The Effect of Roundness on the Buckling Strength for the Submerged Pressure Hull

2014 ◽  
Vol 644-650 ◽  
pp. 5133-5137
Author(s):  
Ching Yu Hsu ◽  
Cho Chung Liang ◽  
Tso Liang Teng ◽  
Chia Wei Chang
Keyword(s):  
Underwater Explosion ◽  
Cylinder Pressure ◽  
Pressure Loading ◽  
Finite Element Program ◽  
Buckling Strength ◽  
Element Program ◽  
Analysis Models ◽  
Explosion Load ◽  
Very High ◽  
Design Pressure

The pressure hull is the most important part of resisting pressure structures of the structural systems. The submerged pressure hull is subjected to very high hydrostatic pressure or underwater explosion load, which creates large compressive stress resultants. Due to this the pressure hull is susceptible to buckling. Buckling phenomena analysis is of greater importance in the design of the submerged pressure hulls. For the pressure hulls with local out-of-roundness, the operating depth will be greatly influenced and thus decreasing capability to resist pressure loading. Thus, this work employs the ABAQUS finite element program to analyze the effect of roundness on the buckling strength for the cylinder pressure hull. Sex kinds of out-of-roundness rateφ, 0%, 1%, 3%, 5%, 10% and 15%, were studied in this study. The bulking depth and collapse depth for the cylinder pressure hull with different out-of-roundness rate were calculated. The Analysis models and results of this study contribute to efforts to design pressure hull structures.

Simulation of Responses of Liquid Filled Double Bottom Structures Subjected to a Closely Underwater Explosion Shock Loading

2011 ◽  
Vol 88-89 ◽  
pp. 662-667 ◽  
Author(s):  
Ting Tang ◽  
Li Jun Wang ◽  
Jin Bo Ma
Keyword(s):  
Finite Element ◽  
Shock Loading ◽  
Underwater Explosion ◽  
Finite Element Program ◽  
Explicit Finite Element ◽  
Comparative Analyses ◽  
Element Program ◽  
The Difference ◽  
Bottom Structures

The purpose of this work is to study the effect of liquid in double bottom structures subjected to a closely underwater explosion shock loading. The comparative analyses are made by use of a commercial, explicit finite element program. Based on the difference of depth of liquid in double bottom structures and distance between explosive and outer bottom, six cases were simulated in this paper. The results show that liquid in cabins can enhance the resistance of double bottom structures to an underwater explosion.

METAKLETT – A Metal Cocklebur

2007 ◽  
Vol 344 ◽  
pp. 677-684 ◽  
Author(s):  
Hartmut Hoffmann ◽  
Christoph Hein ◽  
Seok Moo Hong ◽  
Hyun Woo So
Keyword(s):  
New Product ◽  
Manufacturing Companies ◽  
Finite Element Program ◽  
Joining Technology ◽  
Industrial Assembly ◽  
Element Program ◽  
The One ◽  
Thermal Influence ◽  
Very High ◽  
Good Agreement

The increasing individualization of products assigns manufacturing companies to new tasks like manufacturing various products in a more efficient way. This progression in the market leads on the one hand to a new product design and on the other hand to an improved production process. Both are necessary to reduce assembly, service and recycling costs. Hence the joining technology is and will become more and more important. The conventional joining technologies like welding, bonding, bolting or clamping have their own disadvantages especially in the field of flexibility. In order to reduce the effort for assembling and disassembling by retaining the requirements of the connection a new innovative joining technology is needed. In this study a new joining technology is introduced to become faster and more flexible in assembling and disassembling. The basic idea of this manufacturing technology comes from a “metal hook and loop fastener”. A hook and loop fastener consisting of metal has a lot of advantages for the fields of industrial assembly, service and recycling. Similar to the synthetic hook and loop fastener a metal one is characterized by easy closing and opening without special tools. And in comparison to the synthetic hook and loop fastener the transmissible forces are very high. An additional benefit can be gained for instance in shock absorbing or resistance against chemical and thermal influence. Two solutions are followed up to invent the “metal hook and loop fastener”. A one-to-one copy of the conventional hook and loop fastener is constructed in metal and specific solutions for the use of metal are tested. A conventional finite element program was used in order to optimize the construction of a metal cocklebur and the results show a good agreement with the experiment.

scholarly journals Non-Linear Analysis Of A Nuclear Containment Structure Under High Internal Pressure

2021 ◽  
Author(s):  
Ima Tavakkoli Avval
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Nuclear Power ◽  
Structural Failure ◽  
Finite Element Program ◽  
Nuclear Containment ◽  
Element Program ◽  
High Internal Pressure ◽  
Design Pressure ◽  
Concrete Ring

The main objective of the current study is to investigate the response of an internally pressurized nuclear power plant containment structure at pressure values higher than design pressure, and is focused on the response of prestressed concrete containment to ultimate global structural failure. The containment structure consists of a prestressed concrete cylindrical perimeter wall, with a prestressed concrete tori-spherical dome, prestressed concrete ring beam, and conventionally reinforced concrete base slab. The finite element program ANSYS is used to predict the non-liner behaviour of the containment structure. Different techniques available in ANSYS program to model steel reinforcements for reinforced concrete and prestressed concrete is estimated to define a more suitable approach to model prestressing system. The approach proposed here is capable of incorporating parameters such as variation in tendon layout and non-uniform prestress losses in comparison to those done by other researchers. It is concluded that the design criteria for the containment structure are fully satisfied. No through crack was observed at design pressure. The first through crack develops in the dome at a pressure of 2.1 times the design pressure. There is no damage to be expected to the reactor systems up to a pressure well above design pressure. It is observed that the containment structure subject of this study meets the design requirement of the current standards and behaves linearly in excess of 1.5 times the design pressure. The response of the internally pressurized containment structure including the major openings is investigated. It is concluded that presence of openings does not have a significant effect on the pressure capacity of the containment structure. The minor differences in the responses are at pressure values beyond the linear limit and are less than 5%. The response when openings are included are very similar to those without openings, except at the immediate neighboring of the equipment airlock opening. It is concluded that to predict the pressure response of containment structure, including the openings can be ignored. In case of need for a more exact response, only the equipment airlock can be included in the model

scholarly journals Buckling optimisation of sandwich cylindrical panels

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
M. Abouhamzeh ◽  
M. Sadighi
Keyword(s):  
Genetic Algorithm ◽  
Finite Element ◽  
Sheet Thickness ◽  
Optimal Solution ◽  
Finite Element Program ◽  
Buckling Strength ◽  
Cylindrical Panels ◽  
The Face ◽  
Global Buckling ◽  
Element Program

AbstractIn this paper, the buckling load optimisation is performed on sandwich cylindrical panels. A finite element program is developed in MATLAB to solve the governing differential equations of the global buckling of the structure. In order to find the optimal solution, the genetic algorithm Toolbox in MATLAB is implemented. Verifications are made for both the buckling finite element code and also the results from the genetic algorithm by comparisons to the results available in literature. Sandwich cylindrical panels are optimised for the buckling strength with isotropic or orthotropic cores with different boundary conditions. Results are presented in terms of stacking sequence of fibers in the face sheets and core to face sheet thickness ratio.

scholarly journals Non-Linear Analysis Of A Nuclear Containment Structure Under High Internal Pressure

2021 ◽  
Author(s):  
Ima Tavakkoli Avval
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Nuclear Power ◽  
Structural Failure ◽  
Finite Element Program ◽  
Nuclear Containment ◽  
Element Program ◽  
High Internal Pressure ◽  
Design Pressure ◽  
Concrete Ring

The main objective of the current study is to investigate the response of an internally pressurized nuclear power plant containment structure at pressure values higher than design pressure, and is focused on the response of prestressed concrete containment to ultimate global structural failure. The containment structure consists of a prestressed concrete cylindrical perimeter wall, with a prestressed concrete tori-spherical dome, prestressed concrete ring beam, and conventionally reinforced concrete base slab. The finite element program ANSYS is used to predict the non-liner behaviour of the containment structure. Different techniques available in ANSYS program to model steel reinforcements for reinforced concrete and prestressed concrete is estimated to define a more suitable approach to model prestressing system. The approach proposed here is capable of incorporating parameters such as variation in tendon layout and non-uniform prestress losses in comparison to those done by other researchers. It is concluded that the design criteria for the containment structure are fully satisfied. No through crack was observed at design pressure. The first through crack develops in the dome at a pressure of 2.1 times the design pressure. There is no damage to be expected to the reactor systems up to a pressure well above design pressure. It is observed that the containment structure subject of this study meets the design requirement of the current standards and behaves linearly in excess of 1.5 times the design pressure. The response of the internally pressurized containment structure including the major openings is investigated. It is concluded that presence of openings does not have a significant effect on the pressure capacity of the containment structure. The minor differences in the responses are at pressure values beyond the linear limit and are less than 5%. The response when openings are included are very similar to those without openings, except at the immediate neighboring of the equipment airlock opening. It is concluded that to predict the pressure response of containment structure, including the openings can be ignored. In case of need for a more exact response, only the equipment airlock can be included in the model

scholarly journals Dynamic Response and Parametric Studies of Elliptical Blast-Resistant Door with the Combined Structure for Large Vacuum Explosion Containers

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Saiwei Cheng ◽  
Xiaojie Li ◽  
Yang Wang ◽  
Yuxin Wang ◽  
Honghao Yan
Keyword(s):  
Dynamic Response ◽  
Blast Resistance ◽  
Diameter Ratio ◽  
Finite Element Program ◽  
Support Plate ◽  
Vacuum Degree ◽  
Calculation Results ◽  
Element Program ◽  
Combined Structure ◽  
Explosion Load

In recent years, with the improvement of environmental protection requirements year by year and the continuous expansion of explosive working scale, higher standards have been put forward for explosive working. It is hoped that the sphere of influence of the explosion can be limited to a minimal range. The explosion vessel is driven by such demand. As the explosion vessel’s key component, studying the blast-resistant door in depth is of great significance. This paper introduces a new elliptical blast-resistant door with the combined structure (EBD), mainly welded with an elliptical panel, arc support plate, and triangle support plate. The finite element program AUTODYN was used to calculate the explosion load, and LS-DYNA was used to calculate the blast-resistant door’s dynamic response. The calculation results show that the newly proposed EBD’s blast-resistance capacity is better than that of the traditional structure. To further study the factors that affect the dynamic response of the EBD, a parametric study was carried out on the EBD, mainly analyzing the influence of the vacuum degree in the explosion vessel, the number of explosives, and the diameter ratio of the EBD. The parametric calculation results show that reducing the vacuum degree in the explosion vessel and the number of explosives during explosion working can improve the blast-resistance capacity of the EBD. Based on the analysis of the dynamic response of four kinds of EBD with different diameter ratios under 0.2 atm explosion load, the optimal diameter ratio of the EBD is given.

Optimal Configuration for Stiffened Plates under the Effect of Underwater Explosion

2015 ◽  
Vol 813 ◽  
pp. 161-168
Author(s):  
Fathallah Elsayed ◽  
Hui Qi ◽  
Li Li Tong ◽  
Mahmoud Helal
Keyword(s):  
Underwater Explosion ◽  
Optimal Configuration ◽  
Steel Plates ◽  
Floating Structure ◽  
Shock Loads ◽  
Finite Element Program ◽  
Explicit Finite Element ◽  
Element Program ◽  
Complex Fluid ◽  
Stiffened Steel

The dynamic response of a floating structure subjected to underwater explosion is greatly complicated by the explosion of a high explosive, propagation of shock wave, complex fluid–structure interaction phenomena, and the dynamic behavior of the floating structures. A numerical investigation has been carried out to examine the behavior of stiffened steel plates subjected to shock loads resulting from an Underwater Explosion (UNDEX). The aim of this work is to obtain the optimal configuration to resist underwater shock loading. A non-linear dynamic numerical analysis of the underwater explosion phenomena associated with different geometrical stiffened steel plates is performed using the ABAQUS/Explicit finite element program. Special emphasis is focused on the evolution of mid-point displacements. Further investigations have been performed to study the effect of including material damping and the rate-dependant material properties at different shock loads. The results indicate that stiffener configurations and shock loads affect greatly the overall performance of steel plates and sensitive to the material data.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

Sign in / Sign up

Export Citation Format

Share Document