Research on the Crashworthiness of FLNG Side Structures in the Side-by-Side Offloading Operation With LNGC

Author(s):  
Dongwei Zhang ◽  
Zhiqiang Hu ◽  
Gang Chen

On purpose of evaluating the crashworthiness of FLNG side structures in case of the collision accident during the side-by-side offloading operation, a unique research is conducted in this paper with numerical simulation method. According to the model test completed in Deepwater Offshore Basin in Shanghai Jiao Tong University, there does exist a high probability of collision between FLNG and LNGC in the side-by-side offloading operation. To perform numerical simulations, finite element models were built. For the FLNG model, the side structures contain the detailed LNG cargo containment system. According to the parameters obtained from the model test, two typical collision scenarios are defined. Then the collision scenarios are simulated by the LS_DYNA code. A special limit collision state is proposed based on the structural response of LNG CCS. With respect to the numerical results, great attention is paid to the structural response of CCS to evaluate the safety of FLNG side structures. Furthermore, some insights useful for the basic design of FLNG are put forward.

2012 ◽  
Vol 229-231 ◽  
pp. 55-58
Author(s):  
Jun Fan

To obtain the know-how of the deficiency for the filling capability, taking Ti75 alloy as the research object, at the same height of reducing, strain rates during forming as the control objective, the finite element numerical simulation method was used to simulate the hot compression with DEFORM-3D, analyzing the effect of the strain rates on the distribution of strain and stress.


2013 ◽  
Vol 734-737 ◽  
pp. 1488-1492
Author(s):  
Zhen Yu Liu ◽  
Li Hong Yao ◽  
Hu Zhen Wang ◽  
Cui Cui Ye

The fractures after artificial steering fracturing appear in shades of curved surface. Aiming at the problem of steering fracture, in the paper, numerical simulation method under the condition of three-dimensional two-phase flow is presented based on finite element method. In this method, of steering fracture was achieved by adopting surface elements fractures and tetrahedron elements to describe formation. By numerical simulation, the change rule of oil and water production performance of steering fractures can be calculated, and then the steering fracture parameters can be optimized before fracturing. A new method was supplied for the numerical simulation of artificial fractured well.


Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 337 ◽  
Author(s):  
Jian Xing ◽  
Yan-yan Cheng ◽  
Zhuo Yi

To improve the effect of multi-point stretch forming of sheet metal, it is proposed in this paper to replace a fixed ball head with a swinging ball head. According to the multi-point dies with different arrangements, this research establishes finite element models of the following stretch forming, i.e., fixed ball heads with conventional arrangement, swinging ball heads with conventional arrangement, swinging ball heads with declining staggered arrangement, and swinging ball heads with parallel staggered arrangement, and then numerical simulation is performed. The simulation results show that by replacing a fixed ball head with a swinging ball head, the surface indentation of the part formed was effectively suppressed, the stress and tension strain distribution of the part formed was improved, and the forming quality was improved; the thickness of the elastic pad was reduced, the springback was reduced and the forming accuracy was improved; and when the ball head was applied to a multi-point die with staggered arrangement, a better forming result was achieved, where the best forming result was achieved in combining the swinging ball heads with the multi-point die with a parallel staggered arrangement. Forming experiments were carried out, and the experimental results were consistent with the trend of numerical simulation results, which verified the correctness of the numerical simulation.


2015 ◽  
Vol 750 ◽  
pp. 153-159
Author(s):  
Jie Dong ◽  
Xue Dong Chen ◽  
Bing Wang ◽  
Wei He Guan ◽  
Tie Cheng Yang ◽  
...  

The upper and lower courses of sea oil and gas exploitationare connected by submarine pipeline which is called life line project. Free span often occurs because of the unevenness and scour of seabed, and fatigue is one of the main failure modes.In this paper, with the finite element numerical simulation method, based on the harmonic response analysis, the research on the structural response of free span under the vibration induced by vortex was investigated, and the effect of the factors such as flow velocity, length of free span. According to the analysis results,the fatigue life of free span was evaluated.


Author(s):  
Zhiqiang Hu ◽  
Zhenhui Liu ◽  
Jo̸rgen Amdahl

The characters of the collision scenario when a semi-submersible is struck by a containership are studied in this paper, through the model test, simplified analytical method and numerical simulation. The model test is conducted in the Deepwater Offshore Basin in Shanghai Jiao Tong University. Two special devices are designed to fulfill the model test. One is Ship Launching Device, simplified as SLD, who can launch the striking ship with controllable velocity and in any horizontal direction. The other is Energy Absorbing Device, simplified as EAD, who can simulate the buffer effect of the column structure and collect the collision force as well. A numerical simulation is completed to get the approximate stiffness of the column structure, which is used to adjust the property of EAD. The motions of semi-submersible are obtained, and the collision force and the tension forces of mooring lines are also got. Collision scenario characters for semi-motion and tension force are summarized by the analysis of the model test results. The second collision phenomenon is observed. The collision force dominates the collision moment and the tension force of the mooring lines lags behind. A NTNU in-house program developed by analytical simplified method is also verified by the model test result. The comparison proves the feasibility of the program.


2021 ◽  
Author(s):  
Long Ma ◽  
Ping Ai ◽  
ChuanSheng Xiong

Abstract Aiming at the low simulation accuracy of the numerical simulation method of the joint response of the super-large section underground comprehensive pipeline gallery under the current complicated geological conditions, a numerical simulation method of the joint response of the super-large section underground comprehensive pipe gallery joint response under the complicated geological conditions based on the finite element model was proposed. According to the analysis process for the super-large section underground comprehensive pipe gallery, the viscous boundary of the comprehensive pipe gallery is determined. Additionally, by analyzing soil and structural parameters, the optimal combined dynamic boundary is used as the model boundary. The HSS model is used to describe the constitutive structure of the soil, and by improving the Goodman element to describe the contact surface of the model, the finite element model of the joint response of the comprehensive pipe gallery is constructed. Furthermore, based on the internal force balance and deformation coordination conditions, considering the influence of the deformation shape of the joint joints and the elongation of the prestressed tendons on the finite element model, the response model of the integrated pipe gallery joint is optimized. Experimental results show that the proposed method has higher numerical simulation accuracy.


Author(s):  
Kisu Lee

By modifying the contact point displacement with a simple and systematic way, it has been explained that the node-to-segment contact solution can become as accurate as that of the node-to-node contact constraint. The accuracy of the solution is demonstrated by the numerical simulation using a punch sliding on the slab.


2014 ◽  
Vol 17 (11) ◽  
pp. 1601-1621 ◽  
Author(s):  
Nima Khorsandnia ◽  
Hamid Valipour ◽  
Keith Crews

This paper presents the structural response of timber-concrete composite (TCC) beams predicted by finite element models (i.e. continuum-based and 1D frame) and manual calculations. Details of constitutive laws adopted for modelling timber and concrete are provided and application of the Hashin damage model in conjunction with continuum-based FE for capturing failure of timber under bi-axial stress state is discussed. A simplified strategy for modelling the TCC connection is proposed in which the connection is modelled by a nonlinear spring and the full load-slip behaviour of each TCC connection is expressed with a formula that can be directly implemented in the general purpose FE codes and used for nonlinear analysis of TCC beams. The developed FE models are verified by examples taken from the literature. Furthermore, the load-displacement response and ultimate loading capacity of the TCC beams are determined according to Eurocode 5 method and compared with FE model predictions.


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