Finite Element Analysis of a Pressure Vessel Subjected to an Internal Blast Load

Author(s):  
I. Barsoum ◽  
L. Sadiq

The objective of the current work is to model a stainless steel SA 316L autoclave explosion and rupture that occurred during a research laboratory experiment designed to study the thermal decomposition of ammonium tetrathiomolybdate in the presence of dimethyl sulfoxide (DSMO) in an autoclave. The explosion was believed to have occurred because DMSO was used in excess in the experiment and heated beyond its decomposition temperature. The aim of the current study is to investigate the effect of internal blast load on a pressure vessel made of stainless steel AISI 316L through finite element analysis. Numerical simulation using FEA is performed to better understand the cause of failure of the pressure vessel. The finite element model predicts very well the structural response and subsequent failure of the actual incident and the results reveal that the root cause to failure was an internal blast load, which arose from the decomposition of DMSO at high temperature.

2021 ◽  
Vol 2 (3) ◽  
pp. 1-7
Author(s):  
Tirimisiyu Abiodun Buari

This research investigated the comparative structural response of a straight and curved continuous bridge deck subjected to realistic working loads. The study involved examining the variance in analysis results obtained while utilizing the grillage and finite element methods for an idealized bridge deck. The combined impact of continuity at the intermediate support and the curvature on the overall structure was examined. The idealized case study is a 45m two-span continuous bridge deck with a 22.5m straight span and an equivalent 22.5m curved span with a centerline radius of approximately 14.32m. The bridge deck was designed for design dead load and 45 units of HB load, these loads were computed based on recommendations given in BS 5400-2:2006 and BD 37/01-1:2001[1,2]. For the Grillage Analysis Sap2000 version 22 software was utilized while CSI Bridge version 21 was used to simulate the Finite Element model. The findings from the study revealed that the results obtained from the grillage analysis method were more conservative with respect to midspan sagging moments and support shear force. However, the finite element analysis result was more conservative for support hogging moments, deflection and torsional moments. It was concluded that finite element analysis result values differed from the grillage analysis, but the values were close enough with the disparity not calling for serious concerns.


Author(s):  
R. Dennis ◽  
N. Leggatt ◽  
C. T. Watson ◽  
E. Kingston ◽  
D. J. Smith

A programme of work was undertaken to gain an understanding of the residual stress levels in the tube penetration J-groove welds in a hemispherical head of a large stainless steel clad ferritic pressure vessel. This second part of a two-part paper describes the finite element analysis that was carried out to model an off-centre outer tube to vessel head weld. A 3D finite element residual stress model was developed. The complex bead deposition sequence of the actual weld was simulated by a bead lumping approach using 9 passes. The results from the finite element analyses were compared with both surface and through thickness stress measurements. These measurements were taken on a mock weld that was representative of the actual component. The surface measurements were taken by using an incremental centre hole drilling technique. The through thickness values were obtained from deep hole drilling measurements at three positions around the circumference of the weld. For this off-centre penetration the cladding process was not modelled nor was clad applied to the test mock-up. The finite element results and the measured values showed similar trends in the variation of stress around the circumference of the weld. A poor correlation between measurements and analytical results was obtained at the lower hillside position. A major reason for the discrepancy is believed to be that the bead lumping approach that was used in the finite element model was not a sufficiently refined representation of the actual weld bead deposition sequence. Note however that one of the aims of this finite element analysis was to quantify the variations between the centre tube presented in the first part of this paper and the off centre tube presented here. In this regard the finite element model and measurements compared well. The finite element model was also used to carry out two sensitivity studies that investigated the effects upon residual stress of tube geometry and material properties. For the case where a nozzle tube was extended significantly below the vessel head inner surface the results showed the stresses to be significantly higher than the baseline case.


2019 ◽  
Vol 10 (3) ◽  
pp. 359-379
Author(s):  
Lekhani Gaur ◽  
Tanusree Chakraborty ◽  
Ashish K Darpe ◽  
Vasant Matsagar

The study presented herein includes finite element analysis of a box type structure subjected to blast loading using the coupled Eulerian-Lagrangian methodology to investigate the structural response. A comparative assessment of structural response observed from coupled Eulerian-Lagrangian and Unified Facility Criteria guidelines is presented. Furthermore, the effect of the structural parameters on reflected overpressure for different angle of incidence has been investigated and compared with that given in the Unified Facility Criteria. It is observed that the structural parameters significantly affect the reflected overpressure. The Unified Facility Criteria overestimates the response of structure in a certain region of angle of incidence while it underestimates the reflected pressure in the rest region of the angle of incidence.


Author(s):  
Dennis Lam ◽  
Jie Yang ◽  
Xianghe Dai

In recent years, a new low nickel content stainless steel (EN 1.4162) commonly referred as ‘lean duplex stainless steel’ has been developed, which has over two times the tensile strength of the more familiar austenitic stainless steel but at approximately half the cost. This paper presents the finite element analysis of concrete filled lean duplex stainless steel columns subjected to concentric axial compression. To predict the performance of this form of concrete filled composite columns, a finite element model was developed and finite element analyses were conducted. The finite element model was validated through comparisons of the results obtained from the experimental study. A parametric study was conducted to examine the effect of various parameters such as section size, wall thickness, infill concrete strength, etc. on the overall behaviour and compressive resistance of this form of composite columns. Through both experimental and numerical studies, the merits of using lean duplex stainless steel hollow sections in concrete filled composite columns are highlighted. In addition, a new formula based on the Eurocode 4 is proposed to predict the cross-section capacity of the concrete filled lean duplex stainless steel composite columns subjected to axial compression.


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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