stress and displacement of the model under all sorts of loads are analyzed with the frontal solution method. The results indicate that analysis is relatively accurate, the finite element model and the analysis method is appropriate. The result can be further used for optimization design of the electrical precipitator steel structures.


2013 ◽  
Vol 690-693 ◽  
pp. 1933-1939
Author(s):  
Peng Shang ◽  
Wei Zhou ◽  
Chun Xia Li ◽  
Yu Ming Guan

Bucket wheel stacker-reclaimer is kind of a typical multi-rigid-body system. Its main steel structure consists of bucket wheel, forearm frame, column tower, balance frame and pull rod, etc. All components connected with each other basically by welding. And the integral structure can realize whole luffing motion and turning motion. Reclaiming arm, central bracket and pitch steel structure of counterweight arm are the structure of its core. This paper use ANSYS to create the simplified finite element model of the steel structure and analyze the distribution of loads in all types of conditions. Loading solving, then cloud picture of displacement and that of stress of the overall luffing mechanism was concluded, so as to check the carrying capacity and strength of the structure.


2020 ◽  
Vol 47 (10) ◽  
pp. 1175-1187
Author(s):  
G. Aruna ◽  
V. Karthika ◽  
S. Sukumar

This paper describes a finite element analysis (FEA) and design of cold-formed steel built-up closed sections with intermediate stiffeners in the flange and web under axial compression. A finite element model (FEM) was developed and validated using the available experimental results. The validated FEM can be used for further parametric study on strength of built-up closed columns. The results obtained from the parametric study are compared with the current direct strength method (DSM) in the North American specification of cold-formed steel structures for those specimens that failed by only local, distortional, and flexural buckling. It is shown that the current DSM is not quite suitable for the design of cold-formed steel built-up closed columns. Therefore, the improved design equations are proposed by modifying the current design equations used in the DSM for flexural, local, and distortional buckling. The reliability of current DSM and proposed DSM was assessed by reliability analysis.


2020 ◽  
Vol 23 (12) ◽  
pp. 2694-2708
Author(s):  
Shan Chang ◽  
Ming Yang ◽  
Linjie Tian ◽  
Pengfei Yuan

Due to the improvement of steel properties, many steel structures with attractive appearance emerge unceasingly. In this article, a new structure of steel octagon-web beam which has the similar appearance with honeycomb beam was presented. The mechanical characteristics of steel octagon-web beam under bending loads were analyzed theoretically. Based on the Vierendeel truss theory in deflection calculation of honeycomb beam, the deflection calculation method of steel octagon-web beam which was validated by finite element method was studied. Two parameters affecting deflection of steel octagon-web beam, such as opening type and expansion ratio, were analyzed. A scale model of steel octagon-web beam was manufactured in order to study bending behavior of the structure. The failure patterns of test specimen under four-point bending test are the buckling of deck and web. A nonlinear finite element model of test specimen whose results were compared with test was established by software ABAQUS 2017. The stresses of slabs under ultimate load have reached yield stress, which shows steel octagon-web beam has good flexural performance.


2013 ◽  
Vol 690-693 ◽  
pp. 3121-3124 ◽  
Author(s):  
Peng Shang ◽  
Yao Zong Hu ◽  
Li Hu He ◽  
Yu Ming Guan

The vibration mode of main steel structure of bucket wheel stacker reclaimer is complex and changeable, so its modal analysis is necessary. In this paper, the main steel structure of bucket wheel stacker reclaimer was integrally designed and its main parameters were determined. then the finite element model of the main steel structure of the bucket wheel stacker reclaimer was established and the modal analysis was simulated, finally the results of its inherent frequency were calculated by FEA method.


1989 ◽  
Vol 16 (2) ◽  
pp. 172-181 ◽  
Author(s):  
G. Gendron ◽  
D. Beaulieu ◽  
G. Dhatt

A finite element model which takes account of plasticity and contact for the behavior of bolted steel connections is presented in this study. The mathematical formulation is first presented, followed by the analysis of two bolted connections and a presentation of the results. Future developments and possible applications are finally described. Key words: steel structures, bolted connections, mathematical model, finite element, nonlinear analysis, plasticity.


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