Study on Production-Oriented Design for the Capesize Bulk Carrier: Using Transverse Reinforced Double-Bottom Pipe Duct

2006 ◽  
Vol 22 (01) ◽  
pp. 15-20
Author(s):  
Shou-Hsiung (Vincent) Hsu ◽  
Jong-Shyong Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Vertical Deflection ◽  
Bulk Carrier ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Bulk Carriers ◽  
Reducing Costs ◽  
Steel Weight

Cutting total man-hours is one of the most effective ways of reducing costs in a shipyard and, in general, designing structures with fewer pieces will achieve the goal of reducing man-hours. The Capesize bulk carrier, due to requirements for access, ballast capacity, and double-bottom height, always has a pipe duct in the center part of the double bottom. Comparison between two existing Capesize bulk carriers reveals that one may eliminate more than 1,800 structural pieces (about 2.6% of the total number of ship pieces) if the conventional longitudinal reinforced pipe duct is replaced by a transverse reinforced one. Further, from the finite element analysis (FEA) results using the SafeHull computer package of the American Bureau of Shipping (ABS), it has been found that the vertical deflection and stress concentration of the double bottom are improved and some of the thicker plates can be removed if the transverse reinforced pipe duct is used. Therefore, the overall steel weight for the Capesize bulk carrier using the transverse reinforced pipe duct was found to be less than that using the longitudinal reinforced pipe duct.

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.

Determination of CANDU End Fitting Jacking Limits Using Elastic-Plastic Finite Element Analysis

2010 ◽  
Author(s):  
Bing Li ◽  
Dave McNeish ◽  
Seyun Eom ◽  
D. K. Vijay ◽  
Si-tsai Lin ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
The West ◽  
Reactor Unit ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Division 1 ◽  
The Finite Element Analysis ◽  
Abaqus Model

In one CANDU reactor unit in Ontario, the west end fitting is designed to connect to the end shield via a stop collar. The outboard end of the stop collar is welded to an attachment ring which shrink-fits on the end fitting body. The east side end fitting is supported by inboard and outboard journal rings resting on their respective bearing sleeves which allow the ‘free’ axial movement of the channel. In support of some maintenance activities, the west end fitting is required to be jacked to get certain clearance for accommodating the operating tools. The previous elastic calculation got the jacking limit of 0.35″ while did not provide enough clearance for tooling. In this paper, an elastic-plastic finite element analysis following ASME B&PV code Section III, Division 1, Subsection NB is performed to increase the jacking limit. The finite element analysis is carried out using ANSYS and validated by an ABAQUS model. In the elastic-plastic finite element analysis, the following effects are considered: strain hardening of stop collar material, stress concentration in stop collar weld, notch effect on stress concentration and fatigue in stop collar. Cyclic jacking loads as displacement controlled loading are applied in the analysis. Considering the time to the end of unit life, the maximum anticipated end fitting jacking cycles are 8. The higher jacking limit is achieved with an acceptable plastic deformation and fatigue damage at the stop collar, which is the weakest part during the end fitting jacking. The results show that the end fitting can be jacked at west side End-face with 1.17″ for 1–3 cycles, 1.15″ for 4 cycles, 1.03″ for 5 cycles, 0.95″ for 6 cycles, 0.85″ for 7 cycles and 0.80″ for 8 cycles. The jacking limits achieved in this paper provide enough clearance for the required maintenance operations.

The Analysis of Mutual Authentication between Finite Element Analysis and Qi Erxi Answer

2011 ◽  
Vol 396-398 ◽  
pp. 1228-1231
Author(s):  
Yu Li Liu ◽  
Hai Bo Liu ◽  
Bo Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Maximum Stress ◽  
Mutual Authentication ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Edge Stress

In this paper, the sheet with hole for the finite element analysis, the location of maximum stress and maximum stress values are obtained under different load of edge of the hole, and the finite element analysis results compared with the classic Qi Erxi answers. This coincidence is not accidental, but it just shows their correctness. Therefore, we can use Qi Erxi answer when the calculation of the hole’s edge stress concentration and the condition of the force and the boundary are simple; while the it is complex, the finite element analysis can be used.

Evaluation of “Linearized” Stresses Without Linearization

2007 ◽  
Author(s):  
Andrzej T. Strzelczyk ◽  
San S. Ho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Shell Element ◽  
Original Model ◽  
Element Analysis ◽  
Solid Element ◽  
The Finite Element Analysis ◽  
Inner Surface ◽  
Element Approach

ASME Code stress assessment of pressure vessels in the power generation industry is usually done by finite element analysis using one of the two approaches. In the first, “shell-element” approach, vessels are modeled out of shell elements; primary plus bending and primary plus secondary stresses are taken directly from the finite element analysis results and the alternating stresses are based on primary plus secondary stresses prorated by respective stress concentration factors. The strength of the “shell-element” approach is its simplicity; its weakness is problematic modeling of the stress concentration and some modeling difficulties (varying wall thickness, nozzle/vessel connectivity, pressure applied to the mid-surface instead of to the inner surface.) In the second, “solid-element” approach, vessels are modeled out of solid elements; “linearized” stresses can not be taken directly from the finite element analysis results, first they must be linearized, and only then, can be compared against their allowable counterparts; the alternating stresses can be based directly on the outer/inner-surface-node-stresses, provided that the mesh of the model is fine enough to account for the stress concentration effect. The strength of the “solid-element” approach is its high accuracy; its weakness is the time consuming, sometimes ambiguous, stress linearization process. This paper proposes a modification of the “solid-element” approach, in which the time consuming linearization process is replaced by a modification of the original model. To do so, a vessel must be modeled out of quadratic 20 node solid elements; the mesh density of the model (on its surface and through thickness) must be adequate for stress concentration representation and the mesh lines in the thickness direction must be more or less normal to the surfaces. The results from this original model can be taken directly for fatigue evaluation. To obtain the “linearized” stresses the original model must be slightly modified, specifically the number of elements through thickness must be reduced to one, and the reduced integration technique is recommended. For such a modified model, the nodal stresses are equivalent to the “linearized stresses” of the original model. The equivalence is discussed on a model of a circular nozzle attached to a cylindrical vessel. The vessel loads are pressure and thermal expansion.

Study on Stress Concentration and Fatigue of Prosthetic Blood Vessels

2013 ◽  
Vol 647 ◽  
pp. 413-417
Author(s):  
Guo Ping Chen ◽  
Shui Wen Zhu
Keyword(s):  
Mechanical Property ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Blood Vessels ◽  
Three Dimensional ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The purpose of this paper is to investigate the stress concentration and fatigue of the prosthetic blood vessels. A three-dimensional finite element analysis was performed with three loading. The good man fatigue thoery was introduced for the fatigue study. As the results, the stress concentration and fatigue mode can be determined. The results prove that the mechanical property of the prosthetic blood vessels can be smiulated through the finite element analysis.

Determination of CANDU End Fitting Jacking Limits Using Elastic–Plastic Finite Element Analysis1

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Bing Li ◽  
David McNeish ◽  
Seyun Eom ◽  
Dk Vijay ◽  
Si-tsai Lin ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
The West ◽  
Reactor Unit ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Division 1 ◽  
The Finite Element Analysis ◽  
Abaqus Model

In one CANDU reactor unit in Ontario, the west end fitting is designed to connect to the end shield via a stop collar. The outboard end of the stop collar is welded to an attachment ring, which shrink-fits on the end fitting body. The east side end fitting is supported by inboard and outboard journal rings resting on their respective bearing sleeves, which allow the “free” axial movement of the channel. In support of some maintenance activities, the west end fitting is required to be jacked to get certain clearance for accommodating the operating tools. The previous elastic calculation got the jacking limit of 8.89 mm, which did not provide enough clearance for tooling. In this paper, an elastic–plastic finite element analysis following ASME B&PV code Section III, Division 1, Subsection NB is performed to increase the jacking limit. The finite element analysis is carried out using ANSYS and validated by an ABAQUS model. In the elastic–plastic finite element analysis, the following effects are considered: strain hardening of stop collar material, stress concentration in stop collar weld, notch effect on stress concentration, and fatigue in stop collar. Cyclic jacking loads as displacement controlled loading are applied in the analysis. Considering the time to the end of unit life, the maximum anticipated end fitting jacking cycles are eight. The higher jacking limit is achieved with an acceptable plastic deformation and fatigue damage at the stop collar, which is the weakest part during the end fitting jacking. The results show that the end fitting can be jacked at west side end-face with 29.7 mm for 1–3 cycles, 29.2 mm for 4 cycles, 26.2 mm for 5 cycles, 24.1 mm for 6 cycles, 21.6 mm for 7 cycles, and 20.3 mm for 8 cycles. The jacking limits achieved in this paper provide enough clearance for the required maintenance operations.

Interactive Graphics for the Analysis of Tires

1985 ◽  
Vol 13 (3) ◽  
pp. 127-146 ◽  
Author(s):  
R. Prabhakaran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Approximate Solutions ◽  
Interactive Graphics ◽  
Element Analysis ◽  
Analysis Process ◽  
Physical Problems ◽  
The Finite Element Analysis ◽  
Analysis Computer ◽  
Discretization Technique

Abstract The finite element method, which is a numerical discretization technique for obtaining approximate solutions to complex physical problems, is accepted in many industries as the primary tool for structural analysis. Computer graphics is an essential ingredient of the finite element analysis process. The use of interactive graphics techniques for analysis of tires is discussed in this presentation. The features and capabilities of the program used for pre- and post-processing for finite element analysis at GenCorp are included.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

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.

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