The Study on Hull Structure Strength Analysis and Opening Calculation of CJ46 Jack-Up Drilling Unit

2015 ◽  
Author(s):  
Zeng Ji ◽  
Chen Gang ◽  
Mo Jian ◽  
Wang Yuhan ◽  
Zhang Wei
Keyword(s):  
Yield Strength ◽  
Element Model ◽  
Strength Analysis ◽  
Ocean Engineering ◽  
Engineering Structures ◽  
Hull Structure ◽  
Key Issues ◽  
Drilling Unit ◽  
Main Support ◽  
Jack Up

The structural strength of jack-up units is the key issues in the design of ship and ocean engineering structures. Based on ABS MODU, the yield strength of CJ46 self-elevating drilling platform main hull structure is checked. Firstly, the environmental loads (wind, wave and flow) in three loading conditions which are required by specification are calculated by using GeniE (DNV). Then the 3D finite element model of main hull structure is established. The yield strength is checked and the results shown the large stress areas are leg well, jackcase which is connected with the leg and bulkhead which is main support structure under the cantilever sliding device, while the results meet the requirements of ABS MODU. Finally, the influence of the openings located in main longitudinal bulkheads are evaluated, meanwhile the main longitudinal bulkheads under skidding box need particular concern.

Shakedown Analysis of Ocean Engineering Structures Subjected to Repeated Dynamic Loads

2014 ◽  
Author(s):  
Wang Jun ◽  
Xiongliang Yao ◽  
Zhang A'man
Keyword(s):  
Shell Thickness ◽  
Theoretical Method ◽  
Dynamic Loads ◽  
Strength Analysis ◽  
Ocean Engineering ◽  
Wave Load ◽  
Wave Impact ◽  
Engineering Structures ◽  
Shakedown Analysis ◽  
Important Place

Ocean engineering structures are frequently subjected to repeated dynamic loads caused by slamming of wave, impact of ice, dropped objects, collisions of store ship and grounding. Shakedown analysis is an extension of plastic limit analysis. Meanwhile, the dynamic strength analysis and shakedown analysis of offshore platform structure have an important place in ensuring the safety and reliability of ocean engineering structures under repeated dynamic loads. Therefore the shakedown analysis theory was introduced to the ultimate strength analysis of brace strut of semisubmersible drilling platform considering cyclic wave load. Based on the kinematic shakedown theorem, a theoretical method of shakedown analysis for typical ocean engineering structures under repeated dynamic loads was presented and compared with existing results to verify the reasonableness. According to the method of finite elastic-plastic theory, the strength of brace strut was analyzed through the overall model of semisubmersible drilling platform. Then based on the boundary conditions getting from the overall three-dimensional model, locally refined model of brace strut was obtained. By applying the theoretical method to shakedown analysis of brace strut under repeated dynamic loads, influence of shell thickness, stiffener thickness and stiffener spacing on shakedown limit were studied. The results show that the theoretical calculation method is consistent with the existing results. The limit load increases with the increase of shell thickness and stiffener thickness, while decreases with the increase of stiffener spacing.

Load Generation for Structural Strength Analysis of Large Containerships

2008 ◽  
Author(s):  
Jo¨rg Ro¨rup ◽  
Thomas E. Schellin ◽  
Helge Rathje
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Integrity ◽  
Element Model ◽  
Strength Analysis ◽  
Rule Based ◽  
Hull Structure ◽  
Global Strength ◽  
The Finite Element Model ◽  
Load Generation

Many modern ships, particularly large containerships, are characterized by extreme bow flare, large stern overhang, and low torsional rigidity due to an open deck structural configuration. Software package GL ShipLoad was developed as an aid to assess the structural integrity of such ships. This software tool became the standard method to generate rule based loads for a global strength finite element analysis of sea going displacement ships. It efficiently generates loads based on first principles. A graphical user interface facilitates the convenient application of ship and cargo masses to the finite element model and aids in the selection of relevant design wave situations. User defined selection criteria, such as maximum values of rule based bending moments, shear forces, or torsional moments, specify which waves have to be chosen for the global strength analysis. This approach yields a reduced number of balanced load cases that are sufficient to dimension the hull structure. To adequately simulate roll motion, additional roll angles are analyzed that simulate realistic distributions of torsional moments over the ship length. A strength analysis of a typical post-panamax containership demonstrated the load generation procedure. First, efficiently modeled mass items were grouped into reusable assembled masses for the ship at hydrostatic equilibrium. Second, regular design wave scenarios were estimated, and hydrodynamic pressures for a large number of regular waves were computed. Third, a reduced number of relevant wave situations were automatically selected, and balanced hydrostatic, hydrodynamic, and inertia loads were applied to the finite element model. Enforced roll angles were found to contribute significantly to the initial torsional moment in the fore holds. Finally, based on a locally refined FE submodel of the hatch corners in way of the ship’s fore hold, a fatigue analysis was performed to assess effects of critical loading under enforced roll angles.

Global Structural Response Analysis of Jack-Up Ship in Transit Condition

2013 ◽  
Vol 344 ◽  
pp. 66-69
Author(s):  
Xiang Zhu ◽  
Yong Sheng Tang ◽  
Yao Zhao ◽  
Heng Kui Ye
Keyword(s):  
Structural Response ◽  
Bending Moment ◽  
Element Model ◽  
Inertia Force ◽  
Response Analysis ◽  
Wave Loads ◽  
Critical Areas ◽  
Hull Structure ◽  
In Transit ◽  
Jack Up

The global structural response of a four-leg jack-up wind turbine installation ship in the transit condition was analyzed in this paper. The finite element model of the hull and legs were established with the Software MSC. PATRAN. On the basis of long-term forecast of the wave loads, the corresponding designed wave parameters are determined with the vertical wave bending moment of the midship cross section served as the main load control parameter. Considering the gravity, hydrostatic pressure, the hydrodynamic loads induced by the wave, inertia force induced by the motion and acceleration of the ship and the wind force on the legs and hull, the direct calculated method was used to evaluate the global structural response of the vessel. The deformation and stress of the hull and legs were calculated and checked. The results showed that the strength of the hull and leg could meet the rules requirements. For the jack-up ship in the transit condition, the critical areas are mainly lower part of legs and the corresponding hull structure.

Structural Strength Analysis of Main Crane Pedestal of the Jack-Up Wind Turbine Installation Vessel

2013 ◽  
Vol 351-352 ◽  
pp. 7-12
Author(s):  
Xiang Zhu ◽  
Yong Sheng Tang ◽  
Fei Xiang Li ◽  
Yao Zhao
Keyword(s):  
Wind Turbine ◽  
Structural Strength ◽  
Limit State ◽  
Offshore Wind ◽  
Strength Analysis ◽  
Ultimate Limit State ◽  
Fe Model ◽  
Hull Structure ◽  
Jack Up ◽  
Turbine Installation

The jack-up wind turbine installation vessel is a special kind of vessel for building the offshore wind power farm. The main crane pedestal, which is the supporting structure of the crane on the main deck of the vessel, is always under high level loads when the ship is in operation condition. In this paper, the structural strength analysis of main crane pedestal of the jack-up wind turbine installation vessel was presented. The direct calculated method was used to evaluate the strength of the main crane pedestal. The FE model of main crane pedestal was established with refined mesh, and the adjoining hull structure was also modeled to provide accurate boundary condition. Considering the permanent loads, variable loads (crane loads) and wind loads on the pedestal, the load combinations were defined for the ultimate limit state for every 45 degree. The deformation and stress of the pedestal and the hull structures were calculated and checked. The results showed that all stress results were within the maximum allowable stresses. The critical areas are often located at the link region of hull and pedestal.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

scholarly journals Monitoring the dynamic behaviors of the Bosporus Bridge by GPS during Eurasia Marathon

2007 ◽  
Vol 14 (4) ◽  
pp. 513-523 ◽  
Author(s):  
H. Erdoğan ◽  
B. Akpınar ◽  
E. Gülal ◽  
E. Ata
Keyword(s):  
Frequency Domain ◽  
Element Model ◽  
Traffic Load ◽  
Suspension Bridges ◽  
Engineering Structures ◽  
Low Frequencies ◽  
Temperature Changes ◽  
Bridge Responses ◽  
Special Complex ◽  
Short Time

Abstract. Engineering structures, like bridges, dams and towers are designed by considering temperature changes, earthquakes, wind, traffic and pedestrian loads. However, generally, it can not be estimated that these structures may be affected by special, complex and different loads. So it could not be known whether these loads are dangerous for the structure and what the response of the structures would be to these loads. Such a situation occurred on the Bosporus Bridge, which is one of the suspension bridges connecting the Asia and Europe continents, during the Eurasia Marathon on 2 October 2005, in which 75 000 pedestrians participated. Responses of the bridge to loads such as rhythmic running, pedestrian walking, vehicle passing during the marathon were observed by a real-time kinematic (RTK) Global Positioning System (GPS), with a 2.2-centimeter vertical accuracy. Observed responses were discussed in both time domain and frequency domain by using a time series analysis. High (0.1–1 Hz) and low frequencies (0.00036–0.01172 Hz) of observed bridge responses under 12 different loads which occur in different quantities, different types and different time intervals were calculated in the frequency domain. It was seen that the calculated high frequencies are similar, except for the frequencies of rhythmic running, which causes a continuously increasing vibration. Any negative response was not determined, because this rhythmic effect continued only for a short time. Also when the traffic load was effective, explicit changes in the bridge movements were determined. Finally, it was seen that bridge frequencies which were calculated from the observations and the finite element model were harmonious. But the 9th natural frequency value of the bridge under all loads, except rhythmic running could not be determined with observations.

Compressive Strength Analysis of MWD Microchip Tracer

2014 ◽  
Vol 511-512 ◽  
pp. 561-564
Author(s):  
Ji Bo Li ◽  
Wei Ning Ni ◽  
San Guo Li ◽  
Zu Yang Zhu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Compressive Strength ◽  
Working Conditions ◽  
Failure Criterion ◽  
Strength Analysis ◽  
Design Phase ◽  
Key Issues ◽  
Simulation Results ◽  
Better Than

Pressure resistant performance of Measure While Drilling (MWD) microchip tracer to withstand the harsh downhole environment is one of the key issues of normal working. Therefore, it is an effective way to analyze pressure resistant performance of the tracer in the design phase. Compressive strength of the tracer was studied based on finite element method. Considering downhole complexity and working conditions during the processing of tracer roundness, material non-uniformity and other factors. In this study, researchers took sub-proportion failure criterion to determine the failure of tracer. Simulation results of two structures, with pin and without pin, show that both structures met the requirement of downhole compressive strength, and the structure with pin was better than the structure without pin. This study provides basis for downhole application of microchip tracers.

Strength Analysis of the Seat Anchorages for Large Passenger Vehicles Using Finite Element Method

2013 ◽  
Vol 658 ◽  
pp. 340-344
Author(s):  
Somsak Siwadamrongpong ◽  
Supakit Rooppakhun ◽  
Natchaya Murachai ◽  
Pakorn Burakorn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
Strength Analysis ◽  
Passenger Vehicle ◽  
Simulation Techniques ◽  
Vehicle Accident ◽  
Design For Safety ◽  
Vehicle Seat ◽  
Element Method

Since the vehicle accident is one of the major causes of dead and injury in Thailand, especially the large passenger vehicle. The seat anchorage was often damaged and lead to high number and critical of patient. To improve the safety of large passenger vehicle, seat anchorage should be investigated. The aim of this research was to analyze strength of seat anchorages for the bus according to European standard ECE Regulation 80 using finite element method and DOE(Design of Experimental) approach. In this study, the boundary conditions on finite element model of seat structure were defined according to the regulation. It is expected that the simulation techniques could be advantaged for seat anchorage analysis. This result will be used for further improvement of the bus seat anchorage design for safety and cost reduction in design processes.

The Design and Size Optimization of the New FCEV Subframe Based on Hypermesh Platform

2011 ◽  
Vol 328-330 ◽  
pp. 435-440
Author(s):  
Jun Liao ◽  
Lan Shan ◽  
Yan Feng
Keyword(s):  
Finite Element ◽  
Comparative Analysis ◽  
Finite Element Model ◽  
Mode Shape ◽  
High Strength Steel ◽  
High Strength ◽  
Element Model ◽  
Strength Analysis ◽  
Size Optimization ◽  
Optimal Size

The establishment of FCEV finite element model of the subframe is based on Hypermesh platform, and a new subframe structure is designed in accordance with the stiffness and strength analysis on the original subframe in all conditions. High-strength steel materials are used to optimize the design of this new structure, which result in the optimal size. Through the comparative analysis of the strength, stiffness, mode shape and quality on new subframe and the original one, it is verified that the design of the new subframe is reasonable and feasible.

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