Case Study to Evaluate Stresses in Welded Endplates in Structural Steel

2021 ◽  
Author(s):  
Kshitij P. Gawande ◽  
Alex Mayes ◽  
Raju Subedi

Abstract Endplates are widely used in the industry to attach supplementary steel structures to main building frames. These endplates can be attached to the building steel using a bolted connection or a welded connection. Industry often favors bolted connections due to ease of installation and availability of qualification methods per AISC 360 Design Guides. However, there are some applications where a welded connection is preferable, such as, cases requiring reduction of number of parts supplied or applications with higher chance of vibration causing loosening of bolts. The present case study discusses evaluation of stresses in welded endplates due to forces and moments from the attaching supplementary steel members. The study considers various welded connection scenarios including an endplate welded on two opposite sides and an endplate welded on all four sides. The stress distribution in the plate is studied using finite element analysis with wide flange and tube steel members attaching to it. ANSYS mechanical is used to perform the finite element analysis. Multiple combinations of plate sizes, weld patterns, and attaching member sizes are analyzed to provide a well-rounded solution. An analytical model is developed for the stress evaluation as well and the results are compared with the finite element model. The study is intended to provide an efficient methodology for plate evaluation and qualification.

Author(s):  
Alex Berry ◽  
Warren Brown ◽  
Antonio Seijas ◽  
Sarah Cook

Abstract Coke drums are subjected to severe thermal cycling with the skirt to shell connection weld being vulnerable to fatigue cracking. It is essential this connection is well designed to ensure a long life before repairs are inevitably required. Much has been written on coke drum skirt design with the aim of reducing the thermal stresses and strains encountered at the skirt connection weld, some designs have removed the weld completely allowing the drum to sit in an “egg-in-cup” arrangement. This paper includes a short literature review discussing Coke drum skirt designs and explains skirt behaviour during the drum cycle that results in eventual skirt cracking. A case study is reviewed in detail for a new pair of coke drums, where the predicted fatigue life of the chosen welded connection is assessed using axisymmetric, quarter symmetry and half symmetry finite element analysis supported by thermocouple data. The optimised design focuses on a conventional tangential design where the effects of the essential variables such as skirt thickness, skirt connection location, skirt-to head-gap and slot design (length, location & spacing) have been modelled and optimised to obtain a skirt design that produces the longest fatigue life for the intended duty cycle. Coke drum skirts must be installed onto the shell to exacting tolerances during manufacture to ensure concentricity and minimal gap between the skirt and shell. A brief overview of how this is achieved will be presented.


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.


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.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.


2011 ◽  
Vol 346 ◽  
pp. 379-384
Author(s):  
Shu Bo Xu ◽  
Yang Xi ◽  
Cai Nian Jing ◽  
Ke Ke Sun

The use of finite element theory and modal analysis theory, the structure of the machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important. Selected for three-dimensional CAD modeling software-UG NX4.0 and finite element analysis software-ANSYS to set up the structure of the beam finite element model, and then post on the overall structure of the static and dynamic characteristic analysis, on the basis of optimized static and dynamic performance is more superior double wall structure of the beam. And by changing the wall thickness and the thickness of the inner wall, as well as the reinforcement plate thickness overall sensitivity analysis shows that changes in these three parameters on the dynamic characteristics of post impact. Application of topology optimization methods, determine the optimal structure of the beam ultimately.


Author(s):  
Luiz T. Souza ◽  
David W. Murray

The paper presents results for finite element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure and monotonically increasing curvatures. Recommendations for the ‘best’ type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.


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