FEA shell element model for enhanced structural stress analysis of seam welds

The mussel trap is an important component used in nuclear power plant (NPP). The component belongs to RCC-P nuclear safety class 3, code and class RCC-M3, seismic category 1F and Q.A category Q2. The mussel trap is made up of screen, half-sphere, main flanges, nozzles, rotors, bolts, motor, supports and so on. The loads requirements in design conditions contain both internal loads and external loads. The loads have dead weight, pressure, nozzles loads and seismic loads. In this paper, the finite element model of the mussel trap is built with shell element using the structural analysis software-ANSYS. The stress analysis is based on linear elastic static analysis. The subspace iteration method is used for the modal analysis of the mussel trap. The static analysis is used for the mussel trap under deadweight, pressure and nozzle loads. At last, an evaluation of all loads combinations stresses against the respective stress limit for plate- and shell-type components and linear type systems is done according to the requirements of relative criteria specified in RCC-M. The evaluation result demonstrates that all loads combinations stresses of the mussel trap structure meet the requirements of RCC-M.

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Numerical aspects for efficient welding computational mechanics

Thermal Science ◽

10.2298/tsci130227180a ◽

2014 ◽

Vol 18 (suppl.1) ◽

pp. 139-148

Author(s):

Tarek Aburuga ◽

Aleksandar Sedmak ◽

Zoran Radakovic

Keyword(s):

Residual Stresses ◽

Three Dimensional ◽

Shell Element ◽

Element Model ◽

Mechanical Analysis ◽

Tensile Test Specimen ◽

Integrity Assessment ◽

Mass Scaling ◽

Three Dimensional Models ◽

Thermal Mechanical Analysis

The effect of the residual stresses and strains is one of the most important parameter in the structure integrity assessment. A finite element model is constructed in order to simulate the multi passes mismatched submerged arc welding SAW which used in the welded tensile test specimen. Sequentially coupled thermal mechanical analysis is done by using ABAQUS software for calculating the residual stresses and distortion due to welding. In this work, three main issues were studied in order to reduce the time consuming during welding simulation which is the major problem in the computational welding mechanics (CWM). The first issue is dimensionality of the problem. Both two- and three-dimensional models are constructed for the same analysis type, shell element for two dimension simulation shows good performance comparing with brick element. The conventional method to calculate residual stress is by using implicit scheme that because of the welding and cooling time is relatively high. In this work, the author shows that it could use the explicit scheme with the mass scaling technique, and time consuming during the analysis will be reduced very efficiently. By using this new technique, it will be possible to simulate relatively large three dimensional structures.

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Contrastive Study on Finite Element Models of High-Strength Pipelines Crossing Active Faults

Materials Science Forum ◽

10.4028/www.scientific.net/msf.850.957 ◽

2016 ◽

Vol 850 ◽

pp. 957-964

Author(s):

Wei Zheng ◽

Hong Zhang ◽

Xiao Ben Liu ◽

Le Cai Liang ◽

Yin Shan Han

Keyword(s):

Finite Element ◽

Design Method ◽

Active Faults ◽

Shell Element ◽

High Strength ◽

Element Model ◽

Beam Element ◽

Finite Element Models ◽

Fixed Boundary ◽

Equivalent Boundary

There is a potential for major damage to the pipelines crossing faults, therefore the strain-based design method is essential for the design of buried pipelines. Finite element models based on soil springs which are able to accurately predict pipelines’ responses to such faulting are recommended by some international guidelines. In this paper, a comparative analysis was carried out among four widely used models (beam element model; shell element model with fixed boundary; shell element model with beam coupled; shell element model with equivalent boundary) in two aspects: differences of results and the efficiency of calculation. The results show that the maximum and minimum strains of models coincided with each other under allowable strain and the calculation efficiency of beam element model was the highest. Besides, the shell element model with beam coupled or equivalent boundary provided the reasonable results and the calculation efficiency of them were higher than the one with fixed boundary. In addition, shell element model with beam coupled had a broader applicability.

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Strength-based design of a sunflower stalk cutter machine design using finite element analysis and experimental validation

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211059741 ◽

2021 ◽

pp. 095440622110597

Author(s):

Gürkan İrsel

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Stress Analysis ◽

Strain Gage ◽

Experimental Validation ◽

Experimental Studies ◽

Fatigue Analysis ◽

Structural Stress ◽

Element Analysis ◽

Strength Based

In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.

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Exact geometry solid-shell element based on a sampling surfaces technique for 3D stress analysis of doubly-curved composite shells

Curved and Layered Structures ◽

10.1515/cls-2016-0001 ◽

2015 ◽

Vol 3 (1) ◽

Cited By ~ 3

Author(s):

G. M. Kulikov ◽

A. A. Mamontov ◽

S. V. Plotnikova ◽

S. A. Mamontov

Keyword(s):

Stress Analysis ◽

Numerical Solutions ◽

Variational Equation ◽

Shell Element ◽

Middle Surface ◽

Superior Performance ◽

Lagrange Polynomials ◽

Shell Formulation ◽

Coarse Meshes ◽

Doubly Curved

AbstractA hybrid-mixed ANS four-node shell element by using the sampling surfaces (SaS) technique is developed. The SaS formulation is based on choosing inside the nth layer In not equally spaced SaS parallel to the middle surface of the shell in order to introduce the displacements of these surfaces as basic shell variables. Such choice of unknowns with the consequent use of Lagrange polynomials of degree In − 1 in the thickness direction for each layer permits the presentation of the layered shell formulation in a very compact form. The SaS are located inside each layer at Chebyshev polynomial nodes that allows one to minimize uniformly the error due to the Lagrange interpolation. To implement the efficient analytical integration throughout the element, the enhanced ANS method is employed. The proposed hybrid-mixed four-node shell element is based on the Hu-Washizu variational equation and exhibits a superior performance in the case of coarse meshes. It could be useful for the 3D stress analysis of thick and thin doubly-curved shells since the SaS formulation gives the possibility to obtain numerical solutions with a prescribed accuracy, which asymptotically approach the exact solutions of elasticity as the number of SaS tends to infinity.

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