Nonlinear Structural Consequence Analysis of FPSO Topsides Under Fire

2012 ◽  
Author(s):  
Jeong Hwan Kim ◽  
Du Chan Kim ◽  
Cheol Kwan Kim ◽  
Md. Shafiqul Islam ◽  
Jeom Kee Paik
Keyword(s):  
Structural Response ◽  
Fire Risk ◽  
Offshore Structures ◽  
Nonlinear Material ◽  
Response Analysis ◽  
Element Analysis ◽  
Practical Procedure ◽  
Consequence Analysis ◽  
Nonlinear Structural ◽  
Structural Consequence

This study aims to develop a practical procedure for the nonlinear structural consequence analysis of structures under fire. The thermal and structural response analysis have been performed in this study using a commercial nonlinear Finite Element Analysis (FEA) code. The results of the structural response analysis are then compared to the experimental results. This study concludes by presenting methods for fire load applications and nonlinear material modeling. The insights offered by the modeling techniques and analysis procedures presented in this study should be very useful and practical in the fire risk assessment of offshore structures.

Nonlinear Structural Consequence Analysis of Blast Wall Structures Under Hydrocarbon Explosive Loads

2012 ◽  
Author(s):  
Jung Min Sohn ◽  
Byoung Hoon Kim ◽  
Jeom Kee Paik ◽  
Graham Schleyer
Keyword(s):  
Risk Assessment ◽  
Finite Element ◽  
Structural Response ◽  
Offshore Structures ◽  
Response Analysis ◽  
Offshore Platforms ◽  
Element Analysis ◽  
Practical Procedure ◽  
Nonlinear Structural ◽  
Wall Structures

Many accidents that occur on offshore structures, especially explosions, are extremely hazardous. Violent explosions can have serious consequences for health, safety, and the marine environment. The topsides of offshore platforms are the most likely areas to be exposed to hazards such as hydrocarbon explosions. Therefore, profiled barriers are being increasingly used as blast walls in offshore topsides modules to provide a safety barrier for personnel and critical equipment. The aim of this study is to develop a practical procedure for the nonlinear structural response analysis of corrugated blast walls under explosion. Within the framework of quantified risk assessment and management of offshore installations, more refined computations are required to assess the consequences or hazardous action effects of explosions. In addition, appropriate guidance will be presented on the use of the finite element numerical tool for the above purpose. The structural response has been computed using commercial nonlinear finite element analysis (NLFEA) code and the results compared with the single degree of freedom (SDOF) method. The relationships between blast pressure and the impulse of corrugated blast walls are developed. This study’s insights into modeling techniques and procedures will be applicable to the explosion risk assessment of offshore structures.

scholarly journals Evaluation of Nonlinear Material Behavior for Offshore Structures Subjected to Accidental Actions

2017 ◽  
Author(s):  
Martin Storheim ◽  
Hagbart S. Alsos ◽  
Jørgen Amdahl
Keyword(s):  
Structural Response ◽  
Offshore Structures ◽  
The Body ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Strain Rate Effects ◽  
Nonlinear Structural ◽  
Rate Effects ◽  
High Degree ◽  
Nonlinear Structural Response

Evaluation of the nonlinear structural response of any structure is a challenging task; a range of input parameters are needed, most of which has significant statistical variability and the evaluations require a high degree of craftsmanship. Hence, high demands are set forth both to the analyst and the body in charge of verification of the results. Recent efforts by DNVGL attempts to mitigate this with the second edition of the DNVGL-RP-C208 for determination of nonlinear structural response, in which guidance or requirements are given on many of the challenging aspects. This paper discuss the various challenges and the direction to which the RP-C208 points compared to published research. Parameters affecting the plastic hardening, strain-rate effects and ductile fracture are discussed separately. Then, the combined effect of the range of assumptions is evaluated to assess the resulting level of safety.

scholarly journals Evaluation of Nonlinear Material Behavior for Offshore Structures Subjected to Accidental Actions

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Martin Storheim ◽  
Hagbart S. Alsos ◽  
Jørgen Amdahl
Keyword(s):  
Structural Response ◽  
Offshore Structures ◽  
The Body ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Strain Rate Effects ◽  
Nonlinear Structural ◽  
Rate Effects ◽  
High Degree ◽  
Nonlinear Structural Response

Evaluation of the nonlinear structural response of any structure is a challenging task; a range of input parameters are needed, most of which have significant statistical variability and the evaluations require a high degree of craftsmanship. Hence, high demands are set forth both to the analyst and the body in charge of verification of the results. Recent efforts by DNVGL attempt to mitigate this with the second edition of the DNVGL-RP-C208 for the determination of nonlinear structural response, in which guidance or requirements are given on many of the challenging aspects. This paper discusses the various challenges and the direction to which the RP-C208 points compared to published research. Parameters affecting the plastic hardening, strain-rate effects, and ductile fracture are discussed separately. Then, the combined effect of the range of assumptions is evaluated to assess the resulting level of safety.

A New Procedure for the Nonlinear Structural Response Analysis of Offshore Installations in Fires

2013 ◽  
Author(s):  
Jeom Kee Paik ◽  
Jerzy Czujko ◽  
Jeong Hwan Kim ◽  
Sung In Park ◽  
Shafiqul Islam ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Thermal Response ◽  
Structural Response ◽  
Fire Risk ◽  
Response Analysis ◽  
Nonlinear Structural ◽  
Offshore Installations ◽  
Fire Loads ◽  
Structural Responses ◽  
Nonlinear Structural Response

The quantitative assessment and management of the risks associated with fire require integrated computations of fire loads and their consequences. The objective of this paper is to present a new procedure for the nonlinear structural response analysis of offshore installations during fires. The procedure comprises calculation of fire loads using computational fluid dynamics (CFD) simulation, thermal response analysis and nonlinear structural response analysis in fire which are key elements in the framework of the fire risk assessment and management. KFX code is used to perform the fire CFD simulation; whereas the analyses of both thermal and nonlinear structural responses are performed using the LS-DYNA code. Models for such analysis can be developed with shell elements to represent the structures with required accuracy. A computer program known as KFX2DYNA is applied to automatically import the results of the KFX simulations which are directly exported to LSDYNA for the analyses of both heat transfer and nonlinear structural responses, making fire risk analysis fast, accurate and reliable. An experimental scenario with a simply supported I-girder under fire is used to validate the procedure. The applicability of the procedure is demonstrated using the example of a fire in the hypothetical topside structure of a VLCC-class FPSO.

Nonlinear structural consequence analysis of FPSO topside blastwalls

2013 ◽  
Vol 60 ◽  
pp. 149-162 ◽  
Author(s):  
Jung Min Sohn ◽  
Sang Jin Kim ◽  
Byoung Hoon Kim ◽  
Jeom Kee Paik
Keyword(s):  
Consequence Analysis ◽  
Nonlinear Structural ◽  
Structural Consequence

Finite Element Analysis of Unbonded Prestressed Concrete Silos

2014 ◽  
Vol 578-579 ◽  
pp. 60-65
Author(s):  
Guang Shu Xu ◽  
Huan Qin Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Prestressed Concrete ◽  
Seismic Analysis ◽  
Structural Response ◽  
Response Analysis ◽  
Element Analysis ◽  
Paper Making ◽  
Pile Caps ◽  
Prestressed Reinforcement

in this paper, making coal storage silo that diameter is a 120 m as the background, researched warehouse wall and pile caps using finite element method. In articles, the finite element analysis of soil, study the influence of prestressed reinforcement about prestressed effect, the structural response analysis under different stack forms and seismic analysis. The results show that: inside and outside temperature difference makes maximum stress, full load can reflect the other coal pile forms, the ability of resist the earthquake is strong.

scholarly journals Structural Performance Evaluation for Vibration-based Energy Harvester utilized in Railway Vehicle

2018 ◽  
Vol 167 ◽  
pp. 02003
Author(s):  
Ki-Weon Kang ◽  
Ji-Won Jin
Keyword(s):  
Performance Test ◽  
Energy Harvester ◽  
Structural Integrity ◽  
Structural Response ◽  
Structural Performance ◽  
Railway Vehicle ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Element Analysis ◽  
Vibration Energy Harvester

This study aims to assess the structural performance and structural integrity of vibration energy harvester (VEH). For this, the structural performance test were conducted to identify the natural frequency and structural response against frequency. And then, static structural analysis was performed using finite element analysis to investigate the failure critical locations (FCLs). Finally, we conducted the frequency response analysis in frequency domain to obtain the structural response with frequency and investigate the structural integrity of VEH. Using the above results, we assessed the structural performance and structural integrity of two types of VEHs.

A New Procedure for the Nonlinear Structural Response Analysis of Offshore Installations in Explosions

2014 ◽  
Author(s):  
Jeom Kee Paik ◽  
Jerzy Czujko ◽  
Sang Jin Kim ◽  
Jong Chan Lee ◽  
Bong Ju Kim ◽  
...  
Keyword(s):  
Structural Response ◽  
Response Analysis ◽  
Shell Elements ◽  
Nonlinear Structural ◽  
Offshore Installations ◽  
Industry Practice ◽  
Design Values ◽  
Structural Responses ◽  
Explosion Accidents ◽  
Nonlinear Structural Response

This paper is a sequel to the previous two papers by the authors presented at SNAME annual meetings in 2012 and 2013. The key tasks for measuring and managing risks associated with hydrocarbon explosions include defining explosion loads and computing structural responses. In industry practice, such response analysis often involves applying uniformly distributed explosion loads to structures according to their nominal design values. However, uniformly distributed loads based on nominal values of structural design may not always fully reflect the actual situations of real explosion accidents, mainly because the actual characteristics of both explosion loads and structural responses are extremely nonlinear. Therefore, it is highly desirable to identify the non-uniform distributions of explosion loads and directly apply them to structures for the response analysis. To accomplish this, technical challenges must be met in terms of refined computations for loads, structural responses and interfaces between load definitions and structural analyses. This study develops a new procedure to resolve such challenges. In this procedure, FLACS computational fluid dynamics (CFD) simulations are applied to the characterization of blast loads. ANSYS/LS-DYNA nonlinear finite element methods (using plate-shell elements) are applied for nonlinear structural response analysis, and a computer program named FLACS2DYNA is developed to automatize the direct export of the FLACS simulations to the ANSYS/LS-DYNA computations. The contribution of this study is demonstrated through an applied example using a hypothetical topside structure of a VLCC-class FPSO that is exposed to hydrocarbon explosions. This example shows that the developed procedure can enable fast, accurate and reliable nonlinear structural response analysis, and subsequently allow better assessment and management of explosion risks.

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