Papers by Keyword: Internal Pressure

Abstract: The aim of this study is to build a MATLAB code to predict the interlaminar radial strains, and stresses developed in a laminated composite tube. This code is only valid for symmetrical laminated composite tubes. The code can solve for tube that is subjected to uniform internal pressure. The written MATLAB code can save time and money compared to experiments and finite element simulations. Then, this code is validated with other published mentioned articles in this study. Good agreement is achieved which it means the built code can be used for the cases that agree with a symmetrical condition. The code is run to solve for radial, hoop, and shear strains. Also, it is used to solve for axial, radial, hoop, and shear stresses.

Abstract: Working temperature, internal pressure and the creep of bolted flange joints are the direct factors that influencing the gasket stress of bolted flange joints, the tightness of the whole system will be reduced because of these factors. thus the security level of bolted flange connection will be affected. In this paper, the deformation coordination equation of bolted flange connection system, the gasket compressive and resilient performance, as well as the gasket creep equation are combined to study the effect of internal pressure on bolted flange connections under a certain bolt preload and operating temperature, the equation about the relationship of the gasket force and internal pressure is simplified, and the main objective of the work is the calculation of the time-correlated gasket force, flange rotation and gasket unloading deformation under the different internal pressure. The results show that when the internal pressure is greater, the gasket force is smaller, on the contrary, the leakage rate are greater. Through the relevant conditions, in a period of the safe operation time, the maximum working internal pressure is got when reaching the condition of corresponding level of tightness.

Abstract: In this study, a series of multiaxial ratcheting tests under combined cyclic axial and inner pressure were conducted on M5 zirconium alloys tubes used as nuclear fuel cladding in Pressurized Water Reactors (PWRs) for the purpose to investigate the multiaxial ratcheting behavior of M5 and the factors of loading history may influence it. The experiment was stress-controlled and designed in a special loading path that all tubes in actually were under axial symmetrical cyclic load and constant inner pressure. A set of new patent multiaxial clamp was designed and applied to make sure the tubes can withstand inner pressure and axial load at the same time. A dynamic closed-loop multiaxial testing controller was used to manipulate two actuators simutaneously. Biaxial strain gauges were adopted to detect the signals of axial and hoop strain during the tests. The experimental results show that axial ratcheting strain decreases obviously within the original cycles reaching to a stop in certain cycles, the axial ratcheting increases with the cycles going. Loading history has obvious influence on the ratcheting behavior in axial direction. Higher stress amplitude level after loading history with lower stress amplitude level leads to an abnormal ratcheting behavior. The axial ratcheting shows a high sensitive to the complex loading history, especially when the stress amplitude is high. The hoop ratcheting strain accumulates continuously with the cycles going. Loading history has no obvious influence on hoop ratcheting strain and its ratcheting when the stress amplitude is low. The ratcheting strain and its rate shows more sensitive to the loading history when the stress amplitude increases to a certain value.

Abstract: The main objective of this experimental study was to investigate the effects of low velocity impact loading on the pressure bearing capacity of the E-glass/epoxy composite pipes. The pipes were produced by the conventional filament winding technique comprises of six axisymmetric layers with (±55°)₃ winding angles. The specimens were impacted at three different energy levels which are 5 J, 7.5 J, and 10 J using an instrumented drop weight impact testing machine (IMATEK IM10). The samples were then filled with water and subjected to burst test until distinct leakage failure is observed. The results indicate that the peak force and contact time increases with increased of impact energy. For impacted samples, the pressure tests show that the burst strength of the pipes decreases with increase in energy levels during impact loading. During the burst tests, several damage types named leakage and eruption were observed.

Abstract: The following work was focused on the analysis of adaptable pressurized sandwich components. The investigations were carried out to study the influence of internal pressure on mechanical characteristics. The bonding quality between core material and outer layers is of particular importance. For analyzing the bonding quality peel tests were conducted. In order to investigate the influence of the internal pressure and also of a bonding technique on bending properties four-point bending tests were carried out. In addition, the pressure characteristics were studied with compression tests during which a compression die was pressed into the component. After the compression tests, the rebound properties of pressurized and standard components were observed and compared.

Abstract: A systematic parametric study was carried out to investigate the elastic and elastic-plastic buckling behaviors of imperfect steel shell subject to axial compression and internal pressure. Studied parameters include the magnitude of internal pressure, steel strength, and ratio of cylinder radius to shell thickness. Design equations were proposed for calculating the elastic and elastic-plastic buckling strength of imperfect steel shells under combination of axial compression and internal pressure. The buckling strength predicated by proposed equations agrees well with that from the numerical simulation.

Abstract: Experimental, analytical and finite element techniques are commonly known methods used in determining highly localized stress occurring in the body under loading as a result of geometric discontinuities. In this study, we use NURBS-based isogeometric analysis (IGA) to investigate the stress concentration factor (SCF) on three-dimensional geometry with discontinuity feature. The results show that IGA technique is in good agreement with analytical values, thus providing a more effective realistic way of determining SCF.

Abstract: The tendency for coiled tubing grow in diameter and thin in wall under a combination loading of internal pressure and cyclic bending. The deformation mechanisms are described. The results show that the trends in coiled tubing deformation behavior are according with the context of theory: when the internal pressure exists, the tubing grew in the diameter; except for neutral point, the tubing thin in wall and the position in tensile is much thinner than in pressure; by the time of cycle increasing. The tubing grew in diameter and ovality, thin in wall.

Abstract: It has analyzed that there is no difference between positive and radial pressure of the interior of multi-directional squeeze casting solidified body. The isotropy of pressure makes the consistency of heat exchange coefficient of interface, crystalline growth velocity and plastic deformation, which thereby enables the solidification structure form of multi-directional squeeze casting parts to eliminate the defects of directional difference of single axis squeeze and non-uniformity of density. It has put forward that multi-directional squeeze casting technique shall be adopted for producing high-performance casting parts with uniform structure property and high density.

Abstract: A dent in a pipeline is a permanent plastic deformation of the circular cross section of the pipe. This paper discusses numerical results obtained from finite element (FE) simulation of pressurized pipe subjected to radial denting by a rigid indenter. Dent produced by rectangular shape indenter is assessed and the strain distribution of the pipe is investigated. The effect of internal pressure and dent depth on the distribution of strain is also studied. The results show that the circumferential and longitudinal strains increase with increasing the internal pressure and the depth of the dent. Numerical results are compared with an empirical theoretical model in order to demonstrate the accuracy of the analysis.