A Simplified Procedure for Global Hull Strength Analysis of Classic Spars

2014 ◽  
Author(s):  
Xiaoqing Teng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Frequency Response ◽  
Shear Force ◽  
Low Frequency ◽  
Bending Moment ◽  
Wave Frequency ◽  
Structural Components ◽  
Element Analysis ◽  
Wave Induced

Primary structural components of a spar hull are designed to resist lateral hydrodynamic and hydrostatic pressure and global loads. The scantlings of each primary component are usually determined based on the largest pressure it may encounter in various phases such as wet-tow, upending, and in-place operational conditions. The effect of global bending moment and shear force on the spar hull is often evaluated much later via laborious finite element analysis. This paper proposes a simple analytical tool for quickly assessing global hull strength of classic spars in the in-place condition. A spar platform undergoes steady, low-frequency, and wave-frequency motion of comparable magnitude at the same time in a storm event. The present approach separates the wave-frequency component from the steady and low-frequency response. A closed-form solution is developed for wave-induced motion and loads by taking advantage of the simple cylindrical shape of classic spar hulls. The theoretical solution is verified by comparing to numerical WAMIT results. The low-frequency response is approximated as one part of the steady response, since its dynamic effect is weak. The steady structural response is mainly a function of the heel angle. It is demonstrated that local effect of wind pressure and current load is not significant. The total response, as a summation of the wave-induced loads and the steady solution, is represented by global bending moment and shear force envelopes along the spar hull for a given sea state. Global bending and shear stresses of primary structural components can be further calculated and checked against code requirements. This procedure has been implemented through Matlab scripts. A comparison with global finite element analysis for a classic spar is made showing very good agreement. The present simple procedure allows us to evaluate primary structural components of a spar hull without resorting to expensive finite element modeling. It can help the scantling design by providing the global load. The approach can also be used to identify critical environmental conditions and structural components for detailed finite element analysis.

scholarly journals Soil Interaction of Building Frame Resting on Clayey Soil: Effect of Change of Footing Size

2019 ◽  
Vol 8 (2) ◽  
pp. 4874-4879
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Force ◽  
Clayey Soil ◽  
Bending Moment ◽  
Design Parameters ◽  
Element Analysis ◽  
Building Frame ◽  
Super Structure ◽  
Percentage Difference

In every structure, the super structure and the foundation executed on soil, represent an entire structural system. The analysis of a framed structure while not modeling its foundation system and its rigidity could mislead the axial forces, moments due to bending and due to settlement. It is, thus necessary to hold out the analysis considering the type of soil, foundation and above the sub structure i.e. (super structure). Hence the analysis of the single bay single storied building frame resting on soil (Clayey Soil) is taken for present study. The analysis is carried out using “ANSYS 16.0”. In this paper the effect of soil interaction on building frame design parameters as change of modulus of sub-grade reaction from 0.010 to 0.050 N/mm3 .Shear force, Bending moment and settlements have been studied for different footing sizes of 1mx1m to 4.5mx4.5m the effect of SSI is quantified using finite element analysis. The following conclusions have been drawn from the study, the shear force and axial force value in the beam and column is constant from finite element analysis are not having considerable difference. The analysis is predicting that percentage difference in bending moment in beam, column and footings are at lower EFS value i.e 0.010N/mm3 at lower footing size 1mX1m is greater than when compared to higher EFS value i.e 0.050N/mm3 at higher footing size 4.5mX4.5m which considers soil interaction. But in case of the footings they undergo some settlement the percentage difference of settlement is 14.41% and 6.72% at lower EFS value i.e 0.010N/mm3 at lower footing size 1mx1m when compared to higher EFS value i.e 0.050N/mm3 at higher footing size 4.5mx4.5m respectively, which considers soil interaction.

The Limit Load Interactions of the Brazed Aluminum Plate-Fin Heat Exchanger Header Under Combined Piping Loads

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Wei Wang ◽  
Liang Chen ◽  
Caidong Guo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Exchanger ◽  
Axial Force ◽  
Shear Force ◽  
Bending Moment ◽  
Limit Load ◽  
Force Component ◽  
Element Analysis ◽  
Interaction Curves

In order to investigate the strength design problem of the brazed aluminum plate-fin heat exchanger header under complex external piping loads, the limit load interactions of the header under combined piping loads are studied in this paper. To establish the limit piping load interaction curves, nonlinear finite element analysis assuming the elastic perfectly plastic material model is performed by using the commercial finite element analysis software ANSYS and multiple piping load combinations, which are the combination of orthogonal bending moment components, torque component-shear force component, bending moment component-axial force component, compound bending moment-axial force component, and torque component-compound shear force, of the header with six opening ratios ranging from 0.5 to 1 are explored. The results of the interaction diagrams show that the feasible combined piping load zone of the header derived from the interaction curves can be simplified as a triangular zone determined by the individual limit piping load components safely and the simplified feasible zone is suggested to be used for establishing a simplified safety assessment method for the header under combined piping loads.

scholarly journals A Review on Numerical Analysis of RC Flat Slabs Exposed to Fire

2020 ◽  
Vol 27 (1) ◽  
pp. 1-5
Author(s):  
Hanadi Naji ◽  
Nibras Khalid ◽  
Mutaz Medhlom
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Bending Moment ◽  
Mechanical And Thermal Properties ◽  
Vertical Deflection ◽  
Element Analysis ◽  
Flat Slabs ◽  
Numerical Studies ◽  
The Finite Element Analysis

This paper aims at presenting and discussing the numerical studies performed to estimate the mechanical and thermal behavior of RC flat slabs at elevated temperature and fire. The numerical analysis is carried out using finite element programs by developing models to simulate the performance of the buildings subjected to fire. The mechanical and thermal properties of the materials obtained from the experimental work are involved in the modeling that the outcomes will be more realistic. Many parameters related to fire resistance of the flat slabs have been studied and the finite element analysis results reveal that the width and thickness of the slab, the temperature gradient, the fire direction, the exposure duration and the thermal restraint are important factors that influence the vertical deflection, bending moment and force membrane of the flat slabs exposed to fire. However, the validation of the models is verified by comparing their results to the available experimental date. The finite element modeling contributes in saving cost and time consumed by experiments.

Dynamic Interaction of High-Voltage Power Transformer Bushings, Turrets, and Tanks

2018 ◽  
Vol 34 (1) ◽  
pp. 397-421 ◽  
Author(s):  
Guo-Liang Ma ◽  
Qiang Xie ◽  
Andrew Whittaker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Voltage ◽  
Power Transformer ◽  
Bending Moment ◽  
Dynamic Interaction ◽  
Electrical Performance ◽  
Element Analysis ◽  
Ground Shaking ◽  
Input Motion

High-voltage (HV) bushings are attached to a power transformer tank either directly or indirectly via turrets. Turrets are used to achieve electrical performance requirements, but their potential impact on the seismic performance of the supported bushings has not been considered. Earthquake simulator testing and finite-element analysis were used to quantify the amplification of ground shaking through tanks (220- and 500-kV) and turrets to the points of attachment of roof- and sidewall-supported bushings. Substantial amplification of motion was seen in both physical experiments and numerical simulations. Sample bracing schemes external to the transformer tank were investigated to potentially reduce the motions experienced by the bushings. Bushing tip displacements were reduced in all stiffening cases studied, but the outcomes for bending moment at the bushing-turret connection were mixed, with no change in some cases and significant reductions in others. The physical and numerical studies described in this paper make clear the importance of dynamic interaction of bushings, turrets, and the power transformer tank. The methods currently used to address the amplification of input motion from the base of a tank to the points of attachment of its bushing are inadequate. The seismic design of HV power transformer tanks and turrets should be supported by finite-element analysis of validated models to avoid dynamic interaction in the bushing-turret-tank system, to minimize seismic demand on the transformer bushings, and to minimize the risk of substation damage in earthquakes.

Capacity Analysis of PE Pipeline With Non-Planar Defect

2013 ◽  
Author(s):  
Weijie Jiang ◽  
Jianping Zhao ◽  
Dingyue Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Constitutive Model ◽  
Mechanical Performance ◽  
Orthogonal Design ◽  
Bending Moment ◽  
Limit Load ◽  
Capacity Analysis ◽  
Element Analysis ◽  
Load Factors

A tensile test of buried PE pipe is designed to test the mechanical performance. Then the constitutive model for the PE pipe can be established. The limit load of the PE pipe with local thinning defect can be studied with the method of combining the orthogonal design of experiment and finite element analysis. Then the factors of local thinning defect pipe limit load factors can be analyzed. The results show that the depth of the defect has a great effect on the limit load (internal pressure and bending moment) of PE pipe. The effects that the axial length of the defect and the circumferential length of the defect have on the limit load are not significant.

Finite Element Analysis of Embedded Parts with Big-Diameter Reinforcing Bar under Shear Force

2010 ◽  
Vol 452-453 ◽  
pp. 509-512
Author(s):  
Yao Guo Zhu ◽  
Qing Xiang Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Force ◽  
Three Dimensional ◽  
Interaction Force ◽  
Internal Force ◽  
Shear Capacity ◽  
System Response ◽  
Element Analysis ◽  
Reinforcing Bar

Nowadays embedded parts which connect steel members with concrete structures have frequently emerged in civil engineering; however the existing design code for embedded parts cannot satisfy the increasing demand of engineering as it was derived from limited experiments. In the paper, a finite element study on embedded parts with big-diameter reinforcing bars under shear force is conducted. The aim of the study was to fully investigate the mechanical performances of embedded parts under shear force using a three-dimensional finite element analysis with the help of a commercial software ANSYS. Cross-section internal force of anchor bar, embedded part deformation, interaction force between anchor bar and concrete, and friction force were investigated in order to well know the system response. The results show that the shear capacity of embedded part obtained from finite element analysis is conservative.

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