A Procedure for Non-Linear Structural Collapse Analysis

2014 ◽  
Author(s):  
Shengming Zhang ◽  
Lei Jiang
Keyword(s):  
Structural Engineering ◽  
Standard Procedure ◽  
Analysis Procedure ◽  
Structural Collapse ◽  
Element Analysis ◽  
Collapse Analysis ◽  
Non Linear ◽  
Mesh Density ◽  
The Difference ◽  
Offshore Industry

It is a normal practice nowadays in structural engineering, including ships and offshore industry, to perform non-linear finite element analysis to assess the structure’s capacity for design or evaluation purposes. However, experience has shown that the quality and accuracy of the non-linear FE analysis results are highly dependent on the skill of the person performing the analysis and the analysis procedure used. The difference between results obtained by different people can be significant. In some cases, the results can be misleading. It is considered that a unified procedure is necessary. This paper is moving a step further and trying to develop a standard procedure which can provide a guideline for structural collapse analysis of stiffened panels under any load combinations. The paper provides the technical background on the analysis procedure and the key steps such as model extent, mesh density, initial imperfections, and boundary conditions. Analysis examples are provided in the paper for reference and discussions.

A Method for Ultimate Strength Assessment of Plates in Combined Stresses

2015 ◽  
Author(s):  
Shengming Zhang ◽  
Lei Jiang
Keyword(s):  
Ultimate Strength ◽  
Structural Engineering ◽  
Fe Analysis ◽  
Strength Analysis ◽  
Element Analysis ◽  
Simple Method ◽  
Strength Assessment ◽  
Industry Standards ◽  
Non Linear ◽  
Offshore Industry

It is becoming a normal practice in structural engineering, including ships and offshore industry, to perform non-linear finite element analysis to assess the structure’s capacity for design or evaluation purposes. However, experience has shown that the quality and accuracy of the non-linear FE analysis results are highly dependent on the person’s skills and analysis procedures used. In some cases, the results could lead to a wrong conclusion. Simplified method with good accuracy is still a preferred approach in design by the industry because it is simple and easy to use. However, even the method for the simple model, a plate under combined loads, has not been addressed completely because of its complexity. This paper has thus developed a simple method for the ultimate strength analysis of square plates under combined longitudinal and transverse compressive stresses. The method is fully validated with a systematic non-linear FE analysis results. The paper has also compared the methods from the industry standards BS5400 and DIN18800. Analysis examples are also provided in the paper for reference and discussions.

Validating FEA Simulations of Structural Collapse of a Complex Vessel Geometry

2016 ◽  
Author(s):  
J. Adin Mann ◽  
Brandon Yost ◽  
Gregory Westwater ◽  
Christopher R. Johnson ◽  
Brett Pollock ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Complex Geometry ◽  
Control Valve ◽  
Structural Collapse ◽  
Working Pressure ◽  
Element Analysis ◽  
Testing Procedures ◽  
Linear Elastic ◽  
Section Viii ◽  
The Difference

Part 5 in Section VIII Division 2 of the ASME Boiler & Pressure Vessel Code provides methods for evaluating stresses in pressure vessel components using Finite Element Analysis (FEA). Both linear elastic and inelastic methods are provided. Validating the FEA simulations can be challenging because of testing procedures as well as variation between the test parts. Control valve bodies, which have a complex geometry, were tested to pressures far beyond the maximum allowable working pressure to evaluate behavior at structural collapse. The test bodies were scanned so that the true geometry was used in the FEA simulations. FEA simulations were used to perform a linear elastic evaluation and inelastic evaluations. The inelastic evaluation included various material models. The difference between a point by point comparison and outcome based validation are discussed.

Blast Mitigation Design for Urban Steel Structures Subjected to Close- in Detonations

2019 ◽  
Author(s):  
Yongwook Kim ◽  
Jarett Rooney
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Engineering ◽  
Steel Structures ◽  
Charge Weight ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Non Linear ◽  
Close Range

<p>More frequent terrorist attacks to civilians, buildings, and infrastructures have been observed in recent years, which occasionally resulted in significant fatalities, financial damages, and service interruptions due to collapses of the structures. The collapse of a structure can be triggered by substantial or complete damages of essential structural members, potentially resulting from close-range detonations. Close-range detonations can be fatal even with a small portable charge weight. Many structures in major international cities are potentially exposed to close-range detonations, simply because there is no room to maintain a sufficient stand-off distance around each structural member. Current available approaches to blast resistant designs are focusing on far-range detonations; for close-range detonations, a non-linear explicit finite element analysis is required, instead. Most structural engineering firms do not have access to the analyses, because the details of the analysis are not readily available. In the present study, some details of the non-linear explicit finite element analysis are presented for close-range detonations. The same method is applied to numerical parametric studies for a standard steel column subjected to a range of charge weights and stand-off distances. In the study, the development of a performance-based engineering chart is discussed, which can be used by general structural engineers without performing the numerical analysis. A few practical strengthening layers of steel members are also investigated to effectively mitigate potential damages from close-range detonations.</p>

Behaviour of Axially Loaded Composite Wall Panel by Using Finite Element Analysis

2015 ◽  
Vol 815 ◽  
pp. 49-53
Author(s):  
Nur Fitriah Isa ◽  
Mohd Zulham Affandi Mohd Zahid ◽  
Liyana Ahmad Sofri ◽  
Norrazman Zaiha Zainol ◽  
Muhammad Azizi Azizan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Element Analysis ◽  
Steel Sheets ◽  
Linear Behavior ◽  
Non Linear ◽  
Composite Wall ◽  
Experimental Values ◽  
Civil Engineering Infrastructure

In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to behavior is concerned, it is well known that a key step is to investigate the influence of geometric differences on the non-linear behavior of the panels. One possible approach is to use the validated numerical model based on the non-linear finite element analysis (FEA). The validation of the composite panel’s element using Trim-deck and Span-deck steel sheets under axial load shows that the present results have very good agreement with experimental references. The developed finite element (FE) models are found to reasonably simulate load-displacement response, stress condition, giving percentage of differences below than 15% compared to the experimental values. Trim-deck design provides better axial resistance than Span-deck. More concrete in between due to larger area of contact is the factor that contributes to its resistance.

Reliability Analysis of Jack-Up Platforms Based on Fatigue Degradation

2002 ◽  
Author(s):  
Naser Shabakhty ◽  
Pieter van Gelder ◽  
Hotze Boonstra
Keyword(s):  
Service Time ◽  
Great Part ◽  
Fatigue Reliability ◽  
Original Design ◽  
Operational Conditions ◽  
Stress Fluctuation ◽  
The Difference ◽  
Offshore Industry ◽  
Jack Up ◽  
Load Conditions

Generally, jack-up structures are used for production drilling and exploration of hydrocarbons. The combination of mobility and the behavior as a fixed structure in operational conditions has made it an important structure in the offshore industry over the last 40 years. When a jack-up structure has been in operation for a great part of its original design-life and intention is there to extend the usage of this structure at a specific location, an investigation on fatigue degradation of the structure is an essential factor that has to be carried out before taking any decision. Fatigue is the process of damage accumulation in material due to stress fluctuation caused by variation of loads in service time. The fatigue failure occurs when accumulated damage has exceeded a critical level. In this paper, the remaining fatigue capacity of the jack-up structure is considered as an indicator for adequate use of the structure. It can be specified based on the difference between design-fatigue and fatigue experienced by the structure. The design-fatigue can be determined based on fluctuation of loads during the lifetime of the structure and experienced fatigue is specified by the load conditions, which the structure has experienced during its service time. When the information on the load conditions which the structure has experienced in its service time is available or known precisely, determination of the remaining fatigue capacity could be carried out by using the Palmgren–Miner’s rule. In practice, uncertainties are present in loads and characteristics of material. Hence it will be reasonable to determine the remaining fatigue reliability of the structure by the reliability methods. In this paper, based on a crack propagation approach and achieved information from inspection, it is shown that the remaining fatigue reliability of jack-up structures could be determined and updated by using a Bayesian procedure in the duration of the service time.

Finite Element Analysis of Creep Damage Behavior Near the Cavity on Bimaterial Interface

2006 ◽  
Vol 324-325 ◽  
pp. 951-954 ◽  
Author(s):  
Qing Min Yu ◽  
Zhu Feng Yue ◽  
Yong Shou Liu
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Elastic Stress ◽  
Creep Damage ◽  
Ductile Material ◽  
Bimaterial Interface ◽  
Modulus Ratio ◽  
Element Analysis ◽  
Damage Law ◽  
The Difference

Fracture along an interface between materials plays a major role in failure of material. In this investigation, finite element calculations with Kachanov–Rabotnov damage law were carried out to study the creep damage distribution near the interface cavity in bimaterial specimens. The specimens with central hole were divided into three types. The material parameters of K-R law used in this paper were chosen for a brittle material and ductile material. All calculations were performed under four load cases. Due to the difference between elastic moduli of the bounded materials, the elastic stress field as a function of the Young’s modulus ratio (R=E1/E2) was determined. At the same time, the influence of model type on elastic stress distribution near the cavity was considered. Under the same conditions, the material with larger modulus is subjected to larger stress. The creep damage calculations show that the location of the maximum damage is different for each model. The distributions of creep damage for all three models are dependent on the material properties and load cases.

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