Papers by Keyword: External Pressure

Abstract: According to the requirement of vacuum leak detection container for small satellite, a set of vacuum leak detection container is developed. This paper discuss the design of model and the finite element analysis of different models. Through calculating the variation of the displacement X, Y, Z and the stress distribution of different parts and the rotation Z of the door flange and casing flange, determining whether the deflection of flange under internal vacuum will cause the sealing ring the fall of the sealing effect.

Abstract: The listing Corporation environmental information disclosure quality manifests the enterprise communicate with the outside world of social responsibility, from the perspective of the new institutional economics, the impetus of the environmental information disclosure quality is not only determined by the characteristics of the company, the more important pressure is from outside, this is also the original intention of the paper. This paper uses the Structural Equation Modeling with the LISREL, finding how the external pressure and the features of the company determining the level of information disclosure quality, hoping to find the way improving the listing Corporation environmental information disclosure.

Abstract: The elastic collapse of long cylinders under combined external pressure and axial force was investigated using analytical approach. Long cylindrical pipelines laid on the seabed are subjected to external pressure, initial defect will cause the local collapse of the pipelines. Due to the change of subsea environments and construction conditions, circular pipelines are subjected not only to the hydrostatic pressure, but also to forces of other forms, such as axial tension or compression, so on and so forth. This paper studies the local collapse and the morphological characteristics of a circular pipelines subjected to hydrostatic pressure and axial force. Governing equations based on Karman-Donnell`s shell theory are derived and are solved using Ritz method.

Abstract: Beside the residual stresses and axial loads, other factors of pipe like ovality, moment could also bring a significant influence on pipe deformation under external pressure. The Standard of API-5C3 has discussed the influences of deformation caused by yield strength of pipe, pipe diameter and pipe thickness, but the factor of ovality degree is not included. Experiments and numerical simulations show that with the increasing of pipe ovality degree, the anti-deformation capability under external pressure will become lower, and ovality affecting the stability of pipe shape under external pressure is significant. So it could be a path to find out the mechanics relationship between ovality and pipe deformation under external pressure by the methods of numerical simulations and theoretical analysis.

Abstract: Simulation analysis on prestressed concrete pipe was carried out by using finite element software ANSYS. The internal and external pressure which the pipeline is subject to is simulated in real work process, and deformation and stress distribution of building pipeline structure are got. We have great understanding in the mechanical properties, at the same time give a detailed introduction for the prefabrication and on-site construction process. Three aspects in this paper for analysis, design and construction can provide safe and reliable reference for design and construction of similar pipeline structure.

Abstract: Designers of modern conventional submarines are constantly striving to improve the platforms capabilities in a time of diverse missions. The inherent space and weight restrictions imposed on submarine design dictate a high level of optimisation and the implementation of advanced technologies to combat these often conflicting requirements. The design of external stowages is an area where this design paradigm is especially evident. In order to provide the RAN with additional mission flexibility and meet rigorous submarine requirements a novel approach was adopted to develop a composite pressure proof stowage. The design develops the use of composite laminate construction with the aim of minimising weight and cost, maintaining buoyancy and maintaining impact resistance using glass/carbon reinforced plastic for the prototype stowage. The resultant prototypes require structural validation including strain gauge verification to ensure that the final items can demonstrate adherence to stringent component and ultimately ship safety criteria.

Abstract: In this study, the elastic buckling behavior of general dome ends under presumed temperature distribution and external pressure was studied. The Finite Element Method (FEM) was used to predict the elastic buckling pressure behavior when the domes were subjected to various operating temperatures. The freedom of the edges of the dome ends was completely restricted to simulate clamped end conditions. The four-centered ellipse method was used to construct the geometry of the dome ends. The influence of geometrical parameters such as thickness, knuckle radius, and the ratio of minor axis to the major axis of dome ends and the effect of temperature on critical buckling pressure of hemispherical, ellipsoidal, and torispherical dome ends were studied. It has been found that the under thermal condition, the thickness and the shape of the domes have the most significant effect on the critical buckling pressure. Two models of torispherical and ellipsoidal dome ends are analyzed by using finite element analysis.

Abstract: In this paper, we used the Imperialist Competitive Algorithm (ICA) and Genetic Algorithm (GA) to find the minimum weight design of torispherical dome ends under external pressure load. According to fabrication and strength of material requirements, a group of compromised counters are selected and studied. Based on ASME Section VIII and BS5500 pressure vessel codes, a reasonable buckling pressure limit is proposed. Four-centered ellipse method is quite effective in designing and constructing the dome structure and it is used here to construct the torispherical dome ends. Two different size torispherical dome end models are selected and studied. Imperialist competitive algorithm is found to be very efficient and easy to use for the applications.

Abstract: The deep-sea pipe is an important part of mining lifting projects in the ocean floor. The uniqueness of environment conditions and design needs to determine the unforeseeable risks and challenges during the laying of pipeline. Based on extensive studies of loads acted on the pipeline and corresponding possible limit states for each installation method, a series of investigations on load-carrying capacity and buckling response of pipes under different loading combinations and various types defects (such as uniform ovalities)were carried out. In these calculations, the collapse pressure has been associated with the pressure maximum of a uniformly deforming long pipe. In experiments in a stiff pressure lifting pipelines, collapse is always localized as shown in Figures 3 and 4.However,because pipe’s localization takes place after the pressure maximum, the collapse pressure yielded by the 2-D analysis suffices for most cases. Exceptions are pipes with local imperfections, in the form of dents. The adequacy of this important conclusion will be demonstrated in the future application, where such predictions are compared to experiments.

Abstract: Many factors result in pipe collapses under certain external pressure. The relations among them have been studied by the pipe collapse tests. This pepper focused on the test analyses of steel pipe collapse resistance. Those include a pipe collapse pressure test under external pressure and illustrate both test and preparing theoretical analysis, and results of the collapse pressure with the effects on the tendency of ovality. In addition to various pipe collapse data and mechanical test methods, this study will offer a summary of the findings for the further intention of theories researches.