A Study on Structural Design of Huge Barge Structures Based on Collapsing Behavior and Reliability Analysis

2003 ◽  
Author(s):  
Shinji Katsura ◽  
Hiroo Okada ◽  
Koji Masaoka ◽  
Takashi Tsubogo
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Limit State ◽  
Estimation Method ◽  
Bending Moment ◽  
Irregular Waves ◽  
Elastic Response ◽  
Design Parameters ◽  
Reliability Based Design ◽  
Calculation Results

This paper deals with the limit state and reliability analysis of huge barge structures (HBS) which are supposed floating refuse storage and incineration plant based on collapsing behavior analysis in irregular waves as a part of studies on structural reliability-based design methods. First, a limit state and reliability analysis method is shortly presented for the buckling and ultimate collapse strength of deck, bulkhead and bottom panels of HBS. Next, a simplified method is briefly introduced for collapsing behavior and reliability analysis of HBS under extreme sea loads by using a developed system combined with a finite element method and plastic node method using hexahedral element models. Moreover, a simplified estimation method is shortly introduced for the probabilistic load model considering the hydro-elastic response of the structure in irregular waves. Finally, dominant limit state modes of 1,000m-class HBS under combined loads with bending moment, shearing force and lateral pressure are obtained by applying the above methods. Then, the features of the collapsing behavior and reliability level are investigated by using above calculation results. Effects of statistical values such as reduction of thickness due to corrosion, yield stress and design parameters are also investigated using sensitivity analysis.

A Method for Structural Design of Pontoon Type VLFS Based on Collapse Behavior and Reliability Analysis

2004 ◽  
Author(s):  
Hiroo Okada ◽  
Koji Masaoka ◽  
Takashi Tsubogo ◽  
Shinji Katsura ◽  
Shin-Ichi Kawamata
Keyword(s):  
Reliability Analysis ◽  
Lateral Pressure ◽  
Limit State ◽  
Plate Thickness ◽  
Estimation Method ◽  
Bending Moment ◽  
Irregular Waves ◽  
Design Parameters ◽  
Load Effect ◽  
Collapse Behavior

This paper deals with a simplified method for the preliminary design of pontoon-type very large floating structures (VLFS), which are supposed floating airport, based on collapse behavior and reliability analysis in irregular waves. Firstly, a simplified estimation method is presented for the probabilistic load effect model of VLFS under irregular sea-state conditions. Next, limit state conditions are shortly presented for the buckling and ultimate collapse strength of stiffened plates under combined compression, shear and lateral pressure in the deck, bulkhead and bottom parts of VLFS, especially, by using a simplified estimation formula. Then, the validity is shown by non-linear finite element method. Finally, dominant limit state modes of 5,000m-class VLFS under combined loads with bending moment, shear force and lateral pressure are obtained by applying the above methods. Then, the features of the collapse behavior and reliability level are investigated by using above calculation results. Effects of design parameters such as yield stress, plate thickness, stiffener and bulkhead space are also investigated using sensitivity analysis.

A Simplified Method for Response Behavior and Reliability Analysis of Long Submerged Structures With Tension Legs in Irregular Waves

2002 ◽  
Author(s):  
Shinji Katsura ◽  
Hiroo Okada ◽  
Koji Masaoka ◽  
Takashi Tsubogo ◽  
Kiko Shimada
Keyword(s):  
Limit State ◽  
Experimental Studies ◽  
Estimation Method ◽  
Dynamic Responses ◽  
Irregular Waves ◽  
Elastic Response ◽  
Tunnel Structure ◽  
Wave Loads ◽  
Response Behavior ◽  
Wave Conditions

This paper deals with the elastic response behavior of marine tunnel structures with tension legs in regular and irregular waves. Firstly, a simplified estimation method for dynamic responses under regular wave conditions is analytically presemed using a simple beam on an elastic foundation. Then, in order to demonstrate the validity of above results, experimental studies are carried out for a marine tunnel structure model with tension legs under wave-induced loads. Next, a simplified estimation method is presented for the elastic response behavior under irregular wave conditions by using above analytical results and combining irregular sea wave spectra. Then, the limit state failure mode of the main structure is presented for estimating the reliability level for cracking failure under extreme wave loads. Finally, the applicability of the methods is investigated through numerical examples carried out for a 1,000m-class marine tunnel structure with tension legs under some irregular sea state conditions. And characteristics of the short-term responses and reliability levels for the cracking failure are numerically shown.

Reliability Analysis of Foundation Pit by Improved Response Surface Method

2011 ◽  
Vol 147 ◽  
pp. 197-202 ◽  
Author(s):  
Jiang Zhou ◽  
Jing Cao ◽  
Yu He ◽  
Jie Song
Keyword(s):  
Reliability Analysis ◽  
Response Surface ◽  
Structural Reliability ◽  
Lateral Displacement ◽  
Limit State ◽  
Uniform Design ◽  
Design Parameters ◽  
State Function ◽  
Foundation Pit ◽  
Improved Response Surface Method

Lacking of explicit limit state function (LSF) will result large quantities of computational efforts for a FEAM based structural reliability analysis. An improved response surface (RS) method is proposed to analyze the failure probability of foundation pit through combining uniform design (UD) and non-parametric regression (NPR). Deferent levels of design parameters are first delicately selected according to UD and then FEAM is used to analysis corresponding pit response parameters including maximum lateral displacement of wall, settlement of ground, safety factor of overall stability, safety factors of against overturning, heave and piping. The RS relationship is then established through NPR based on inputs and responses. At last, a direct Mont Carlo Simulation is carried out to obtain the probability density function of response parameters.

scholarly journals Structural Reliability Analysis of Ship Hulls Accounting for Collision or Grounding Damage

2020 ◽  
Author(s):  
Branka Bužančić Primorac ◽  
Joško Parunov ◽  
C. Guedes Soares
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Limit State ◽  
Random Variables ◽  
Bending Moment ◽  
State Equation ◽  
Limit States ◽  
Moment Capacity ◽  
Ship Hulls ◽  
Structural Reliability Analysis

AbstractClassical structural reliability analysis of intact ship hulls is extended to the case of ships with collision or grounding damages. Still water load distribution and residual bending moment capacity are included as random variables in the limit state equation. The probability density functions of these random variables are defined based on random damage parameters given by the Marine Environment Protection Committee of the International Maritime Organization, while the proposed reliability formulation is consistent with international recommendations and thus may be valuable in the development of rules for accidental limit states. The methodology is applied on an example of an Aframax oil tanker. The proposed approach captures in a rational way complex interaction of different pertinent variables influencing safety of damaged ship structure.

Reliability Analysis and Design of Epicyclic Gear Trains

1979 ◽  
Vol 101 (4) ◽  
pp. 625-632 ◽  
Author(s):  
S. S. Rao
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Design Criterion ◽  
Gear Train ◽  
Design Parameters ◽  
Analysis And Design ◽  
Input Shaft ◽  
Reliability Based Design ◽  
Epicyclic Gear ◽  
Gear Trains

The concepts of system reliability are applied for the structural reliability analysis and design of epicyclic gear trains. The reliability analysis is based on the representation of an epicyclic gear train as a series-parallel network. The power transmitted, the speed of the input shaft, the center distance between the gear pairs and the permissible stresses are assumed to be random variables following normal distribution. The layout of the gears and the speed ratios are assumed to be known. The face widths of the gears are taken as random design parameters. The design criterion is that the reliability of the gear train either in bending or surface wear failure mode at any of the output speeds must be equal to a specified value. The design of an epicyclic transmission system which gives four forward speeds and one reverse speed is considered for illustration. The results of the reliability-based design of the gear train are compared with those of the conventional deterministic design.

Response surface method strategies coupled with NLFEA for structural reliability analysis of prestressed bridges

2021 ◽  
Author(s):  
Silvia J. Sarmiento Nova ◽  
Jaime Gonzalez-Libreros ◽  
Gabriel Sas ◽  
Rafael A. Sanabria Díaz ◽  
Maria C. A. Texeira da Silva ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Response Surface ◽  
Response Surface Method ◽  
Structural Reliability ◽  
Limit State ◽  
Material Behavior ◽  
Nonlinear Material ◽  
State Function ◽  
Surface Method ◽  
Highly Nonlinear

<p>The Response Surface Method (RSM) has become an essential tool to solve structural reliability problems due to its accuracy, efficacy, and facility for coupling with Nonlinear Finite Element Analysis (NLFEA). In this paper, some strategies to improve the RSM efficacy without compromising its accuracy are tested. Initially, each strategy is implemented to assess the safety level of a highly nonlinear explicit limit state function. The strategy with the best results is then identified and used to carry out a reliability analysis of a prestressed concrete bridge, considering the nonlinear material behavior through NLFEA simulation. The calculated value of &#120573; is compared with the target value established in Eurocode for ULS. The results showed how RSM can be a practical methodology and how the improvements presented can reduce the computational cost of a traditional RSM giving a good alternative to simulation methods such as Monte Carlo.</p>

The Effect of Sloshing in Tanks on Motions and Hull Girder Responses of Damaged Vessels

2011 ◽  
Author(s):  
Huirong Jia ◽  
Torgeir Moan
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Bending Moment ◽  
Roll Motion ◽  
Multimodal Approach ◽  
Rectangular Shape ◽  
Hull Girder ◽  
Structural Reliability Analysis ◽  
Oil Tankers

The structural reliability analysis of damaged vessels has up to now commonly been investigated by neglecting the effect of sloshing. This paper deals with the effect of sloshing in tanks on motions and hull girder responses of oil tankers in various damage conditions and represents a part of a study to assess the effect of sloshing on hull girder failure of damaged vessels, The flooded tanks are assumed to have a of rectangular shape and linear multimodal approach is adopted to deal with sloshing. It is concluded that even though the effect of sloshing in tanks on the roll motion of vessels can be neglected in certain damage conditions, the effect of sloshing on the horizontal bending moment cannot be neglected, especially when resonance motion occurs.

Experimental Assessment of Form Based Approach for Predicting Extreme Value Distribution of Hull Girder Bending Moment in a Ship

2019 ◽  
Author(s):  
Tomoki Takami ◽  
Yusuke Komoriyama ◽  
Takahiro Ando ◽  
Kazuhiro Iijima
Keyword(s):  
Estimation Method ◽  
Bending Moment ◽  
Extreme Value Distribution ◽  
Irregular Waves ◽  
Extreme Wave ◽  
Scaled Model ◽  
Element Analysis ◽  
Hull Girder ◽  
Reliability Method ◽  
Wave Induced

Abstract This paper describes a series of towing tank tests using a scaled model of a recent container ship for validating the First Order Reliability Method (FORM) based approach to predict the maximum response. The FORM based approach is adopted in conjunction with the nonlinear strip method as an estimation method for the most probable wave episodes (MPWEs) leading to the given extreme wave-induced vertical bending moments (VBMs). Tank tests under the pre-determined MPWEs are conducted to evaluate the extreme wave-induced VBMs. Numerical simulations based on the coupled Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) are also conducted and are compared with the test results under the MPWEs. Furthermore, to estimate the extreme VBM statistics, tank tests under random irregular waves are conducted. A series of validations of the probability of exceedances (PoEs) of the VBM evaluated from the FORM based approach is carried out. The effect of hydroelastic (whipping) vibrations on the extreme VBM statistics are finally discussed.

First-Order Reliability Method for Structural Reliability Analysis in the Presence of Random and Interval Variables

2015 ◽  
Vol 1 (4) ◽  
Author(s):  
Umberto Alibrandi ◽  
C. G. Koh
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Limit State ◽  
Computational Cost ◽  
Computational Effort ◽  
Stochastic Dynamic ◽  
First Order Reliability Method ◽  
First Order ◽  
Structural Reliability Analysis ◽  
Reliability Method

This paper presents a novel procedure based on first-order reliability method (FORM) for structural reliability analysis in the presence of random parameters and interval uncertain parameters. In the proposed formulation, the hybrid problem is reduced to standard reliability problems, where the limit state functions are defined only in terms of the random variables. Monte Carlo simulation (MCS) for hybrid reliability analysis (HRA) is presented, and it is shown that it requires a tremendous computational effort; FORM for HRA is more efficient but still demanding. The computational cost is significantly reduced through a simplified procedure, which gives good approximations of the design points, by requiring only three classical FORMs and one interval analysis (IA), developed herein through an optimization procedure. FORM for HRA and its simplified formulation achieve a much improved efficiency than MCS by several orders of magnitude, and it can thus be applied to real-world engineering problems. Representative examples of stochastic dynamic analysis and performance-based engineering are presented.

An Efficient Reliability Analysis Method for Structures With Epistemic Uncertainty Using Evidence Theory

2014 ◽  
Author(s):  
Zhe Zhang ◽  
Chao Jiang ◽  
G. Gary Wang ◽  
Xu Han
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Epistemic Uncertainty ◽  
Limit State ◽  
Computational Cost ◽  
Evidence Theory ◽  
State Function ◽  
Limited Information ◽  
Design Point ◽  
Engineering Problems

Evidence theory has a strong ability to deal with the epistemic uncertainty, based on which the uncertain parameters existing in many complex engineering problems with limited information can be conveniently treated. However, the heavy computational cost caused by its discrete property severely influences the practicability of evidence theory, which has become a main difficulty in structural reliability analysis using evidence theory. This paper aims to develop an efficient method to evaluate the reliability for structures with evidence variables, and hence improves the applicability of evidence theory for engineering problems. A non-probabilistic reliability index approach is introduced to obtain a design point on the limit-state surface. An assistant area is then constructed through the obtained design point, based on which a small number of focal elements can be picked out for extreme analysis instead of using all the elements. The vertex method is used for extreme analysis to obtain the minimum and maximum values of the limit-state function over a focal element. A reliability interval composed of the belief measure and the plausibility measure is finally obtained for the structure. Two numerical examples are investigated to demonstrate the effectiveness of the proposed method.

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